Surrogate Model Development for Air Foil Thrust Bearings With Chevron-Patterned Trailing Edge1

Abstract

Air foil thrust bearings provide some advantages over oil-lubricated thrust bearings. The use of these bearings reduces weight and increases dynamic stability, making it possible to reach high rotational speeds. However, as the bearing reaches high rotational speeds, the higher amount of heat generated results in reduced efficiency, deterioration, and even failure of the rotating machinery system. To overcome this, better thermal management is needed for air foil thrust bearings. Addressing this challenge, this study proposes the use of a chevron pattern at the trailing edge of the top foil to enhance air stream mixing, thus influencing heat dissipation. The main purpose of this study is to identify the optimal design parameters of the top foil trailing edge shape and provide a guideline for future air foil thrust bearing design. In this regard, 3D computational fluid dynamics (CFD) simulations are conducted to evaluate an air thrust foil bearing model performance. The highest temperature value occurring in the fluid and load-carrying capacity is selected as the output to find optimum design values. The design of experiments (DOE) technique is utilized for generating the sample points. A surrogate model is then used jointly with a multi-objective optimization to minimize the peak temperature in the air film and increase the load-carrying capacity. The optimal configuration is compared with the baseline, which is also used to validate the computational model with experimental data. This optimal design approach using a surrogate model can be used for further studies on improving the efficiency of air foil thrust bearings.