Experimental Study the Measurement of Acoustic Wave Flight Time under Strong Noise in the Boiler

The measurement accuracy of acoustic wave flight time is the key to achieve high-precision temperature measurement of acoustic method under strong noise in the boiler. In order to obtain accurate acoustic wave flight time in the acoustic temperature measurement of power station boiler, we have studied the acoustic signal time delay estimation for the weak signal detection in strong noise environment. The noise of the furnace which is collected from a domestic power plant has been made spectral analysis and statistical analysis. And it shows that the furnace noise which focuses on the center frequency of 250-1000 low-frequency combustion noise was Gaussian-like distribution. This paper introduces the measurement of flight time based on the correlation function in the acoustic pyrometry. The realization principle of measurement method has been detailed. Through making a specific analysis with field data it is concluded that direct correlation method of acoustic flight time measurement has high precision and strong anti-interference ability, therefore, it is applied to measure the acoustic time of flight in the industrial environment.