非对称双级环路行波热声热机的实验研究*

对于双级环路行波热声热机,两个热声核的相对位置直接影响到其起振温度,而热声热机的起振温差决定了其可利用的热源品位。基于线性热声理论分析,通过改变两个热声核的相对位置,研究了两个热声核的相对位置改变对其起振温差、压力振幅和压比等的影响。结果表明,双级环路行波热声热机的起振温度随着两个热声核从中心对称位置逐步靠近时先下降再上升,当两个热声核之间的谐振管长度比例为1:3.5时,系统获得最小的起振温差为59.6℃（工质为N₂,充气压力为2.5 MPa）。在相同温差下,该系统在谐振管长度比例为1:3.5的位置相较于其他位置具有较大的压力振幅和压比。

Experimental Research on Asymmetric Two-Stage Loop Traveling Wave Thermoacoustic Engine

For a two-stage loop traveling-wave thermoacoustic engine, the relative position of two thermoacoustic cores directly affects its starting temperature. While the starting temperature difference of the thermoacoustic engine determines its available heat source grade. Based on the analysis of linear thermoacoustic theory, the influence of the relative position of two thermoacoustic cores on the onset temperature difference, pressure amplitude, and pressure ratio was studied by changing the relative position of two thermoacoustic cores. The results showed that the starting temperature of the two-stage loop traveling-wave thermoacoustic engine decreased first and then increased as the two thermoacoustic cores approached from the central symmetrical position. When the length ratio of the resonant tube between the two thermoacoustic cores was 1 to 3.5, the minimum starting temperature difference of the system was 59.6^oC (the working medium was N₂ and the inflation pressure was 2.5 MPa). Under the same temperature difference, the system had a larger pressure amplitude and pressure ratio at the position where the length ratio of the resonant tube was 1 to 3.5 compared with other positions.