Design Of Ultrasonic Guided Wave Resonant Thermometer

With the development of modern society,accurate temperature measurement in ultra-high temperature environments has a wide range of application backgrounds and strong application requirements in special fields such as aerospace and nuclear power generation.At present,the main sensors that realize temperature measurement in industrial production are thermocouples,thermal resistances and radiation thermometers.With the increasing advancement of science and technology,various temperature sensors have achieved great improvements in performance,but there are limitations in use.For example,the sensitivity and accuracy of thermocouple sensors are very good,but it is difficult to work for a long time in high temperature environments;the temperature measurement conditions of radiation thermometer sensors are affected by environmental factors such as smoke,and it is difficult to achieve accurate measurement requirements in special environments.As a temperature measurement technology,ultrasonic temperature measurement has the advantages of high sensitivity and fast response.This paper designs an ultrasonic guided wave resonance thermometer based on the resonance method in the theory of ultrasonic temperature measurement to realize real-time measurement of the ambient temperature field.In this paper,based on the research on the principle of ultrasonic guided wave resonance temperature measurement,a resonant temperature sensor is designed and the parameter calculation of its key dimensions is studied.Combined with the characteristics of ultrasonic guided wave resonant temperature measurement,the overall design scheme of ultrasonic guided wave resonant temperature measuring instrument is determined,which mainly includes hardware system and software system.The hardware system includes a single-chip microcomputer control module,an ultrasonic transmitting module,an ultrasonic receiving module and an ultrasonic frequency self-tracking module,which realizes the transmission and reception of ultrasonic waves and the tracking of ultrasonic frequencies.The software system includes a microcontroller temperature measurement program and a human-computer interaction program based on serial touch screen,which can realize system parameter setting,frequency measurement and temperature display and other functions.Based on the completion of the resonant temperature sensor and ultrasonic guided wave resonant thermometer,the whole experiment platform of ultrasonic temperature measurement was built.The function relationship between the resonant frequency and the temperature of the resonant temperature sensor at 20℃～920℃ was obtained through calibration experiments.By analyzing the experimental results,the temperature resolution of the designed ultrasonic guided wave resonant thermometer is 0.21%,and the sensitivity is 0.05 kHz/℃.Finally,the uncertainty of the experimental results is analyzed to the effect of the possible errors in the experiment on the temperature measurement process.