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The Effect Of Journal Roughness And Foil Coatings On The Performance Of Heavily Loaded Foil Air Bearings
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Book Synopsis The Effect of Journal Roughness and Foil Coatings on the Performance of Heavily Loaded Foil Air Bearings by :
Download or read book The Effect of Journal Roughness and Foil Coatings on the Performance of Heavily Loaded Foil Air Bearings written by and published by . This book was released on 2001 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: Foil air bearing load capacity tests were conducted to investigate if a solid lubricant coating applied to the surface of the bearing's top foil can function as a break-in coating. Two foil coating materials, a conventional soft polymer film (polyimide) and a hard ceramic (alumina), were independently evaluated against as-ground and worn (run-in) journals coated with NASA PS304, a high-temperature solid lubricant composite coating. The foil coatings were evaluated at journal rotational speeds of 30000 rpm and at 25 deg C. Tests were also performed on a foil bearing with a bare (uncoated) nickel-based superalloy top foil to establish a baseline for comparison. The test results indicate that the presence of a top foil solid lubricant coating is effective at increasing the load capacity performance of the foil bearing. Compared to the uncoated baseline, the addition of the soft polymer coating on the top foil increased the bearing load coefficient by 120 percent when operating against an as-ground journal surface and 85 percent against a run-in journal surface. The alumina coating increased the load coefficient by 40 percent against the as-ground journal but did not have any affect when the bearing was operated with the run-in journal. The results suggest that the addition of solid lubricant films provide added lubrication when the air film is marginal indicating that as the load capacity is approached foil air bearings transition from hydrodynamic to mixed and boundary lubrication.
Book Synopsis The effect of journal roughness and foil coatings... by :
Download or read book The effect of journal roughness and foil coatings... written by and published by DIANE Publishing. This book was released on with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Effect of Journal Roughness and Foil Coatings on the Performance of Heavily Loaded Foil Air Bearings ... Nasa by : United States. National Aeronautics and Space Administration
Download or read book The Effect of Journal Roughness and Foil Coatings on the Performance of Heavily Loaded Foil Air Bearings ... Nasa written by United States. National Aeronautics and Space Administration and published by . This book was released on 2003* with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Performance and Durability of High Temperature Foil Air Bearings for Oil-Free Turbomachinery by : C. DellaCorte
Download or read book Performance and Durability of High Temperature Foil Air Bearings for Oil-Free Turbomachinery written by C. DellaCorte and published by . This book was released on 2000 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: The performance and durability of advanced, high temperature foil air bearings are evaluated under a wide range (10-50 kPa) of loads at temperatures from 25 to 650 deg C. The bearings are made from uncoated nickel based superalloy foils. The foil surface experiences sliding contact with the shaft during initial start/stop operation. To reduce friction and wear, the solid lubricant coating, PS 304, is applied to the shaft by plasma spraying. PS304 is a NiCr based Cr2O3 coating with silver and barium fluoride/calcium fluoride solid lubricant additions. The results show that the bearings provide lives well in excess of 30,000 cycles under all of the conditions tested. Several bearings exhibited lives in excess of 100,000 cycles. Wear is a linear function of the bearing load. The excellent performance measured in this study suggests that these bearings and the PS 304 coating are well suited for advanced high temperature, oil-free turbomachinery applications.
Book Synopsis 15th Wear of Materials by : Peter J. Blau
Download or read book 15th Wear of Materials written by Peter J. Blau and published by Elsevier. This book was released on 2005-10-03 with total page 826 pages. Available in PDF, EPUB and Kindle. Book excerpt: These proceedings of the 15th International Conference on Wear of Materials focus on the friction and wear of materials in various applications under different environments from the nanometer scale to the meter scale. The conference provides a unique international forum for researchers and practitioners from different disciplines to exchange latest results. Coverage includes: . Wear assessment and monitoring . Wear modeling, mechanisms, mapping and prediction . Wear-corrosion testing and control . Surface engineering for wear and wear-corrosion control . Development of new wear test methods and wear test methodologies . Wear of materials for biomedical applications . Wear of non-equilibrium materials: from atomic dimensions to the micro-scale . Wear of hard and superhard materials . Wear of materials in the earthmoving, minerals processing and mining industries
Book Synopsis A Systems Approach to the Solid Lubrication of Foil Air Bearings for Oil-Free Turbomachinery by :
Download or read book A Systems Approach to the Solid Lubrication of Foil Air Bearings for Oil-Free Turbomachinery written by and published by . This book was released on 2002 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Journal of Tribology written by and published by . This book was released on 2004 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Monthly Catalog of United States Government Publications by :
Download or read book Monthly Catalog of United States Government Publications written by and published by . This book was released on 2003 with total page 720 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781721641321 Total Pages :32 pages Book Rating :4.6/5 (413 download)
Book Synopsis Friction and Wear Characteristics of Cu-4Al Foil Bearing Coating at 25 and 650 Degree C by : National Aeronautics and Space Administration (NASA)
Download or read book Friction and Wear Characteristics of Cu-4Al Foil Bearing Coating at 25 and 650 Degree C written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-21 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: The friction and wear performance of a Cu-4Al top foil coating has been investigated in Generation I foil air bearings. The copper alloy was applied by a novel deposition technique (ion diffusion) and the journal was coated with PS304, a plasma spray deposited high temperature composite solid lubricant coating. The ion diffusion coating process deposits a desirable smooth layer compared to other methods like cathodic arc deposition. The tribological performance of bearings with and without Cu-4Al foil coatings were evaluated through start-stop tests on an air bearing test rig at 25 and 650 C. The results indicate that the Cu-4Al assists during the initial break-in period, gives more stable friction performance with respect to temperature, and appears to prevent top foil wear at high temperature. The measured load capacity coefficient was 0.5, which was comparable to earlier testing of more advanced design Generation III bearings coated with standard cathodic arc deposited Cu-4Al. However, further studies are needed to determine if deeper penetration of the copper alloy into the foil would help make the transition in friction behavior from contact with the Cu-4Al coated foil to contact with the base foil material more gradual. Also, future work is recommended to assess the performance of ion diffusion coatings with different Cu-based alloy compositions and to investigate the effect the coating has on the elastic modulus of the foil material. Stanford, Malcolm K. and DellaCorte, Christopher Glenn Research Center NASA/TM-2004-212972, NAS 1.15:212972, E-14445
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781721530519 Total Pages :34 pages Book Rating :4.5/5 (35 download)
Book Synopsis A Systems Approach to the Solid Lubrication of Foil Air Bearings for Oil-Free Turbomachinery by : National Aeronautics and Space Administration (NASA)
Download or read book A Systems Approach to the Solid Lubrication of Foil Air Bearings for Oil-Free Turbomachinery written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-20 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Foil air bearings are self-acting hydrodynamic bearings which rely upon solid lubricants to reduce friction and minimize wear during sliding which occurs at start-up and shut-down when surface speeds are too low to allow the formation of a hydrodynamic air film. This solid lubrication is typically accomplished by coating the non-moving foil surface with a thin, soft polymeric film. The following paper introduces a systems approach in which the solid lubrication is provided by a combination of self lubricating shaft coatings coupled with various wear resistant and lubricating foil coatings. The use of multiple materials, each providing different functions is modeled after oil-lubricated hydrodynamic sleeve bearing technology which utilizes various coatings and surface treatments in conjunction with oil lubricants to achieve optimum performance. In this study, room temperature load capacity tests are performed on journal foil air bearings operating at 14,000 rpm. Different shaft and foil coating technologies such as plasma sprayed composites, ceramic, polymer and inorganic lubricant coatings are evaluated as foil bearing lubricants. The results indicate that bearing performance is improved through the individual use of the lubricants and treatments tested. Further, combining several solid lubricants together yielded synergistically better results than any material alone. DellaCorte, Christopher and Zaldana, Antonio R. and Radil, Kevin C. Glenn Research Center NASA/TM-2002-211482, NAS 1.15:211482, E-13250, ARL-TR-2867
Book Synopsis The Role of Radial Clearance on the Performance of Foil Air Bearings by :
Download or read book The Role of Radial Clearance on the Performance of Foil Air Bearings written by and published by . This book was released on 2002 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Load capacity tests were conducted to determine how radial clearance variations affect the load capacity coefficient of foil air bearings. Two Generation HI foil air bearings with the same design but possessing different initial radial clearances were tested at room temperature against an as-ground PS 304 coated journal operating at 30000 rpm. Increases in radial clearance were accomplished by reducing the journal's outside diameter via an in-place grinding system. From each load capacity test the bearing load capacity coefficient was calculated from the rule-of-thumb (ROT) model developed for foil air bearings. The test results indicate that, in terms of the load capacity coefficient, radial clearance has a direct impact on the performance of the foil air bearing. Each test bearing exhibited an optimum radial clearance that resulted in a maximum load capacity coefficient. Relative to this optimum value are two separate operating regimes that are governed by different modes of failure. Bearings operating with radial clearances less than the optimum exhibit load capacity coefficients that are a strong function of radial clearance and are prone to a thermal runaway failure mechanism and bearing seizure. Conversely, a bearing operating with a radial clearance twice the optimum suffered only a 20% decline in its maximum load capacity coefficient and did not experience any thermal management problems. However, it is unknown to what degree these changes in radial clearance had on other performance parameters, such as the stiffness and damping properties of the bearings.
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781721194568 Total Pages :34 pages Book Rating :4.1/5 (945 download)
Book Synopsis Performance and Durability of High Temperature Foil Air Bearing for Oil-Free Turbomachinery by : National Aeronautics and Space Administration (NASA)
Download or read book Performance and Durability of High Temperature Foil Air Bearing for Oil-Free Turbomachinery written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-16 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: The performance and durability of advanced, high temperature foil air bearings are evaluated under a wide range (10-50 kPa) of loads at temperatures from 25 to 650 C. The bearings are made from uncoated nickel based superalloy foils. The foil surface experiences sliding contact with the shaft during initial start/stop operation. To reduce friction and wear, the solid lubricant coating, PS304, is applied to the shaft by plasma spraying. PS304, is a NiCr based Cr2O3 coating with silver and barium fluoride/calcium fluoride solid lubricant additions. The results show that the bearings provide lives well in excess of 30,000 cycles under all of the conditions tested. Several bearings exhibited lives in excess of 100,000 cycles. Wear is a linear function of the bearing load. The excellent performance measured in this study suggests that these bearings and the PS304 coating are well suited for advanced high temperature, oil-free turbomachinery applications. DellaCorte, C. and Valco, M. J. and Radil, K. C. and Heshmat, H. Glenn Research Center NASA/TM-1999-209187, NAS 1.15:209187, E-11697
Book Synopsis Evaluation of Advanced Solid Lubricant Coatings for Foil Air Bearings Operating at 25 and 500 C by : Christopher DellaCorte
Download or read book Evaluation of Advanced Solid Lubricant Coatings for Foil Air Bearings Operating at 25 and 500 C written by Christopher DellaCorte and published by . This book was released on 1998 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis A New Foil Air Bearing Test Rig for Use to 700 C and 70,000 Rpm by : Christopher DellaCorte
Download or read book A New Foil Air Bearing Test Rig for Use to 700 C and 70,000 Rpm written by Christopher DellaCorte and published by . This book was released on 1997 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Proceedings of the World Tribology Congress III--2005 by :
Download or read book Proceedings of the World Tribology Congress III--2005 written by and published by . This book was released on 2005 with total page 1040 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Load Capacity Estimation of Foil Air Journal Bearings for Oil-Free Turbomachinery Applications by :
Download or read book Load Capacity Estimation of Foil Air Journal Bearings for Oil-Free Turbomachinery Applications written by and published by . This book was released on 2000 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Influence of Shaft Deflection and Surface Roughness on Load-carrying Capacity of Plain Journal Bearings by : Francis Harvey Raven
Download or read book Influence of Shaft Deflection and Surface Roughness on Load-carrying Capacity of Plain Journal Bearings written by Francis Harvey Raven and published by . This book was released on 1959 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt:
