A computational estimation of the critical rotational speed for finite hydrodynamically lubricated journal bearings

Abstract

Presents theoretical results regarding the computational estimation of the critical rotational speed in smooth or of negligible roughness and waviness hydrodynamically lubricated journal bearings. Results were provided using a developed calculational simulation code adapted to modelling of hydrodynamic lubrication regime encountered in the operation of various conventional or unconventional configuration finite journal bearings (j-b). It is concluded that empirical formulae of general character used to determine j-b rotational speed critical domain may either considerably underestimate or overestimate operational magnitudes, This fact leads to the necessity of use of high values for rotational speed safety factors in order to assure liquid lubrication and to avoid j-b contacts during operation. Relevant diagrams resulting from the present investigation show a direct estimation of critical j-b operational magnitudes.