Structural Optimization Study Of Wave Rotor Of External-Circulation Dissipative Gas Wave Refrigerator

The External-Circulation Dissipative Gas Wave Refrigerator which used wave rotor as core refrigeration part is a new gas wave refrigeration equipment. Compared with the traditional gas wave refrigerator, rotating wave refrigerator and static gas wave machine, it has many advantages such as compacted construction, strong resistance to fluctuation and can working without liquid accumulation. Its application prospect is wide. This article mainly focuses on optimization of structural of wave rotor. The complex flow behavior in rotating channels is analyzed by unsteady flow of gas dynamics theory. The performance of refrigeration equipment which is influenced by the change of the structure size of channels is studied deeply by the method of numerical simulation and experimental study. The main research conclusions are described as follow.(1)The working process in channel of wave rotor of the refrigeration equipment is analyzed. It is divided into four stages, including high-pressure compressing stage, high-temperature exhausting stage, low-pressure recycling gas stage and low temperature exhausting stage. The motion behavior of wave system in the channels of each stage is studied. The principles and discipline of thermal separation of two opening shock tube is revealed. The ideal working wave diagram of refrigerator is ascertained. The matching of structure parameters of refrigeration equipment is proposed based on this theory.(2) The inner whole process is separated into expansion process of driving gas and internal cycle gas compression process, then the complete thermodynamic analytical model of refrigerator is established. Simulation studied the main factors, which affect the refrigerator performance such as refrigerator expansion ratio, compression ratio and air flow ration, and predict the performance of refrigeration at different parameters matching. The results showed that, the supercharge characteristic of external-circulation dissipative gas wave refrigerator is limited. The non-isentropic characteristic of wave process increase while improving the operation expansion ratio. Though this method can increase the thermal separation temperature, but can not increase the isentropic efficiency of refrigeration.(3)It's the first time using three-dimensional single channel model to simulate the complex flow behavior within wave rotor channel. The reason of the contact surface distortion and mixing at the incident phase is analyzed. It's found that when the height of incident nozzle and the rotor channel is fixed, and the high-pressure nozzle width or the ratio of channel width and height is increased, the incidence efficiency loss can be significantly reduced.(4) In order to simplify the machine model, the structure of external-circulation dissipative is omitted. The influences of operating parameters of pressurized side of refrigeration process on cooling performance have been researched. It is found that when the structure and operation parameters of expansion side are fixed, the compression ratio and the operating pressure of pressurized side have a significant effect on cooling performance.(5) Experimental results of new refrigerator whose wave rotor is smaller and channel width is reduced revealed that the cooling efficiency decreased about 8%. It is proved that narrow width of the rotor channels will seriously affect cooling performance.The results and conclusions of this study will be instructive to the gas wave refrigeration technology and follow-up study and structure improvement of external-circulation dissipative gas wave refrigerator.