热声发动机的起振过程是一个产生并维持自激振荡的过程，研究热声自激振荡机理有助于进一步了解热声效应的实质。根据热声网络理论，建立了驻波热声发动机的整机网络。将热声网络比拟成电网络，利用厄米特式计算了输入热声网络的视在功流，功流平衡对应自激，在角频率虚部为零的情况下计算了热声发动机的阈值温度和运行频率。结果表明，计算值与实验值符合得较好，充气压力与阈值温度和运行频率的耦合关系大致相同。所得结论有助于进一步探究热声效应机理以及热声发动机系统的优化设计。%The onset process of a thermoacoustic prime mover is a process generating and maintaining self-excited oscillation. It is helpful to have a better understanding of thermoacoustic effect by investigating the mechanism of thermoacoustic self-excited oscillation. The network model of a representative standing-wave thermoacoustic prime mover is established on the basis of thermoacoustic network theory. Comparing thermoacoustic network to electric network, the apparent power flux which inputs the thermoacoustic network is calculated by using the Hermitian form. In the network, the apparent power flux balance means establishing the self-excited oscillation. Based on the above, the threshold temperature and operation frequency of a thermoacoustic prime mover are calculated on condition that the imaginary part of angular frequency is equal to zero. The calculation results are in good agreement with the experimental results. For the coupling relationship of the main pressure with the threshold temperature and operation frequency, the calculation results are roughly close to the experimental results. The obtained results are helpful for the further studying of the thermoacoustic effect and the optimal designing of a thermoacoustic system.
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