声速法温度场重建接收信号幅值影响分析

Analysis of the influence of received signal amplitude on acoustic temperature field reconstruction

为研究声速法接收信号幅值的变化对温度场重建的影响,基于声学测温法开展了热校准风洞模拟试验,成功模拟了航空发动机燃烧室出口的温度场重建。首先从接收到的信号数据中提取特征,建立特征矩阵,用以反馈信号幅值的变化;然后,基于采集到的信号数据,通过最小二乘法进行温度场重建;最后,通过比对不同特征矩阵下温度场重建的实际效果,分析声速法采集的信号幅值的变化对温度场重建的影响。通过试验验证可知:接收信号幅值越大,重建温度场的均方根误差越大,当幅值大于理论值40%时,均方根误差大于理论值14.38%;接收信号幅值越小,重建温度场的最大相对误差越大,当幅值小于理论值40%时,最大相对误差大于理论值44.3762 K。本文的研究对推动声学测温技术在航空发动机燃烧室出口温度场测试领域的发展起到促进作用,具有重要技术借鉴价值。

In order to study the effect of the variation of the received signal amplitude of the acoustic velocity method on the temperature field reconstruction, a thermal calibration wind tunnel simulation test was conducted based on the acoustic thermometry method to successfully simulate the temperature field reconstruction at the exit of an aero-engine combustion chamber. Firstly, features are extracted from the received signal data and a feature matrix is established to feedback the change of signal amplitude. Then, based on the collected signal data, the temperature field reconstruction is carried out by the least squares method. Finally, the effect of the change of signal amplitude on the temperature field reconstruction by the acoustic velocity method is analyzed by comparing the actual effects of temperature field reconstruction under different feature matrices. Through experimental verification, it can be seen that: the larger the received signal amplitude is, the larger the root mean square error of the reconstructed temperature field is, when the amplitude is 40% greater than the theoretical value, the root mean square error is 14.38% greater than the theoretical value;the smaller the received signal amplitude is, the larger the maximum relative error of the reconstructed temperature field is, when the amplitude is 40%less than the theoretical value, the maximum relative error is 44.3762 K greater than the theoretical value.The research in this paper has an important technical reference value to promote the development of acoustic temperature measurement technology in the field of aero-engine combustion chamber outlet temperature field testing.