大尺度热声发动机的关键问题研究

Aiming at the zero boil-off demand of liquid hydrogen storage tank, the paper discusses the feasibility of a thermoacoustic engine driving a 300 W @ 20 K cryocooler and the key problems that need to be solved. First, SAGE is used to perform one-dimensional numerical calculations and optimization design of the thermoacoustically driven pulse tube cryocooler to obtain the structural parameters and thermal performance of the system. Then CFD method is used to carry out a two-dimensional simulation of the complex flow and heat transfer problems in the large-scale thermoacoustic engine, aiming to clarify the key problems in the actual system and propose corresponding solutions. The results show that the thermal buffer tube plays the most critical role in the mixing loss of cold and heat. The removal of the secondary cooler has a significant effect on suppressing the local secondary flow and reducing the mixing loss of cold and hot in the thermal buffer tube, and the distribution of its internal velocity field also has a regulating effect on the Gedeon flow. In addition, the problems of heat exchanger for waste heat utilization and thermal stress of shell in large-scale thermoacoustic engine are discussed.