Investigation and Optimization of a Twin-Screw Compressor with Internal Cooling Channels

Twin-screw compressors are used extensively in commercial and industrial applications. Profile optimization and capacity modulation solutions (e.g., slide valves, variable-speed, etc.) are continuously investigated to optimize the operation of the compressors and improve the performance. Previously, the authors have developed a detailed simulation model of a twin-screw air compressor with internal cooling channels to explore the feasibility of achieving quasi-isothermal compression process and prototype rotors were successfully 3D-printed. In this paper, further investigations are conducted at different operating conditions, including various pressure ratios, rotational speeds, and mass flow rates to improve the compressor efficiency. Since the compression process is coupled with heat transfer during the operation of the compressor, the interactions between solid (i.e., rotors) and fluid phases (i.e., air and coolant) are analyzed using a CFD model with conjugate heat transfer. The results of CFD model are used to quantify compression loads, assess the characteristics of the heat transfer processes, and optimize the internal flow through the cooling channels. The performance of the twin-screw compressor with internal cooling channels is compared with a conventional twin-screw compressor.