Numerical analysis of screw compressor rotor and casing deformations

Performance and reliability of screw compressors is highly dependent on their operational clearances. Compressor structural parts including rotors and the casing are affected both by pressure and temperature of the working fluid to which they are exposed. The standard approach when simulating performance is to neglect these deformations and assume rigid compressor elements. In this paper a numerical solution which combines the solution of fluid field from Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) of solid elements is used to calculate deformations of the compressor elements. The temperature field obtained from CFD is extracted and applied to the surface of the solid parts where it was averaged in time and served as boundary conditions for solid body calculations. The FEM analysis performed in ANSYS showed encouraging results which can be used for analysis of changes in compressor clearances.