三级行波热声发动机的声场特性

The acoustic field of a three-stage traveling-wave thermoacoustic engine

设计并搭建了一台三级行波热声发动机,并基于线性热声理论和实验研究分析了该热声发动机的声场特性。结果表明:理论计算中各级加热功率相同时,发动机声场对称;而实验中加热功率相同时声场存在不一致性,需要输入特定的加热功率来控制三级加热温度基本相同,从而保证三级声场基本对称,此时相邻两级对应位置的压力相位差在120°±10°范围内;随着充气压力和加热温度的升高,系统工作频率略有升高,变化不显著,系统压力振幅和压比则增大明显。以氮气和氦气为工质时,工作频率分别在20 Hz和55 Hz左右;实验中压比分别达到了1.28和1.18。

A three-stage Traveling-Wave ThermoAcoustic Engine(TWTAE) was designed and built,and the acoustic field was analyzed based on the linear thermoacoustic theory and the experiment.In the theoretical calculation,the acoustic field of the three-stage TWTAE is symmetrically distributed when the heating power of different stages is equal.In the experiment,the inconsistency of the acoustic field among three stages exists when the heating power is equal so that the acoustic field is not completely symmetrical.But the heating temperatures of three stages can be the same by controlling the heating power to ensure the acoustic field is basically symmetrical.And the pressure phase difference between the corresponding positions of two adjacent stages is in the range of 120±10°.With the increase of the mean pressure and heating temperature,the working frequency increases slightly and the change is not obvious,while the pressure amplitude and pressure ratio increase obviously.When nitrogen and helium are used as the working gas,the frequencies are about 20 Hz and 55 Hz,and the pressure ratios can reach 1.28 and 1.18,respectively.