Test Rig Development for Static Load Performance Measurements of a Hydrostatic Thrust Bearing

Abstract

In the field of turbomachinery, such as compressors and pumps, the pressure gradient between the inlet and discharge pressures causes axial loads on a rotor-bearing system [1]. Hydrostatic thrust bearings are crucial components in turbomachinery as they offer high axial stiffness, damping coefficients, and load capacity [2]. Therefore, testing hydrostatic thrust bearings for their static and dynamic load characteristics requires a reliable test rig. Vertical test rigs are simple to design as they avoid gravitational loads, but are challenging to assemble and align [3]. This work describes the development of a vertically fixed thrust bearing test rig for measuring the static load characteristics of hydrostatic thrust bearings [4-6]. Lee and Ryu [4] developed the test rig to evaluate the static load characteristics of an air foil thrust bearing. Based on the configuration in Ref. [4], Lim et al. [5] built a test rig to investigate the static load characteristics of a hydrostatic thrust bearing. Furthermore, Choi et al. [6] presented an additively manufactured hybrid thrust bearing and measured its static load characteristics, which had the same dimensions as Ref. [5]. To study the static and dynamic load characteristics of hybrid thrust bearings in various test fluids (such as air, water, and LN2), the current work revamped the test rig by changing the bearing housing. In the vertically mounted test rig, the thrust collar is fixed onto the base plate to prevent deformation of the collar and avoid tilting of the collar with respect to the bearing surface. Displacement sensors that measure the target disk displacement indirectly measure the test bearing's displacement. The measurement results from the developed test rig demonstrate reliable and repeatable test data, which are validated with the test data from Ref. [5].