基于声学法测温的声波飞渡时间研究

声波飞渡时间的准确测量是声学法测温中影响温度场测温准确性的主要因素。采用互相关分析法计算单一频率声波信号及宽带频率声波信号的声波飞渡时间，仿真结果表明宽带频率信号由于具有较强的抗噪能力在计算声波飞渡时间时不受声波信号周期、信号延时时间等因素的限制，可用于工程实践。同时采用频率为40kHz的正弦波超声波探测器在均匀温场条件下对超声波信号的衰减程度进行试验研究，试验结果表明40kHz的正弦波超声信号在不经过放大处理条件下，其可测温场的距离仅为160mm。

Study of Acoustic Travel-time Based on Acoustic Temperature Measurement Method

The accuracy of acoustic travel-time measurement is the main factor influencing the temperature measurement accuracy of temper-ature field in the acoustic temperature measurement method. The cross-correlation analysis is used to calculate the acoustic travel-time of single-frequency acoustic signals and broadband-frequency acoustic signals. The simulation results show that, thanks to strong noise immunity, the broadband-frequency acoustic signals are not restricted by periods or delay time of acoustic signals when calculating the acoustic travel-time, and can be used for engineering practice. In the uniform temperature field, the ultrasound detector of sine wave with a frequency of 40 kHz is used to test the ultrasonic signal attenuation. The test results show that, without amplification processing, the ultrasonic signal of 40 kHz sine wave can be used in the temperature fields with the measuring distance of only 160 mm.