Numerical investigation of thermal deformation of meshing pairs in single screw compressor

Abstract

Single screw compressor serves as a core component in air compression system, mechanical vapor recompression system, low-temperature heat pump system and so on. However, under high temperature conditions, thermal deformation will lead to misaligned meshing between the vertical meshing pairs of the screw rotor and the star wheels. It would also lead to the serious abrasion of the components. Thus, it is necessary to investigate the thermal deformation mechanism of the single screw compressor to provide a guiding for clearance setting and strategy of assembling. In this paper, the thermal deformation mechanism of the meshing pairs in SSC is analyzed by using finite-element methods under the actual thermal boundary conditions tested by the infrared temperature camera. The results point out the deformation laws of the meshing pairs and torsional deformation of the screw rotor which cause the misaligned engagement. Influence of the thermal deformation on most of the clearances could be eliminated or controlled by setting reserved clearances. Such as the misaligned meshing could be controlled by reserving an axial assembling clearance and adjusting the bearing position. However, the torsional deformation of the screw rotor could only be modified by compensation machining. The method and results in this paper can be adopted for designing the meshing pairs and setting the design clearance of the compressor.