Hybrid Air Foil Thrust Bearings Design and Performance Measurement

Abstract

Abstract Air foil bearings (AFBs) are widely used in high speed and low duty turbomachinery such as fuel cell air compressors, turbo blowers and micro gas turbines due to its high-speed operation, low power loss and good temperature adaptability. However, the applications of air foil thrust bearings to large power compressors such as closed-cycle supercritical CO2 turbines and high power single stage compressors still have many technical challenges due to load capacity limitation. Hybrid air foil bearing (HAFB) combines the benefits of AFB and hydrostatic air bearing. Compressed air is injected through a pipe behind the top foil to enhance pressure inside the thin film to increase bearing load capacity which can be controlled by changing source pressure. This paper presents the manufacturing process of hybrid air foil thrust bearings (HAFTBs) and measurements of bearing performance with three different orifice locations. The experiment was conducted to test the effect of orifice location and air supply pressure on bearing load capacity, friction torque and temperature. The experimental result shows that HAFTBs have significant bearing load capacity enhancement in comparison to AFBs. Source pressure and orifice location are the key parameters of the hybrid air foil thrust bearing.