Mathematical Modeling of the Working Cycle of Oil Injected Rotary Twin Screw Compressor

Abstract

Oil injected twin-screw air compressors are widely used for medium pressure applications in cryogenic industries. Conversion of air compressors for helium applications is in great demand due to their inherent advantages. Mathematical analysis of oil injected twin-screw compressor is carried out on the basis of the laws of perfect gas, and standard thermodynamic relations. Heat transfer coefficient required for computer simulation is experimentally obtained and used in performance prediction, where the working medium being air or helium. A computer model is developed for calculating compressor performance and to validate the results with experimental data. The flow coefficients required for simulation to calculate leakage flow rates are obtained from efficiency versus clearance curves. Effect of design parameters of compressor on power and volumetric efficiencies are analyzed and presented.