Pivoted-pad journal bearings lubrication design

Purpose - This paper aims to utilize an evolutionary algorithm as an optimization technique to solve design optimization of a pivoted-pad journal bearing performance characteristics considering objective functions which are contradictory to each other. These functions include fluid film thickness, film temperature, and power loss along with design variables vector, which consists of pad axial length to journal diameter ratio, pad arc length, bearing radial clearance, pad offset factor, and pad preload factor. Design/methodology/approach - In order to improve performance characteristics of the pivoted-pad journal bearing, the genetic algorithm (GA) was employed and the modeling of the bearing was represented with the finite element method. Also, a numerical method, global criterion, was conducted to validate the efficiency and applicability of the proposed method. Findings - This paper utilizes the GA to solve multi-objective optimization of the pivoted-pad journal bearing performance governed by design variables such as pad axial length to journal diameter ratio, pad arc length, bearing radial clearance, pad offset factor, and pad preload factor for a range of rotational speed. The global criterion method (GCM) proves that the proposed method is very efficient and useful for the optimal design of the pivoted-pad journal bearings. An acceptable results agreement between the GA and the GCM has been obtained. The GA is well suited to find the optimum solutions with a high probability since it starts with an initial set of solutions rather than a single solution. The GA explores different areas of search space in parallel and, it is good at exploitation. Originality/value - With the help of the proposed method, it will be possible to have an idea about bearing geometric parameters on a more rational basis, and to better predict the dynamic performance of rotor systems supported on the pivoted-pad journal bearings.