Study Of Acoustic Temperature Field Measrrement System Based On PCI-4472

As a non-contact, non-invasive temperature measurement method, acoustictemperature field measurement is suitable for the atmosphere, silos, blast furnaces andocean areas. In this paper, the principle of acoustic temperature measurement is introducedsystematically，and gives an overview of its development status at home and abroad. Anacoustic temperature field measurement system which can simultaneously acquire16channel acoustic signals using two dynamic data acquisition card PCI-4472is designed.In this paper, two time delay estimation algorithms based on correlation andthird-order cumulants one-dimensional slice are designed. And two algorithms areprocessed by up-sampling technology. The proposed algorithms are simulated in MATLAB,under conditions of noise with low related coefficients, all algorithms can get accuratevaluations. As correlation coefficients rising and SNR lowering, basic cross-correlationalgorithm is invalid. Third-order cumulants algorithm has a good ability against noise withhigh correlation coefficient. It can be used in high correlation coefficient condition. Up–sampling technology can improve the equivalent acoustic signal sampling rate, and makethe results more stable.In the laboratory,16groups of speakers and microphones are arranged in the cube todetect the temperature field of1m×1m×1m space. The system tskes LabVIEW as itssoftware design platform. By calling MATLAB script, processes of sound data acquiring,sound travel time calculating, temperature field reconstruction can be carried outcontinuously. As the noise in laboratory is with high SNR and low correlation coefficient,correlation algorithm can get accurate acoustic travel time and temperature field.Third-order cumulants algorithm is not so stable, but after up-sampling, the results areimproved. Putting a electric furnace underlying central position to detect systemperformance of reconstructing the temperature field with hot spot. The reconstructionresults show hot spot position consistent with the furnace position and the hot spottemperature changes with the heating time, but the reconstruction temperature of hot spot value is lower than the actual value. Comparing with the temperature field reconstructionresults using different acoustic path choosing method. The three methods are a total of92effective paths after removing edges,64effective paths after removing the four sides andedges, and32effective paths after removing the six faces path. Three kinds of pathselection method can get accurate reconstruction results of the average temperature field,of which result error of32effective acoustic paths is the largest. When reconstructing theuneven temperature field,92effective paths should be chosen.