Optimization of oil flow rate and oil film temperature rise in high speed hydrodynamic journal bearings

In this paper, the optimum design procedure of high-speed, short journal bearings under laminar and turbulent flow conditions is developed based on three kinds of methods such as Successive Quadratic Programming, Genetic Algorithm and Direct Search. Applying the short bearing assumption to the modified turbulent Reynolds equation, simplified closed form design formulae are obtained for the eccentricity ratio, friction force, film temperature rise, supply lubricant quantity and whirl onset velocity as a function of design variables such as radial clearance, slenderness ratio and averaged viscosity of lubricants. Then, using these formulae, the design variables, which optimize the objective function given by a linear summation of temperature rise and supply lubricant quantity with respective weighting factor, are determined for a wide range of journal rotational speeds under various constraints.