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Turbofan:Bearings - Revision history
2024-03-29T10:20:33Z
Revision history for this page on the wiki
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Vincent: /* Alternate bearings */ Blandon air bearings
2013-10-01T00:06:51Z
<p><span dir="auto"><span class="autocomment">Alternate bearings: </span> Blandon air bearings</span></p>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[https://en.wikipedia.org/wiki/Foil_bearing Foil bearings] are a particular type of fluid bearing, that "Unlike aero or hydrostatic bearings, foil bearings require no external pressurisation system for the working fluid, so the hydrodynamic bearing is self-starting". In [http://b-dig.iie.org.mx/BibDig/P06-0351/pdfs/track-16/GT2006-90791.pdf this other paper] <ref>Hooshang Heshmat, Michael J. Tomaszewski, James F. Walton II. '''Small gas turbine engine operating with high temperature foil bearing'''. In ''proceedings of GT2006 ASME Turbo Expo 2006: Power for land, sea and air'', may 2006.</ref>, a small centrifugal turbojet is built to evaluate the ability of [http://www.miti.cc/products-services.html MiTi]'s product, a foil bearing, to sustain very high rotation speeds (120'000rpm) and high temperature (800°C). The bearing has a low spacing between the rotor's journal and the stator fixation, but it is secured, in this paper, using a ball bearing on the compressor side, where the temperature is low. They planned to make a dual-foil bearing, we'll need to check on that. MiTi also demonstrated a [http://www.miti.cc/newsletters/20_150mm_foil_journal_bearing%20_hybrid_foil_magnetic_bearing.pdf hybrid foil magnetic bearing], that has the advantages of magnetic bearings at low speeds and those of foil bearings at high speeds.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[https://en.wikipedia.org/wiki/Foil_bearing Foil bearings] are a particular type of fluid bearing, that "Unlike aero or hydrostatic bearings, foil bearings require no external pressurisation system for the working fluid, so the hydrodynamic bearing is self-starting". In [http://b-dig.iie.org.mx/BibDig/P06-0351/pdfs/track-16/GT2006-90791.pdf this other paper] <ref>Hooshang Heshmat, Michael J. Tomaszewski, James F. Walton II. '''Small gas turbine engine operating with high temperature foil bearing'''. In ''proceedings of GT2006 ASME Turbo Expo 2006: Power for land, sea and air'', may 2006.</ref>, a small centrifugal turbojet is built to evaluate the ability of [http://www.miti.cc/products-services.html MiTi]'s product, a foil bearing, to sustain very high rotation speeds (120'000rpm) and high temperature (800°C). The bearing has a low spacing between the rotor's journal and the stator fixation, but it is secured, in this paper, using a ball bearing on the compressor side, where the temperature is low. They planned to make a dual-foil bearing, we'll need to check on that. MiTi also demonstrated a [http://www.miti.cc/newsletters/20_150mm_foil_journal_bearing%20_hybrid_foil_magnetic_bearing.pdf hybrid foil magnetic bearing], that has the advantages of magnetic bearings at low speeds and those of foil bearings at high speeds.</div></td></tr>
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<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">Air bearing are used by [http://www.bladonjets.com/products/micro-air-bearings/ Bladon Jets] for example, in their small turbines.</ins></div></td></tr>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Use of lubricating oil for cooling==</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Use of lubricating oil for cooling==</div></td></tr>
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Vincent
https://lcas.otaski.org/index.php?title=Turbofan:Bearings&diff=341&oldid=prev
Vincent: /* Oil displacement without external pumping */ discussion about the method
2012-10-23T01:42:59Z
<p><span dir="auto"><span class="autocomment">Oil displacement without external pumping: </span> discussion about the method</span></p>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Oil displacement without external pumping==</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Oil displacement without external pumping==</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>[https://en.wikipedia.org/wiki/Screw_conveyor Screw pumping] <del style="font-weight: bold; text-decoration: none;">may be used </del>as <del style="font-weight: bold; text-decoration: none;">a </del>way to <del style="font-weight: bold; text-decoration: none;">move </del>the oil <del style="font-weight: bold; text-decoration: none;">through </del>the engine<del style="font-weight: bold; text-decoration: none;">, i</del>.<del style="font-weight: bold; text-decoration: none;">e. parts that have to </del>be <del style="font-weight: bold; text-decoration: none;">lubricated </del>and <del style="font-weight: bold; text-decoration: none;">cooled</del>. The idea is to use the <del style="font-weight: bold; text-decoration: none;">work </del>of the <del style="font-weight: bold; text-decoration: none;">turbine </del>to <del style="font-weight: bold; text-decoration: none;">directly drive </del>the oil <del style="font-weight: bold; text-decoration: none;">pumping </del>without requiring external accessories. That does not solve the fact that cooling the oil <del style="font-weight: bold; text-decoration: none;">may require </del>external hardware, and that sealing is mandatory.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>[https://en.wikipedia.org/wiki/Screw_conveyor Screw pumping] <ins style="font-weight: bold; text-decoration: none;">is being assessed </ins>as <ins style="font-weight: bold; text-decoration: none;">the </ins>way to <ins style="font-weight: bold; text-decoration: none;">displace </ins>the oil <ins style="font-weight: bold; text-decoration: none;">throughout </ins>the engine. <ins style="font-weight: bold; text-decoration: none;">There will probably </ins>be <ins style="font-weight: bold; text-decoration: none;">two bearings in the engine, both requiring an oil bath </ins>and <ins style="font-weight: bold; text-decoration: none;">the shaft itself can probably also use a little refreshment</ins>. The idea is to use the <ins style="font-weight: bold; text-decoration: none;">rotation </ins>of the <ins style="font-weight: bold; text-decoration: none;">shaft </ins>to <ins style="font-weight: bold; text-decoration: none;">actually displace </ins>the oil without requiring external accessories. <ins style="font-weight: bold; text-decoration: none;">That would be a very lightweight solution and perhaps not that hard to implement, since our shaft is not hollow. The principle first has to be verified, then be tested with such high rotation rates in order to verify that the drag generated on the shaft is acceptable.</ins></div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> </div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>That does not solve the fact that cooling the oil <ins style="font-weight: bold; text-decoration: none;">requires </ins>external hardware <ins style="font-weight: bold; text-decoration: none;">(a heat exchanger)</ins>, and that sealing is mandatory <ins style="font-weight: bold; text-decoration: none;">in the oil inlet and outlet areas, generally where the bearings are</ins>.</div></td></tr>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Other hardware required for lubrication and bearing cooling==</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Other hardware required for lubrication and bearing cooling==</div></td></tr>
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Vincent
https://lcas.otaski.org/index.php?title=Turbofan:Bearings&diff=339&oldid=prev
Vincent: text fixes and https wikipedia links
2012-10-15T03:05:52Z
<p>text fixes and https wikipedia links</p>
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<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 03:05, 15 October 2012</td>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>=Bearings and cooling=</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>=Bearings and cooling=</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Rotational speed achieved by the engine will probably be <del style="font-weight: bold; text-decoration: none;">around </del>40000rpm. At <del style="font-weight: bold; text-decoration: none;">this speed</del>, regular ball bearings may overheat or suffer from a too fast wear. In real engines, bearings are constantly lubricated by <del style="font-weight: bold; text-decoration: none;">an </del>oil <del style="font-weight: bold; text-decoration: none;">bath</del>, which poses problems with regards to oil pressurization and leaks in other parts of the engine. Seals are consequently placed close to bearings to prevent leaks, generally carbon <del style="font-weight: bold; text-decoration: none;">leaks</del>. Accessories like oil pumps, pipes, fixations, filters and so on, are also required.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Rotational speed achieved by the engine will probably be <ins style="font-weight: bold; text-decoration: none;">above </ins>40000rpm. At <ins style="font-weight: bold; text-decoration: none;">these speeds</ins>, regular ball bearings may overheat or suffer from a too fast wear. In real <ins style="font-weight: bold; text-decoration: none;">turbine </ins>engines, bearings are constantly lubricated by oil <ins style="font-weight: bold; text-decoration: none;">jets</ins>, which poses problems with regards to oil pressurization and leaks in other parts of the engine. Seals are consequently placed close to bearings to prevent leaks, generally carbon <ins style="font-weight: bold; text-decoration: none;">seals. To enforce the seal, oil is contained in a casing with an internal pressure lower than the external pressure built from compressed air. That way, air can enter the oil casing, but oil cannot leak outside, in other parts of the engine</ins>.</div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> </div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Accessories like oil pumps, pipes, fixations, filters<ins style="font-weight: bold; text-decoration: none;">, tanks, heat exchangers </ins>and so on, are also required.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Bearings==</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Bearings==</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>===Ball bearings===</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>===Ball bearings===</div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Ball or roller bearings are the obvious way to guide rotating parts. They <del style="font-weight: bold; text-decoration: none;">provide good </del>mechanical constraints <del style="font-weight: bold; text-decoration: none;">on the axis orthogonal to the rotation</del>, they are inexpensive and their integration is reasonably simple.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Ball or roller bearings are the obvious way to guide rotating parts. They <ins style="font-weight: bold; text-decoration: none;">can handle high </ins>mechanical constraints <ins style="font-weight: bold; text-decoration: none;">radially or even axially</ins>, they are inexpensive and their integration is reasonably simple.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>[<del style="font-weight: bold; text-decoration: none;">http</del>://en.wikipedia.org/wiki/Silicon_nitride#Bearings Silicon nitride bearings] have lots of improvements over regular metal ball bearings. Balls are more than 60% less heavy, thus having a lower inertia at high speeds, implying a more softer contact with the tracks, allowing longer lifetime or higher reachable speeds. They also require less lubrication. Fortunately, silicon nitride bearings have reached <del style="font-weight: bold; text-decoration: none;">marked </del>with a large production, and are not over-expensive.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>[<ins style="font-weight: bold; text-decoration: none;">https</ins>://en.wikipedia.org/wiki/Silicon_nitride#Bearings Silicon nitride bearings] have lots of improvements over regular metal ball bearings. Balls are more than 60% less heavy, thus having a lower inertia at high speeds, implying a more softer contact with the tracks, allowing longer lifetime or higher reachable speeds. They also require less lubrication. Fortunately, silicon nitride bearings have reached <ins style="font-weight: bold; text-decoration: none;">market </ins>with a large production, and are not over-expensive.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>===Alternate bearings===</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>===Alternate bearings===</div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Fluid or magnetic bearings should be considered. They allow much higher rotation speeds and lower friction, but have two main drawbacks. At standby state, they release the <del style="font-weight: bold; text-decoration: none;">hard </del>constrain on moving parts <del style="font-weight: bold; text-decoration: none;">orthogonally to the rotating axis</del>. In reduced-size turbomachinery, where rotor and stator have to be adjusted to tens of microns, it<del style="font-weight: bold; text-decoration: none;">'s </del>quite complicated to use those bearings. The second drawback is that they require more external hardware, to pressurize the fluid or to provide magnetic energy.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Fluid or magnetic bearings should be considered. They allow much higher rotation speeds and lower friction, but have two main drawbacks. At standby state, they release the <ins style="font-weight: bold; text-decoration: none;">radial </ins>constrain on moving parts. In reduced-size turbomachinery, where rotor and stator have to be adjusted to tens of microns, it <ins style="font-weight: bold; text-decoration: none;">seems </ins>quite complicated to use those bearings. The second drawback is that they require more external hardware, to pressurize the fluid or to provide magnetic energy.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>However, magnetic bearings have been demonstrated in [http://books.google.com/books?id=AXtqMugS3TQC&lpg=PP1&pg=PA263#v=onepage&q&f=false this paper] <ref>S. Jana, V. Arun Kumar and M. Ananda. '''5-axes levitation of a rotor towards indigenization of the magnetic bearing technology'''. In ''Air breathing engines and aerospace propulsion: proceedings of NCABE 2004'', november 2004.</ref>, in which axial position accuracy is measured below 150µm for a 4kg rotor at around 2000rpm. The rotor position sensor has a resolution of 2µm per mV. <del style="font-weight: bold; text-decoration: none;">However</del>, no indication is given about the resting position of the rotor and how <del style="font-weight: bold; text-decoration: none;">that </del>impacts the clearance between rotor and stator.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>However, magnetic bearings have been demonstrated in [http://books.google.com/books?id=AXtqMugS3TQC&lpg=PP1&pg=PA263#v=onepage&q&f=false this paper] <ref>S. Jana, V. Arun Kumar and M. Ananda. '''5-axes levitation of a rotor towards indigenization of the magnetic bearing technology'''. In ''Air breathing engines and aerospace propulsion: proceedings of NCABE 2004'', november 2004.</ref>, in which axial position accuracy is measured below 150µm for a 4kg rotor at around 2000rpm. The rotor position sensor has a resolution of 2µm per mV. <ins style="font-weight: bold; text-decoration: none;">Unfortunately</ins>, no indication is given about the resting position of the rotor and how <ins style="font-weight: bold; text-decoration: none;">it </ins>impacts the clearance between rotor and stator.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>[<del style="font-weight: bold; text-decoration: none;">http</del>://en.wikipedia.org/wiki/Foil_bearing Foil bearings] are a particular type of fluid bearing, that "Unlike aero or hydrostatic bearings, foil bearings require no external pressurisation system for the working fluid, so the hydrodynamic bearing is self-starting". In [http://b-dig.iie.org.mx/BibDig/P06-0351/pdfs/track-16/GT2006-90791.pdf this other paper] <ref>Hooshang Heshmat, Michael J. Tomaszewski, James F. Walton II. '''Small gas turbine engine operating with high temperature foil bearing'''. In ''<del style="font-weight: bold; text-decoration: none;">proceedeings </del>of GT2006 ASME Turbo Expo 2006: Power for land, sea and air'', may 2006.</ref>, a small centrifugal turbojet is built to evaluate the ability of [http://www.miti.cc/products-services.html MiTi]'s product, a foil bearing, to sustain very high rotation speeds (120'000rpm) and high temperature (800°C). The bearing has a low spacing between the rotor's journal and the stator fixation, but it is secured, in this paper, using a ball bearing on the compressor side, where the temperature is low. They planned to make a dual-foil bearing, we'll need to check on that. MiTi also demonstrated a [http://www.miti.cc/newsletters/20_150mm_foil_journal_bearing%20_hybrid_foil_magnetic_bearing.pdf hybrid foil magnetic bearing], that has the advantages of magnetic bearings at low speeds and those of foil bearings at high speeds.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>[<ins style="font-weight: bold; text-decoration: none;">https</ins>://en.wikipedia.org/wiki/Foil_bearing Foil bearings] are a particular type of fluid bearing, that "Unlike aero or hydrostatic bearings, foil bearings require no external pressurisation system for the working fluid, so the hydrodynamic bearing is self-starting". In [http://b-dig.iie.org.mx/BibDig/P06-0351/pdfs/track-16/GT2006-90791.pdf this other paper] <ref>Hooshang Heshmat, Michael J. Tomaszewski, James F. Walton II. '''Small gas turbine engine operating with high temperature foil bearing'''. In ''<ins style="font-weight: bold; text-decoration: none;">proceedings </ins>of GT2006 ASME Turbo Expo 2006: Power for land, sea and air'', may 2006.</ref>, a small centrifugal turbojet is built to evaluate the ability of [http://www.miti.cc/products-services.html MiTi]'s product, a foil bearing, to sustain very high rotation speeds (120'000rpm) and high temperature (800°C). The bearing has a low spacing between the rotor's journal and the stator fixation, but it is secured, in this paper, using a ball bearing on the compressor side, where the temperature is low. They planned to make a dual-foil bearing, we'll need to check on that. MiTi also demonstrated a [http://www.miti.cc/newsletters/20_150mm_foil_journal_bearing%20_hybrid_foil_magnetic_bearing.pdf hybrid foil magnetic bearing], that has the advantages of magnetic bearings at low speeds and those of foil bearings at high speeds.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Use of lubricating oil for cooling==</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Use of lubricating oil for cooling==</div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">In real-world jet engines, cooling is the primary function of oil when conventional bearings are used, even more important than lubrication. That's well explained in [https://www.youtube.com/watch?v=WAia8PwMvQM this AgentJayz video]. A high flow rate of oil is then required, with a heat exchanger somewhere along the oil path. The other fluid for the heat exchanger can be air from the bypass duct or fuel, but in our highly size-constrained engine environment, we'll probably have to move some of the engine's equipment to the wings. But that will have to be studied after the bearing type has been chosen obviously.</ins></div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Oil displacement without external pumping==</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Oil displacement without external pumping==</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>[<del style="font-weight: bold; text-decoration: none;">http</del>://en.wikipedia.org/wiki/Screw_conveyor Screw pumping] <del style="font-weight: bold; text-decoration: none;">will </del>be used as a way to move the oil through the engine, i.e. parts that have to be lubricated and cooled. the work of the turbine <del style="font-weight: bold; text-decoration: none;">will thus </del>directly drive the oil pumping without requiring external accessories. <del style="font-weight: bold; text-decoration: none;">However, </del>cooling the oil may require external hardware, and sealing is <del style="font-weight: bold; text-decoration: none;">absolutely required</del>.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>[<ins style="font-weight: bold; text-decoration: none;">https</ins>://en.wikipedia.org/wiki/Screw_conveyor Screw pumping] <ins style="font-weight: bold; text-decoration: none;">may </ins>be used as a way to move the oil through the engine, i.e. parts that have to be lubricated and cooled. <ins style="font-weight: bold; text-decoration: none;">The idea is to use </ins>the work of the turbine <ins style="font-weight: bold; text-decoration: none;">to </ins>directly drive the oil pumping without requiring external accessories. <ins style="font-weight: bold; text-decoration: none;">That does not solve the fact that </ins>cooling the oil may require external hardware, and <ins style="font-weight: bold; text-decoration: none;">that </ins>sealing is <ins style="font-weight: bold; text-decoration: none;">mandatory</ins>.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>==<del style="font-weight: bold; text-decoration: none;">External </del>hardware required for lubrication==</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>==<ins style="font-weight: bold; text-decoration: none;">Other </ins>hardware required for lubrication <ins style="font-weight: bold; text-decoration: none;">and bearing cooling</ins>==</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del style="font-weight: bold; text-decoration: none;">A cooling device </del>will be required <del style="font-weight: bold; text-decoration: none;">if the oil gets </del>too <del style="font-weight: bold; text-decoration: none;">hot</del>, <del style="font-weight: bold; text-decoration: none;">which </del>is <del style="font-weight: bold; text-decoration: none;">likely. A basic </del>oil<del style="font-weight: bold; text-decoration: none;">-to-air heat exchanger should be sufficient</del>.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">Sensors </ins>will be required too, <ins style="font-weight: bold; text-decoration: none;">at least for oil temperature and displacement confirmation. Oil temperature informs about the status of the engine's bearings. Oil displacement sensor </ins>is <ins style="font-weight: bold; text-decoration: none;">required to ensure that there is no problem with the </ins>oil<ins style="font-weight: bold; text-decoration: none;">/cooling flow in the engine and that the measured temperature is not bogus</ins>.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del style="font-weight: bold; text-decoration: none;">Sensors will be required too, at least for </del>oil <del style="font-weight: bold; text-decoration: none;">temperature and displacement. Oil temperature may inform about the status of the engine, and with sufficient experiments and modeling can </del>be <del style="font-weight: bold; text-decoration: none;">used to infer turbine temperature. Oil displacement sensor is required to ensure that there is no problem with </del>the oil<del style="font-weight: bold; text-decoration: none;">/cooling flow in the engine and that </del>the <del style="font-weight: bold; text-decoration: none;">measured temperature is not bogus</del>.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">Simple </ins>oil <ins style="font-weight: bold; text-decoration: none;">filters should also </ins>be <ins style="font-weight: bold; text-decoration: none;">put somewhere on </ins>the oil <ins style="font-weight: bold; text-decoration: none;">lines to prevent </ins>the <ins style="font-weight: bold; text-decoration: none;">more obvious failures</ins>.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==References==</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==References==</div></td></tr>
</table>
Vincent
https://lcas.otaski.org/index.php?title=Turbofan:Bearings&diff=230&oldid=prev
Vincent: /* Alternate bearings */ miti's work
2011-10-23T00:37:42Z
<p><span dir="auto"><span class="autocomment">Alternate bearings: </span> miti's work</span></p>
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<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 00:37, 23 October 2011</td>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Fluid or magnetic bearings should be considered. They allow much higher rotation speeds and lower friction, but have two main drawbacks. At standby state, they release the hard constrain on moving parts orthogonally to the rotating axis. In reduced-size turbomachinery, where rotor and stator have to be adjusted to tens of microns, it's quite complicated to use those bearings. The second drawback is that they require more external hardware, to pressurize the fluid or to provide magnetic energy.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Fluid or magnetic bearings should be considered. They allow much higher rotation speeds and lower friction, but have two main drawbacks. At standby state, they release the hard constrain on moving parts orthogonally to the rotating axis. In reduced-size turbomachinery, where rotor and stator have to be adjusted to tens of microns, it's quite complicated to use those bearings. The second drawback is that they require more external hardware, to pressurize the fluid or to provide magnetic energy.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>However, magnetic bearings have been demonstrated in [http://books.google.com/books?id=AXtqMugS3TQC&lpg=PP1&pg=PA263#v=onepage&q&f=false this paper] <ref>S. Jana, V. Arun Kumar and M. Ananda. '''5-axes levitation of a rotor towards indigenization of the magnetic bearing technology'''. In ''Air breathing engines and aerospace propulsion: proceedings of NCABE 2004'', november 2004.</ref>.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>However, magnetic bearings have been demonstrated in [http://books.google.com/books?id=AXtqMugS3TQC&lpg=PP1&pg=PA263#v=onepage&q&f=false this paper] <ref>S. Jana, V. Arun Kumar and M. Ananda. '''5-axes levitation of a rotor towards indigenization of the magnetic bearing technology'''. In ''Air breathing engines and aerospace propulsion: proceedings of NCABE 2004'', november 2004.</ref><ins style="font-weight: bold; text-decoration: none;">, in which axial position accuracy is measured below 150µm for a 4kg rotor at around 2000rpm. The rotor position sensor has a resolution of 2µm per mV. However, no indication is given about the resting position of the rotor and how that impacts the clearance between rotor and stator.</ins></div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> </div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">[http://en.wikipedia.org/wiki/Foil_bearing Foil bearings] are a particular type of fluid bearing, that "Unlike aero or hydrostatic bearings, foil bearings require no external pressurisation system for the working fluid, so the hydrodynamic bearing is self-starting". In [http://b-dig.iie.org.mx/BibDig/P06-0351/pdfs/track-16/GT2006-90791.pdf this other paper] <ref>Hooshang Heshmat, Michael J. Tomaszewski, James F. Walton II. '''Small gas turbine engine operating with high temperature foil bearing'''. In ''proceedeings of GT2006 ASME Turbo Expo 2006: Power for land, sea and air'', may 2006.</ref>, a small centrifugal turbojet is built to evaluate the ability of [http://www.miti.cc/products-services.html MiTi]'s product, a foil bearing, to sustain very high rotation speeds (120'000rpm) and high temperature (800°C). The bearing has a low spacing between the rotor's journal and the stator fixation, but it is secured, in this paper, using a ball bearing on the compressor side, where the temperature is low. They planned to make a dual-foil bearing, we'll need to check on that. MiTi also demonstrated a [http://www.miti.cc/newsletters/20_150mm_foil_journal_bearing%20_hybrid_foil_magnetic_bearing.pdf hybrid foil magnetic bearing], that has the advantages of magnetic bearings at low speeds and those of foil bearings at high speeds</ins>.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Use of lubricating oil for cooling==</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Use of lubricating oil for cooling==</div></td></tr>
</table>
Vincent
https://lcas.otaski.org/index.php?title=Turbofan:Bearings&diff=228&oldid=prev
Vincent: Reference section
2011-10-19T22:40:26Z
<p>Reference section</p>
<table style="background-color: #fff; color: #202122;" data-mw="interface">
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<col class="diff-content" />
<tr class="diff-title" lang="en-GB">
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<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 22:40, 19 October 2011</td>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Sensors will be required too, at least for oil temperature and displacement. Oil temperature may inform about the status of the engine, and with sufficient experiments and modeling can be used to infer turbine temperature. Oil displacement sensor is required to ensure that there is no problem with the oil/cooling flow in the engine and that the measured temperature is not bogus.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Sensors will be required too, at least for oil temperature and displacement. Oil temperature may inform about the status of the engine, and with sufficient experiments and modeling can be used to infer turbine temperature. Oil displacement sensor is required to ensure that there is no problem with the oil/cooling flow in the engine and that the measured temperature is not bogus.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">==References==</ins></div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"><references /></ins></div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Category:Turbofan|Bearings and cooling]]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Category:Turbofan|Bearings and cooling]]</div></td></tr>
</table>
Vincent
https://lcas.otaski.org/index.php?title=Turbofan:Bearings&diff=227&oldid=prev
Vincent: /* Alternate bearings */ referencing instead of listing the ref.
2011-10-19T22:39:52Z
<p><span dir="auto"><span class="autocomment">Alternate bearings: </span> referencing instead of listing the ref.</span></p>
<table style="background-color: #fff; color: #202122;" data-mw="interface">
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<col class="diff-content" />
<col class="diff-marker" />
<col class="diff-content" />
<tr class="diff-title" lang="en-GB">
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td>
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 22:39, 19 October 2011</td>
</tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l13">Line 13:</td>
<td colspan="2" class="diff-lineno">Line 13:</td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Fluid or magnetic bearings should be considered. They allow much higher rotation speeds and lower friction, but have two main drawbacks. At standby state, they release the hard constrain on moving parts orthogonally to the rotating axis. In reduced-size turbomachinery, where rotor and stator have to be adjusted to tens of microns, it's quite complicated to use those bearings. The second drawback is that they require more external hardware, to pressurize the fluid or to provide magnetic energy.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Fluid or magnetic bearings should be considered. They allow much higher rotation speeds and lower friction, but have two main drawbacks. At standby state, they release the hard constrain on moving parts orthogonally to the rotating axis. In reduced-size turbomachinery, where rotor and stator have to be adjusted to tens of microns, it's quite complicated to use those bearings. The second drawback is that they require more external hardware, to pressurize the fluid or to provide magnetic energy.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>However, magnetic bearings have been demonstrated in [http://books.google.com/books?id=AXtqMugS3TQC&lpg=PP1&pg=PA263#v=onepage&q&f=false this paper]<del style="font-weight: bold; text-decoration: none;">: </del>S. Jana, V. Arun Kumar and M. Ananda. '''5-axes levitation of a rotor towards indigenization of the magnetic bearing technology'''. In ''Air breathing engines and aerospace propulsion: proceedings of NCABE 2004'', november 2004.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>However, magnetic bearings have been demonstrated in [http://books.google.com/books?id=AXtqMugS3TQC&lpg=PP1&pg=PA263#v=onepage&q&f=false this paper] <ins style="font-weight: bold; text-decoration: none;"><ref></ins>S. Jana, V. Arun Kumar and M. Ananda. '''5-axes levitation of a rotor towards indigenization of the magnetic bearing technology'''. In ''Air breathing engines and aerospace propulsion: proceedings of NCABE 2004'', november 2004<ins style="font-weight: bold; text-decoration: none;">.</ref></ins>.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Use of lubricating oil for cooling==</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Use of lubricating oil for cooling==</div></td></tr>
</table>
Vincent
https://lcas.otaski.org/index.php?title=Turbofan:Bearings&diff=226&oldid=prev
Vincent: lots of things. Introducing magnetic, fluid, and silicon nitride bearings.
2011-10-19T22:08:21Z
<p>lots of things. Introducing magnetic, fluid, and silicon nitride bearings.</p>
<table style="background-color: #fff; color: #202122;" data-mw="interface">
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<col class="diff-content" />
<col class="diff-marker" />
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<tr class="diff-title" lang="en-GB">
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<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 22:08, 19 October 2011</td>
</tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l1">Line 1:</td>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>=Bearings and cooling=</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>=Bearings and cooling=</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Rotational speed achieved by the engine will be around 40000rpm. At this speed, regular ball bearings may overheat or suffer from a too fast wear. In real engines, bearings are constantly lubricated by an oil bath, which poses problems with regards to oil leaks in other parts of the engine. Seals are <del style="font-weight: bold; text-decoration: none;">thus places </del>close to bearings to prevent leaks, generally carbon leaks. Accessories like oil pumps, pipes, fixations, filters and so on are also required.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Rotational speed achieved by the engine will <ins style="font-weight: bold; text-decoration: none;">probably </ins>be around 40000rpm. At this speed, regular ball bearings may overheat or suffer from a too fast wear. In real engines, bearings are constantly lubricated by an oil bath, which poses problems with regards to oil <ins style="font-weight: bold; text-decoration: none;">pressurization and </ins>leaks in other parts of the engine. Seals are <ins style="font-weight: bold; text-decoration: none;">consequently placed </ins>close to bearings to prevent leaks, generally carbon leaks. Accessories like oil pumps, pipes, fixations, filters and so on<ins style="font-weight: bold; text-decoration: none;">, </ins>are also required.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Bearings==</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Bearings==</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>==<del style="font-weight: bold; text-decoration: none;">Cooling </del>with lubricating oil==</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>==<ins style="font-weight: bold; text-decoration: none;">=Ball bearings===</ins></div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">Ball or roller bearings are the obvious way to guide rotating parts. They provide good mechanical constraints on the axis orthogonal to the rotation, they are inexpensive and their integration is reasonably simple.</ins></div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> </div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">[http://en.wikipedia.org/wiki/Silicon_nitride#Bearings Silicon nitride bearings] have lots of improvements over regular metal ball bearings. Balls are more than 60% less heavy, thus having a lower inertia at high speeds, implying a more softer contact </ins>with <ins style="font-weight: bold; text-decoration: none;">the tracks, allowing longer lifetime or higher reachable speeds. They also require less lubrication. Fortunately, silicon nitride bearings have reached marked with a large production, and are not over-expensive.</ins></div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> </div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">===Alternate bearings===</ins></div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">Fluid or magnetic bearings should be considered. They allow much higher rotation speeds and lower friction, but have two main drawbacks. At standby state, they release the hard constrain on moving parts orthogonally to the rotating axis. In reduced-size turbomachinery, where rotor and stator have to be adjusted to tens of microns, it's quite complicated to use those bearings. The second drawback is that they require more external hardware, to pressurize the fluid or to provide magnetic energy.</ins></div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> </div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">However, magnetic bearings have been demonstrated in [http://books.google.com/books?id=AXtqMugS3TQC&lpg=PP1&pg=PA263#v=onepage&q&f=false this paper]: S. Jana, V. Arun Kumar and M. Ananda. '''5-axes levitation of a rotor towards indigenization of the magnetic bearing technology'''. In ''Air breathing engines and aerospace propulsion: proceedings of NCABE 2004'', november 2004.</ins></div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> </div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">==Use of </ins>lubricating oil <ins style="font-weight: bold; text-decoration: none;">for cooling</ins>==</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Oil displacement without external pumping==</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Oil displacement without external pumping==</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[http://en.wikipedia.org/wiki/Screw_conveyor Screw pumping] will be used as a way to move the oil through the engine, i.e. parts that have to be lubricated and cooled. the work of the turbine will thus directly drive the oil pumping without requiring external accessories. However, cooling the oil may require external hardware, and sealing is absolutely required.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[http://en.wikipedia.org/wiki/Screw_conveyor Screw pumping] will be used as a way to move the oil through the engine, i.e. parts that have to be lubricated and cooled. the work of the turbine will thus directly drive the oil pumping without requiring external accessories. However, cooling the oil may require external hardware, and sealing is absolutely required.</div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">==External hardware required for lubrication==</ins></div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">A cooling device will be required if the oil gets too hot, which is likely. A basic oil-to-air heat exchanger should be sufficient.</ins></div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">Sensors will be required too, at least for oil temperature and displacement. Oil temperature may inform about the status of the engine, and with sufficient experiments and modeling can be used to infer turbine temperature. Oil displacement sensor is required to ensure that there is no problem with the oil/cooling flow in the engine and that the measured temperature is not bogus.</ins></div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Category:Turbofan|Bearings and cooling]]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Category:Turbofan|Bearings and cooling]]</div></td></tr>
</table>
Vincent
https://lcas.otaski.org/index.php?title=Turbofan:Bearings&diff=215&oldid=prev
Vincent: /* Oil displacement without pumping */
2011-07-28T01:11:27Z
<p><span dir="auto"><span class="autocomment">Oil displacement without pumping</span></span></p>
<table style="background-color: #fff; color: #202122;" data-mw="interface">
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<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 01:11, 28 July 2011</td>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Cooling with lubricating oil==</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Cooling with lubricating oil==</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>==Oil displacement without pumping==</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>==Oil displacement without <ins style="font-weight: bold; text-decoration: none;">external </ins>pumping==</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[http://en.wikipedia.org/wiki/Screw_conveyor Screw pumping] will be used as a way to move the oil through the engine, i.e. parts that have to be lubricated and cooled. the work of the turbine will thus directly drive the oil pumping without requiring external accessories. However, cooling the oil may require external hardware, and sealing is absolutely required.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[http://en.wikipedia.org/wiki/Screw_conveyor Screw pumping] will be used as a way to move the oil through the engine, i.e. parts that have to be lubricated and cooled. the work of the turbine will thus directly drive the oil pumping without requiring external accessories. However, cooling the oil may require external hardware, and sealing is absolutely required.</div></td></tr>
</table>
Vincent
https://lcas.otaski.org/index.php?title=Turbofan:Bearings&diff=214&oldid=prev
Vincent: page beginning
2011-07-28T00:29:35Z
<p>page beginning</p>
<table style="background-color: #fff; color: #202122;" data-mw="interface">
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<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td>
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 00:29, 28 July 2011</td>
</tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l1">Line 1:</td>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>=Bearings and cooling=</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>=Bearings and cooling=</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">Rotational speed achieved by the engine will be around 40000rpm. At this speed, regular ball bearings may overheat or suffer from a too fast wear. In real engines, bearings are constantly lubricated by an oil bath, which poses problems with regards to oil leaks in other parts of the engine. Seals are thus places close to bearings to prevent leaks, generally carbon leaks. Accessories like oil pumps, pipes, fixations, filters and so on are also required.</ins></div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">==Bearings==</ins></div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">==Cooling with lubricating oil==</ins></div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">==Oil displacement without pumping==</ins></div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">[http://en.wikipedia.org/wiki/Screw_conveyor Screw pumping] will be used as a way to move the oil through the engine, i.e. parts that have to be lubricated and cooled. the work of the turbine will thus directly drive the oil pumping without requiring external accessories. However, cooling the oil may require external hardware, and sealing is absolutely required.</ins></div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Category:Turbofan|Bearings and cooling]]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Category:Turbofan|Bearings and cooling]]</div></td></tr>
</table>
Vincent
https://lcas.otaski.org/index.php?title=Turbofan:Bearings&diff=213&oldid=prev
Vincent: /* Bearings and cooling */
2011-07-28T00:12:54Z
<p><span dir="auto"><span class="autocomment">Bearings and cooling</span></span></p>
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<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td>
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 00:12, 28 July 2011</td>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>[[Category:Turbofan|<del style="font-weight: bold; text-decoration: none;">Bearing]]</del></div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>[[Category:Turbofan|<ins style="font-weight: bold; text-decoration: none;">Bearings and cooling</ins>]]</div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del style="font-weight: bold; text-decoration: none;">[[Category:Turbofan|Cooling</del>]]</div></td><td colspan="2" class="diff-side-added"></td></tr>
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Vincent