Design, fabrication, experimentation and analysis of high-speed microscale gas bearings
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2001.
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| Format: | Thesis |
| Language: | eng |
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Massachusetts Institute of Technology
2005
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| Online Access: | http://hdl.handle.net/1721.1/8876 |
| _version_ | 1826195318660661248 |
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| author | Wong, Chee Wei, 1975- |
| author2 | Stuart A. Jacobson and Alan H. Epstein. |
| author_facet | Stuart A. Jacobson and Alan H. Epstein. Wong, Chee Wei, 1975- |
| author_sort | Wong, Chee Wei, 1975- |
| collection | MIT |
| description | Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2001. |
| first_indexed | 2024-09-23T10:10:49Z |
| format | Thesis |
| id | mit-1721.1/8876 |
| institution | Massachusetts Institute of Technology |
| language | eng |
| last_indexed | 2024-09-23T10:10:49Z |
| publishDate | 2005 |
| publisher | Massachusetts Institute of Technology |
| record_format | dspace |
| spelling | mit-1721.1/88762019-04-12T17:11:33Z Design, fabrication, experimentation and analysis of high-speed microscale gas bearings Wong, Chee Wei, 1975- Stuart A. Jacobson and Alan H. Epstein. Massachusetts Institute of Technology. Dept. of Mechanical Engineering. Massachusetts Institute of Technology. Dept. of Mechanical Engineering. Mechanical Engineering. Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2001. Includes bibliographical references (p. [183]-190). Microengine Program. The all-silicon device consist of a free-rotating microturbine, with 4.2 mm rotor diameter, enclosed within a five wafer fusion-bonded stack. Of note are the low aspect ratio journal bearing and large journal bearing clearances, primarily limited by microfabrication, from which stable bearing operation must first be demonstrated as viable. Theoretical modeling of the gas-lubricated hydrostatic journal bearing presents design charts, a comparative study of existing predictions and investigation into rotational effects to consider the bearing stiffness during operation. Continued experimental refinements and exploration with our microfabricated rotor achieved rotational speeds up to 1.4 million rpm and peripheral speeds in excess of 300 m/s. Extensive experimental data is presented with analysis, focusing on whirl motion and its harmonic resonances as candidates for instability. Causes of ultimate failure is suggested with recommendations for further improvements. Moreover, in an effort to accomplish self-sustained microbearings, the axial thrust bearing is redesigned for a self-acting spiral groove bearing. The chosen constraint is to incorporate the hydrodynamic thrust bearing with minimal changes to the current device, whilst providing the required load and stiffness. Stability analysis and rarefaction considerations on the optimized design suggests an operating range for the bearing, leading to a hybrid design for ample stiffness during initial operation. The design is then developed into a microfabrication process flow and implemented successfully into the MicroBearing test devices. Experiments on a hybrid bearing were performed to gage the spiral grooves characteristics. A purely hydrodynamic aft thrust bearing device is then tested for operation through low speeds, although the effects of the spiral grooves could not be accurately determined. Finally, transition to a hydrodynamic operating mode for a hybrid bearing is demonstrated. by Chee Wei Wong. S.M. 2005-08-23T16:01:31Z 2005-08-23T16:01:31Z 2001 2001 Thesis http://hdl.handle.net/1721.1/8876 48815694 eng M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 190 p. 16163682 bytes 16163437 bytes application/pdf application/pdf application/pdf Massachusetts Institute of Technology |
| spellingShingle | Mechanical Engineering. Wong, Chee Wei, 1975- Design, fabrication, experimentation and analysis of high-speed microscale gas bearings |
| title | Design, fabrication, experimentation and analysis of high-speed microscale gas bearings |
| title_full | Design, fabrication, experimentation and analysis of high-speed microscale gas bearings |
| title_fullStr | Design, fabrication, experimentation and analysis of high-speed microscale gas bearings |
| title_full_unstemmed | Design, fabrication, experimentation and analysis of high-speed microscale gas bearings |
| title_short | Design, fabrication, experimentation and analysis of high-speed microscale gas bearings |
| title_sort | design fabrication experimentation and analysis of high speed microscale gas bearings |
| topic | Mechanical Engineering. |
| url | http://hdl.handle.net/1721.1/8876 |
| work_keys_str_mv | AT wongcheewei1975 designfabricationexperimentationandanalysisofhighspeedmicroscalegasbearings |