带声学放大器的行波热声发动机声阻抗特性

Acoustic impedance characteristics of traveling wave thermoacoustic engine with acoustic amplifier

通过分析带有声学放大器的行波热声发电系统中直线发电机的电-力-声类比图,发现直线发电机的最佳工作状态与行波热声发动机的输出声阻抗特性相关。采用DeltaEC软件计算带有声学放大器的行波热声发动机(以下简称系统)的输出声阻抗特性。计算结果发现,输出声阻抗虚部Xa为.1×107Pa·s·m^-3时,系统的最大输出声功率545.47W,最大热声转换效率为7.2%;当输出声阻抗虚部Xa在.3.9×106~.1×107Pa·s·m^-3之间变化,实部Ra在1.37×106~2.31×107Pa·s·m^-3之间时,等效位移在1.89~6mm之间变化,符合直线发电机的位移要求;结合输出声阻抗对压力与体积流率的相位差及系统工作频率的影响,发现声阻抗实部Ra应在1.37×106~2.31×107Pa·s·m^-3之间,声阻抗虚部Xa在.7.5×106~.1.0×107Pa·s·m^-3之间时,系统具有较好的工作状态。

In this paper it is found that the optimal working state of a linear alternator is related to the output acoustic impedance characteristics of the traveling wave thermoacoustic engine by analyzing the electric-force-acoustic analogy of the linear alternator in the traveling wave thermoacoustic power generation system with an acoustic amplifier (here- inafter referred to as system). The output acoustic impedance characteristics of the system are calculated by using DeltaEC software. The calculation results show that when the imaginary part of the acoustic impedance is Xa= 1×10 7 Pa s m^-3, the maximum output sound power of the system is 545.47 W, and the maximum thermoacoustic conversion efficiency is 7.2%. When the imaginary part X a of the output acoustic impedance varies from 3.9×10 6 to 1×107 Pa s m^-3 and when the real part R a varies between 1.37×106 and 2.31×107 Pa s m^-3, the equivalent displacement varies from 1.89 to 6 mm, which meet the displacement requirements of linear alternators. Combined with the influence of output acoustic impedance on the phase difference between pressure and volume flow rate and the operating frequency of the system, it is found that when the real part R a of acoustic impedance is in the range of 1.37×10 6 to 2.31×107 Pa s m^-3 and when the imaginary part X a of the acoustic impedance is between 7.5×106 and 1.0×107 Pa s m^-3, the system has a good working condition.