Investigations On Acoustic Detecting Techniques And Simulation Of 3-D Temperature Field

The detection of the temperature field is very important in scopes of researches, the agricultural and industrial production and the daily life. However, the measurement of the temperature field is so complex that the conventional methods can not meet the demands of production and living. As a new-style temperature measuring method, the acoustic method is much faster and with a high precision as well as a broader measuring range. It can satisfy the requirements of measuring accurately and controlling online on the temperature field in industrial productions and scientific investigations, especially in the inclement condition of high temperature.This subject emphasizes on the investigation of acoustic measuring methods and algorithm to temperature fields. It has implemented the reconstruction and simulation of the 3-D temperature field by acoustic method. At first, an analysis on the realistic importance of the temperature field monitoring has been given, as well as the fundamental and the development of acoustic thermometry has been introduced in the paper. Then, because the acoustic wave refraction in temperature gradient field is an important factor that affects the reconstructing accuracy of temperature field by acoustic method, this subject researches deeply on the principle and algorithm of ray tracing. There are total three common algorithms of ray tracing in this paper. In addition, the ray tracing and simulation of the true propagation paths of 2-D and 3-D acoustic wave by forward deploying triangle and deploying regular tetrahedrons are carried out especially. The principle and implementation of some familiar reconstructing algorithms on complex temperature field by acoustic methods is also presented. In order to improve the stability of the solution, the regularization method can be used to convert an ill-posed problem into a well-posed problem. At last, an investigation on the reconstructing mechanism, methods and relational algorithms of 3-D temperature field with acoustic pyrometry is made. Furthermore, an elementary discussion on key points in the reconstruction is given. On the ground of these, the least-square regularizing algorithm for reconstructing 3-D temperature field is presented. In this part of the paper, a comparison and analysis have been made on the reconstructing quality of the temperature field on different presuppositions, including whether considering the acoustic wave refraction or not, the different amounts and locations of sensors, etc. The analyzing result shows that it will improve the reconstructing accuracy deeply with a modification and compensation to the acoustic wave in the reconstructing process. It also shows that the increase of the amount of acoustic sensors can improve the reconstructing accuracy to some extent. They are consistent well with the theoretical estimate.