The design and influence of port arrangement on an improved wave rotor refrigerator performance

The port width and the offset between them are important structure parameters of a wave rotor refrigerator (WRR). The arrangement of ports decides the wave diagram in the wave rotor, which has a huge influence on the WRR performance. Designing a wave rotor mainly focuses on predicting the behavior of shock and expansion waves in wave rotor channels. This paper first presents an analytical design procedure for the pressure exchanger refrigerator, also known as WRR, to afford a theoretical port arrangement of the WRR rapidly. Then, the analytical design results are used as initial numerical model for CFD calculation. Based on the numerical simulation results, the port arrangements can be optimized. Charts and explanations are presented for the optimum design. Furthermore, a series of experiments were conducted to investigate the WRR performance under the optimized port sizes and offset. The results suggest that the COP of the system greatly changes with the geometrical arrangements. The highest COP of the system may be reduced by 41.8% with improper port widths or positions. The analysis of the WRR refrigeration system performance has revealed that expansion efficiency can be adversely affected by the compression efficiency, which means the improved WRR system have a great resistance to the working condition of volatility.