Research On Ultrasonic Temperature Measurement Method Using Structure Echo

For the temperature measurement of the inner wall of the transmission pipeline,the inner wall of the gun tube,the inner wall of the engine combustion chamber,and the outer surface of the aircraft waiting to be measured,it is not easy to directly measure the temperature of these surfaces with conventional temperature measurement techniques such as thermocouples,thermal resistance and radiation temperature measurement techniques.Therefore,the development of a temperature measurement technology that can be applied to the abovementioned surface has become one of the research directions of temperature measurement technology.This paper proposes an ultrasonic-based structural echo temperature measurement method.The method uses the special geometric structure of the temperature measurement target to obtain ultrasonic echo signals at different reflzection interfaces,and realizes the treatment based on the thermal dependence of the ultrasonic sound velocity in the medium and the temperature of the medium.Temperature measurement of the measuring surface.The heat transfer model of this method can directly obtain the temperature of the surface to be measured.A combination of theoretical analysis,numerical simulation and experimental verification is used to study the feasibility of ultrasonic structural echo method to measure surface temperature.This temperature measurement method has a certain degree of feasibility for non-destructive and non-invasive temperature measurement of the surface to be measured,but this method relies on the special geometric structure of the location to be measured and has certain limitations.This article has completed the following work:(1)Completed the construction of the experimental platform for the ultrasonic structure echo temperature measurement method,including: experimental specimens,ultrasonic time delay value measurement system,temperature measurement and control system,and selection of various instruments in the experimental platform.(2)For the ultrasonic shear wave echo signal,the cross-correlation function method and interpolation method are used to calculate the time delay value of the echo signal;in order to solve the problem of aliasing of the longitudinal wave echo signal,a new anti-aliasing delay algorithm is proposed.Compared with the cross-correlation algorithm,this method has a smaller error,can accurately obtain the delay value of the two echoes,realizes the delay measurement of the nanosecond level,and ensures the temperature measurement accuracy.(3)The experimental parameter calibration and temperature measurement experiments were performed on the specimens using ultrasonic transverse waves and longitudinal waves.The experimental results show that the surface temperature obtained by the ultrasonic structure echo temperature measurement method is basically consistent with the actual temperature change in the overall trend.