热声热机结构动力学分析

Analysis of structural dynamics in thermoacoustic engine

利用商业软件ANSYS建立热声热机模型,从结构动力学角度进行模拟研究,对其进行结构静力、模态和谐响应分析。在热声系统的关键位置布置监测点,得到热声系统内部位移、应力和应变等参数随压力和频率的变化关系。研究结果表明:随着充气压力的提升,应力应变基本呈现线性增大的趋势,且峰值点一一对应。随着结构模态的提高,热声热机的应力和应变因位置的不同而存在差异;热声系统的3阶和4阶模态下固有频率接近气体介质的振荡频率;由谐振管内表面布置的监测点所得结果可知,高密度的气体介质的振荡会在回热器中产生振动激励和声激励,并作用于谐振管,使声波和固体介质产生共振和耦合。

Mechanism of thermoacoustic engine was studied using ANSYS software. Simulation was made from the perspective of structural dynamics with the analysis of static force of structure and modal and harmonic response. Monitoring points were arranged at the crucial positon of the thermoacoustic engine to find the relationship of the variation of the displacement, stress and strain versus frequency or pressure. The results show that with the increase of pressure, the trends of stress and strain generally linearly increase, and the peaks are one-to-one corresponding. With the improvement of modal, thermoacoustic stress and deformation are dissimilar in different locations; the natural frequency of thermoacoustic system is close to the oscillation frequency of the gas medium at modal 3 and 4; the result of monitoring point on the inner surface of the resonator shows that high-density gas medium would produce vibration excitation and sound excitation, which makes the acoustic and structural modes couple with each other.