Static Characteristics and Dynamic Coefficients of a Gas–Oil-Lubricated Journal Bearing Under a Pressurized Refrigerant Environment

Abstract

The journal bearing is pivotal for the advancement of refrigerant compressors. While the gas–oil lubrication mechanism has been explored in some previous studies, the dynamic coefficients of gas–oil-lubricated bearings in pressurized refrigerant environments remain understudied. This article introduces a comprehensive analysis that extends the solubility-based compressible Reynolds equation (CRE) to derive the perturbed pressure in response to journal displacement and velocity. The approach generalizes the partial differential CRE (PDCRE) to calculate the dynamic coefficients, offering new insights into the dynamic coefficients of gas–oil-lubricated journal bearings under high-pressure conditions. The results delineate a notable elevation in the attitude angles under a pressurized refrigerant environment. It is also observed that the direct stiffness and coupled damping coefficients of two-phase bearings, especially under light-load scenarios, are significantly higher than the results from low-ambient pressure scenarios. Besides, higher rotational speeds increase the Sommerfeld number and attitude angle, yet concurrently reduce the stiffness and damping coefficients. The numerical results indicate that the characteristics of the investigated gas–oil-lubricated journal bearing are significantly different from those in atmospheric conditions, which should be meticulously considered in the bearing design and simulation of a high-pressure compressor.