可大幅提高热声发动机压比的二级声压放大器

Two-stage cascade acoustic amplifier capable of remarkably increasing pressure ratio of thermoacoustic engine

为进一步提高声压放大器的输出压比(波动压力的最大值与最小值之比),同时降低功耗,在理论计算的基础上提出了一种级联式声压放大器结构,并进行了实验验证.以高纯N2作工质,在充气压力为2.140 MPa、行波热声发动机加热器壁面温度为670℃情况下,二级声压放大器把压比从放大器入口的1.177放大到1.619,这是目前在热声发动机上达到的最大压比.与单级声压放大器相比,其最大压力振幅提高了42.79%.放大器在1.23压比下输出160 W的最大声功.并采用DeltaE对二级声压放大器进行模拟,计算结果和实验结果吻合良好.

Based on numerical simulation, a novel cascade the acoustic amplifier was proposed to further increase the output pressure ratio and decrease the acoustic power consumption. Experiments were done to verify the performance of the cascade acoustic amplifier. The two-stage acoustic amplifier amplified the pressure ratio from 1. 177 to 1. 619 with nitrogen of 2. 140 MPa and heating temperature of 670 ℃, which is the highest pressure ratio obtained to date. The maximum output pressure amplitude increased by 42.79%o than that of the single-stage acoustic amplifier. The acoustic power was 160 W with pressure ratio of 1.23. Furthermore, DeltaE was used to simulate the performance of the two-stage cascade acoustic amplifier. Good agreements between results of computation and experiments were obtained.