大尺度热声发动机的关键问题研究

Research on Key Problems of a Large-scale Thermoacoustic Engine

本文针对液氢储罐零蒸发需求,探讨热声发动机驱动300 W@20 K低温制冷机的可行性及所需解决的关键问题。首先利用SAGE对热声驱动脉管制冷机系统进行整机一维模拟计算和优化设计,获得系统结构参数与热力性能,再采用CFD方法针对大尺度热声发动机的复杂流动和换热问题进行二维仿真,旨在阐明实际系统中存在的关键问题并提出相应解决措施。结果表明,热缓冲管在冷热混合损失中起到最为关键的作用,去除次水冷器对于抑制热缓冲管中的局部二次流从而降低冷热混热损失效果明显,同时其内部速度场的分布还对Gedeon直流具有一定的调节作用。此外,本文还讨论了大尺度热声发动机中的余热利用换热器与承压壳热应力等问题。

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.