Research On Temperature Measurement System Of High-temperature Gas Based On Acoustics

Temperature measurement plays an important role in new technical research, industrialproduction and daily life. However, the measurement of temperature field is more complexsuch as measuring the temperature distribution of aeroengine combustion chamber andlarge-scale coal-fired power plant furnace. As the high temperature changes quickly and themeasured space is large, the traditional methods, such as thermocouple thermometer, cannotmeet the actual demand. Temperature measurement system based on acoustic thermometryhas many advantages such as large space of measuring object, easy maintenance, widetemperature range and non-contact, and it can continuously supervise the temperaturedistribution of temperature field in real time. The article researched the temperaturemeasurement system based on acoustic thermometry and mainly accomplished the followingwork:First, the fundamentals of acoustic thermometry were introduced, and a new time delayalgorithm was proposed, which combined the interpolation algorithm and cross-correlationtime delay estimation. The novel method improved the measuring precision.Then the paper designed elements of the temperature measurement system. Acousticsource is crucial in designing the system. According the actual demand and the characteristicsof acoustic source, Chirp Signal was chosen as the acoustic signal, the frequency sweep rangewas1~5kHz and signal period was0.5s. Besides, the signal was required enough strong sothat it could fly the measured space. Acoustic sensor used in this paper was made ofpiezoceram patches, which could resist high temperature, protect against moisture andcorrosion, and the acoustic performance was stable.The least-squares algorithm is the common reconstruction algorithm in acoustictemperature measurement system, which is a mature technology. In this paper, a new acoustictemperature reconstruction algorithm which based on radial basic function and singular valuedecomposition was used in the system. Then through compared with the two reconstruction algorithms, the influence factors of reconstruction were analyzed. At last, a revised model ofacoustic thermometry was proposed where the gas medium flowed rapidly, and discussing theadditional condition.The results of simulation and actual experiments demonstrated that the system designedin the paper was feasible. Compared with the least-squares algorithm, the radial basicfunction-SVD algorithm made the maximum relative error, average relative error androot-mean-square error respectively reduced by3.31%,0.67%and0.72%in temperature fieldreconstruction. Besides, the reconstruction quality was better when the temperature inmeasured space was complex, the errors reduced by1.11%,4.06%and7.05%. And the newmethod could describe the temperature distribution besides the boundary.