基于热声网络理论的驻波热声发动机起振模拟

Simulation of onset process of standing wave thermoacoustic engine based on thermoacoustic network theory

为了研究驻波热声发动机的起振条件并更好地理解热声振荡的机理,采用热声网络理论对驻波热声发动机的起振过程进行模拟.从线性热声理论中的控制微分方程出发,推导出存在温度梯度的板叠传输矩阵的3种不同表达式,并通过计算对比3种计算方法的精度.根据热声网络理论,对自行设计的驻波热声发动机进行整机模拟,计算起振温度和频率随充气压力和板叠间距的变化,并与实验结果进行对比,计算的起振温度随充气压力的变化趋势与实验结果基本相同.计算结果表明:不同的充气压力应选择不同的板叠间距.对该驻波热声发动机,其最佳的板叠间距应为热渗透深度的2.20～2.30倍.

This work studied study the onset conditions of a standing wave thermoacoustic engine and analyzed the mechanism of thermoacoustic oscillation.Using the control differential equations of linear thermoacoustic theory,three formulas for calculating the transfer array of the stack with temperature gradient were derived.Through the comparison,the accuracies of the three formulas were obtained.Based on the thermoacoustic network theory,a self-designed standing wave thermoacoustic engine was simulated.The onset temperatures and frequencies in different charging pressures and stack spaces were calculated and compared with the experimental results.The variation trend of the calculated onset temperature by charging pressure was almost the same as the experimental result.The calculation results also indicate that different stack spaces should be chosen for different charging pressures.For the standing wave thermoacoustic engine,the optimum stack space should be 2.20-2.30 times the thermal penetration depth.