The Measurement Of Sound Travel-time In Acoustic Temperature Tomography

Recently temperature field measurement based on acoustic tomography is applied to measurement of furnace temperature, and developed rapidly. This paper introduce the technology of acoustic tomography, summarize the research of acoustic pyrometer inside and outside, expatiate the keystone of acoustic temperature field measurement, establish the whole scheme of acoustic temperature field measurement, and make sure to adopt the method of correlation function analysis to measure the travel-time of sound wave. This paper mainly discusses the key point of the acoustic temperature field measurement—The travel- time of sound wave.In this paper we separately use White noise and chirp signal as signal source, and apply simulate software MATLAB to research the time delay between the transmitted signal and the received signal. The correlation coefficient curves corresponding to different SNR, sampling number and sampling interval are analyzed and compared. The influences of these parameters to the precision of correlation measurement are discussed. The results of research indicate that the correlation measurement of delay time has good ability of anti-jamming with suitable sampling number and sampling interval when white noise or chirp signal is used as signal source.With White noise signal source and correlation function analysis, we design the acoustic temperature measurement system controlled by sing chip computer and implement the measurement of the travel-time of sound wave. The sound wave travel-time at different sound travel-distance is measured at a fixed temperature. The test results show that the relationship between the measured sound wave travel-time and the measured sensor's distance is linearity. The sound wave travel-time at different medium temperature is also measured at a fixed sensor distance. The test results indicate that when gas medium temperature is higher, the sound wave travel-time will be smaller, which accords with the relationship of gas medium temperature and velocity of sound. The preliminary test resultsprove that the signal source and the signal processing method adopted can implement the measurement of the sound travel-time and the average temperature on sound travel-path. The hardware and software design are also given in this paper.