Analysis of Thermal Deformation of a Rough Slider and Its Asperities and Its Impact on Load Generation in Parallel Sliders

Authors: Prawal Sinha, Getachew Adamu

Abstract:

Heating is inevitable in any bearing operation. This leads to not only the thinning of the lubricant but also could lead to a thermal deformation of the bearing. The present work is an attempt to analyze the influence of thermal deformation on the thermohydrodynamic lubrication of infinitely long tilted pad slider rough bearings. As a consequence of heating the slider is deformed and is assumed to take a parabolic shape. Also the asperities expand leading to smaller effective film thickness. Two different types of surface roughness are considered: longitudinal roughness and transverse roughness. Christensen-s stochastic approach is used to derive the Reynolds-type equations. Density and viscosity are considered to be temperature dependent. The modified Reynolds equation, momentum equation, continuity equation and energy equation are decoupled and solved using finite difference method to yield various bearing characteristics. From the numerical simulations it is observed that the performance of the bearing is significantly affected by the thermal distortion of the slider and asperities and even the parallel sliders seem to carry some load.

Keywords: Thermal Deformation, Tilted pad slider bearing, longitudinal roughness, transverse roughness, load capacity

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1331837

References:

[1] A. Fogg, "Fluid Film Lubrication of Parallel Thrust Surfaces." In: Proc. Inst. Mech. Eng., vol.155, pp. 49-53, 1946.
[2] F. Osterle, A.Charnes and A.Saibel, "On the Solution of the Reynolds Equation for Slider Bearing Lubrication-IV- The Parallel Surface Slider Bearing without Side Leakage," Trans. ASME, pp. 1133-1136, 1953.
[3] W. Lewicki, "Theory of Hydrodynamic Lubrication in Parallel Sliding," Engnr., London 200, pp. 939-941, 1955.
[4] A. Cameron, "The viscosity Wedge," Trans. ASME vol. 1, pp. 248-253, 1958.
[5] J. Young, "The Thermal Wedge in Hydrodynamic Lubrication," Eng. J. vol. 45, pp. 46-54, 1962.
[6] A.O. Lebeck, "Parallel Load Support in the Mixed Friction Regime, Part I-The Experimental Data," Trans. ASME, J. Trib. Vol. 109, pp.189-195, 1987.
[7] O.C. Zienkiewicz, "Temperature distribution within lubricating films between parallel bearing surfaces and its effect on the pressures developed." In: Proc. of conference on lubrication and wear, paper No. 7, Inst. Mech. eng., London, 1957.
[8] C.M. Rodkiewicz, Prawal Sinha, "On the Lubrication Theory: A Mechanism Responsible for Generation of the Parallel Bearing Load Capacity," Trans. ASME, J. Lub. Tech. vol.115, pp. 584-590, 1993.
[9] H. Ezzat, S. Rhode, "A Study of Hydrodynamic Performance of Finite Slider Bearings," Trans. ASME, J. Lub. Tech. vol.95, 3, pp. 298-307, 1973.
[10] O. Pinkus, "Thermal Aspects of Fluid Film Tribology," ASME Press, New York, 1990.
[11] B.V.Rathish, P.S.Rao, and P.Sinha, "Stream Line Upwind Petrov- Gaerkin Finite Element Analysis of Thermal Effects on Load Carrying Capacity in Slider Bearings," Num. Heat Transfer. Part A: Applications vol.38, pp.305-328, 2000.
[12] M.M. Khonsari, "A Review of Thermal Effects in Hydrodynamic Bearings. Part I: Slider/Thrust Bearings, Part II:" Journal Bearings, ASLE Trans. Vol. 30, pp. 19-33, 1987.
[13] S.T.Tzeng, H.Saibel, "Surface Roughness Effect on Slider Bearing Lubrication," ASME Trans. Vol. 10, pp. 334-338, 1967.
[14] H. Christensen, K. Tonder, "Tribology of Roughness: Stochastic Models of Hydrodynamic Lubrication," SINTEF report 10/69-18, 1969.
[15] H. Christensen, "Stochastic Models of Hydrodynamic Lubrication of Rough Surfaces." In: Proc. Inst. mech. Eng. Vol. 184, pp.1013-1022, 1969-70.
[16] H. Christensen, J.B. Shukla, and S. Kumar, "Generalized Reynolds Equation for Stochastic Lubrication and its Application," J, Mech. Eng. Sci. vol. 17, pp. 262-270, 1975.
[17] J. Ramesh, C. Majumdar, and N.S. Rao, "Thermohydrodynamic Analysis of Submerged Oil Journal Bearings Considering Surface Roughness Effects," Trans. ASME, J. Trib. Vol. 119, pp. 100-106, 1997.
[18] L. Chang, C. Farnum, "A Thermal Model for Elastohydrodynamic Lubrication of Rough Surfaces," Tribology Trans. Vol. 35, pp. 281-286, 1992.
[19] B.P. Huynh, S. Loe, "Influence of Location, Number and Shape of Corrugations in Slider Bearings," Anziam J. vol. 45, pp. C1017-C1038, 2004.
[20] A.A. Ozap, H. Umur, "Optimum Surface Profile Design and performance Evaluation of Inclined Slider Bearings," Current Science, vol. 90, pp. 1480-1491, 2006.
[21] Sinha Prawal, A. Getachew, "THD analysis for slider bearing with roughness: special reference to load generation in parallel sliders," Acta Mechanica, vol. 207, Issue 1, pp 11, 2009.