热声斯特林发动机热动力学特性的CFD研究 第二部分:热声转换特性及热声声流的研究

Study on thermodynamic and dynamic performance of thermoacoustic Stirling heat engines by using CFDPart Two: Investigation on conversion characteristics from heat energy to acoustic power and Gedeon acoustic stream

研究了热声斯特林发动机的声场特性和热力特性,计算了波动压力和体积流率振幅及两者的相位差、截面平均温度以及声功流在系统内的沿程分布,与实验及预期的趋势相符合。对热声斯特林发动机内部的Gedeon声直流进行了研究。通过监测系统内截面的质量流率周期分布特性观测到Gedeon直流的存在,计算了直流量的大小及在系统内的分布特性,并采用风扇模型抑制了直流,给出了直流抑制过程中的系统性能变化。进一步验证了CFD研究的有效性。

The first part of this study presented the evolution process of self-excited thermoacoustic oscillation, which preliminarily verified the feasibility and validity of the CFD method. This paper deals with the second part： the characteristics of energy conversion from heat to acoustic power and Gedeon acoustic streaming within the thermoacoustic Stirling heat engine. The distributions of dynamic pressure and volume velocity amplitude, their phase difference, cross-sectional cycle-averaged temperature and acoustic power flow in the system are shown, demonstrating a good agreement with experimental and expected results. By monitoring the cycled-averaged mass flow rate of cross section, the Gedeon flow was detected and calculated. The fan model of Fluent was used to suppress the Gedeon flow, and the results were given for imposing different second-order pressure drop by using the fan model.