Discussion: “A Finite Volume Analysis of the Thermohydrodynamic Performance of Finite Journal Bearings” (Han, T., and Paranjpe, R. S., 1990, ASME J. Tribol., 112, pp. 557–565)

The authors have made a valuable contribution in analyzing thermal effects in hydrodynamic bearing. The thermohydrodynamic theory uses finite volume method which can be applied successfully for different operating conditions with or without cavitation or reverse flow. The authors take into account the convention and dissipation terms in all directions. Their results show that thermal boundary conditions have a great influence on bearing performances. For steady-state operating conditions, the discussers have shown that [1] that thermoelastic displacements of both the shaft and the bush change significantly the bearing clearance which modify consequently the bearing performances. In most cases, it appears that the THD theory alone is not sufficient to predict bearing performances [1, 21]. For the second case treated in the paper, high temperatures and high pressures are calculated; these values should produce great deformations of the solids [22, 23]. Is the effect of deformations on performances of dynamically loaded bearings, like connecting-rod bearings, be more important than the effect of viscosity variations? The CPU time required for the resolution of the complete model seems slightly great. The adjunction of thermoelastic displacements would lead to increase drastically the calculation time. How would the authors simplify both thermal and deformation models in order to obtain reasonable computing time?