Powder-lubricated, quasi-hydrodynamic journal bearings assist in controlling wear and hold promise for integration in outer space systems/mechanisms and in other hostile-environment applications where the use of conventional lubricants is impractical. Described herein are the thermal phenomena and an assessment of the thermal stability, heat generation and dissipation characteristics of slider-type, powder-lubricated bearings. Powder lubricant films provide lift and separate bearing surfaces and cause side leakage. The reduction in friction coefficient and, consequently, in the heat generated in the bearings, drastically reduces wear of the tribomaterials. Further, bearing side leakage carries away most of the heat generated by shear, reducing the heat to the critical bearing surfaces. Also presented are the thermohydrodynamic effects of powder lubrication (MoS2) on bearing performance criteria, e.g., temperature and friction coefficient as a function of speed and load, including the effect of powder flow rate on bearing performance and wear.

Issue Section:
Research Papers
Topics:
Journal bearings, Bearings, Heat, Wear, Friction, Leakage, Lubricants, Energy dissipation, Flow (Dynamics), Lubrication, Outer space, Shear (Mechanics), Stress, Temperature, Thermal stability, Thermohydrodynamics
1.
Heshmat, H., 1994, “On the Theory of Quasi-Hydrodynamic Mechanism of Powder Lubrication with Dry Powder: Application to Development of High-Speed Journal Bearings for Hostile Environments,” presented at the 20th Leeds-Lyon Symposium on Dissipative Processes in Tribology, Lyon, France, 7–10 Sept. 1993, Elsevier Science Publisher, Tribology Series 23.
2.
Heshmat, H., 1993, “Wear Reduction Systems for Coal-Fueled Diesel Engines—Part II The Experimental Results and Hydrodynamic Model of Powder Lubrication,” 9th International Conf. of Wear of Materials, Apr. 1993, San Francisco, CA; Wear Elsevier Sequoia, 162–164, pp. 508–517.
3.
Heshmat
H.
,
1992
a, “
The Quasi-Hydrodynamic Mechanism of Powder Lubrication—Part I: Lubricant Flow Visualization
,” STLE 46th Annual Meeting, April-May 1991, Paper No. 91-AM-4D-1,
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, Vol.
48
, No.
2
, pp.
96
–
104
.
4.
Heshmat
H.
,
1992
b, “
The Quasi-Hydrodynamic Mechanism of Powder Lubrication—Part II: Lubricant Film Pressure Profile
,” STLE/ASME Tribology Conf., St. Louis, Missouri, October 14–16, 1991,
Journal of STLE
, Vol.
48
, No.
5
, pp.
373
–
383
.
5.
Heshmat, H., and Brewe, D. E., 1992, “On Some Experimental Rheological Aspects of Triboparticulates,” Proceedings of the 18th Leeds-Lyon Symposium on Wear Particles: From the Cradle to the Grave, Lyon, 3–6 Sept. 1991, Elsevie Science Publishers, Tribology Series 18.
6.
Heshmat
H.
,
1991
, “
The Rheology and Hydrodynamics of Dry Powder Lubrication
,”
STLE Tribology Transactions
, Vol.
34
, No.
3
, pp.
433
–
439
.
7.
Heshmat
H.
,
Pinkus
O.
, and
Godet
M.
,
1989
, “
On a Common Tribological Mechanism Between Interacting Surfaces
,”
STLE Transactions
, Vol.
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, No.
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, pp.
32
–
41
.
8.
Heshmat
H.
, and
Shapiro
W.
,
1989
, “
High-Temperature, Unbalanced, Dry, Contact Face Seal Interfacial Phenomenon and Design Considerations
,”
Journal of STLE
, Vol.
45
, No.
4
, pp.
235
–
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.
9.
Heshmat, H., 1988, “Starved Bearing Technology: Theory and Experiment,” Ph.D. thesis, Mechanical Engineering Department, Rensselaer Polytechnic Institute, Troy, NY.
10.
Risdon, T. J., 1989, “Properties of Molybdenum Disulfide—MoS2 (Molybdenite),” Chemical Data Series Bulletin C-5C of Climax Molybdenum Co., a unit of AMAX Inc.
11.
Walton, J. P., and Gilbert, R., 1994, “Solid-Lubricated Roller Bearing Development—Ceramic Roller Bearing Design and Experimental Evaluation,” Technical Report WL-TR-94-2027, Wright Patterson Air Force Base, Ohio.
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