Research on axis orbit of the journal bearing lubricated with oil and refrigerant mixtures in a twin-screw refrigeration compressor

In twin-screw refrigeration compressor for high pressure applications, journal bearing has been a preferred option to bear larger and larger radial force. Hence, the stability of rotor-journal bearing system is worth investigating to ensure the reliability of a twin-screw refrigeration compressor, which can be reflected on axis orbit. This paper presents a homogeneous two-phase flow model to calculate the axis orbit of journal bearing used in a twin-screw compressor, considering gas-induced force, unbalanced force and gravitational force. In order to compute gas-induced force acting on bearings by FEM, the p-V indicator diagram is measured experimentally. In addition, axial orbit under different evaporating temperature and different built-in volume ratio was investigated experimentally. Meanwhile it verifies that the proposed two-phase flow model has a good agreement in terms of orbit shape with the experimental result. Moreover, the effects of refrigerant mass fraction at supply groove and structural parameters are analyzed theoretically. (C) 2018 Elsevier Ltd and IIR. All rights reserved.