Optimization of Journal Bearings Considering Their Adjustable Design and Rotor Dynamics

The procedures of optimal design of journal bearings usually come down to finding the extremums of one or more key bearing characteristics. The load capacity, the minimum film thickness and the friction torque are most often considered as the optimization criteria. The parameters of dynamic rotor behavior require a significant amount of calculations to be estimated and are much rarely considered as such. Variable design of fluid film bearings brings additional challenges to their optimal design. In particular, they should provide the maximum efficiency of the control system impact on the rotor. This work presents an approach to the optimal designing of journal fluid film bearings, which takes into account the factors of the dynamic rotor behavior and the variability of the controlled parameters of adjustable bearings. The approach is implemented in solving the problem of parametric synthesis of an actively lubricated journal bearing. The abovementioned factors are taken into account in the objective functions. The optimization problem was solved using a genetic algorithm. The resulting set of Pareto optimal solutions can be used for choosing a balance between friction, stability and controllability of the bearing. However, the issue of developing the optimal control is offered to be considered as a separate stage in the active bearing synthesis procedure and is taken out of the scope of this study. Finally, the conclusions are drawn about the directions for further improvement of methods and tools for the optimal design of conventional and adjustable fluid film bearings.