The loss in charge process and effects on performance of wave rotor refrigerator

• In this work, LES was implemented to investigate the flow pattern of gradual channels open.
• The components of loss mechanics, such as mixing, viscosity and thermal dissipation, were analyzed.
• An improved wave rotor refrigerator cycle is established.
• The pressure loss can be reduced as much as 35% in this improved refrigeration system.

There are not only expansion waves, but also shock waves in wave rotor refrigerator (WRR) channels that usual considered to eliminate as far as possible in the past. Recognizing the shock wave has very high supercharging efficiency, an improved WRR cycle, which utilized the shock waves in rotor channels to recycle the expansion work during the process of refrigeration is established. Comparing with the proper port-timing and wave arrangement, the loss due to gradual opening can significant effect the performance of WRR. In this work, LES was implement to investigate the flow pattern of gradual channels open, and it is found that the distortion of contact interface have much relate with the streamwise vorticity that caused by the skin-friction of channel wall and baroclinic vorticity produced along the interface. The components of damping mechanics, such as mixing, viscosity and thermal dissipation, were analyzed and found that the performance of WRR can be improved with the increase of rotational speed in most cases. However, the viscosity and thermal dissipation could be worse at higher rotational speed that can reduce the efficiency of WRR. Experiment was designed and the performance of improved WRR was investigated by adjusting the major operational parameters, such as rotational speed and overpressure ratio. The experimental results show that the pressure loss can be greatly reduced and as much as 35% of pressure can be recycled in this improved refrigeration system.