| The detection of the temperature field is very important in scopes of researches, the agricultural and industrial production and daily life. However, the measurement of the temperature field is so complex that the conventional methods can not meet the actual demand. Because of easy maintenance, large-space, non-contact, real-time continuous and a broader measuring range, acoustic method has characteristics of satisfying the requirements of detecting online in industrial productions and scientific investigations, especially in the high temperature and extreme thermometric environment, this method bears more advantages and characteristics that traditional methods can not compare. As a research subject,"Acoustic Measure method and technology of Gas Medium Temperature Field",which is based on actual application and requirement has a definite pertinence and engineering background, it accelerated the interior research pace of this area, and laid a solid foundation for acoustics thermometry and technology to practice as soon as possible.The basic theory of gas medium acoustic thermometry:the relationship of single valued function during acoustic transit speed and medium temperature. The concept of gas medium temperature field acoustic:according to the geometric shape of temperature field area to be tested, decorate several acoustic wave emission/receiving sensors around it, built-up several independent acoustic wave travel line; According to a definite way divided the area to be tested into several son temperature regional, in a measurement cycle, according to the order opening and closing the launch/receiving sensor, then we could measure the flying time of acoustic wave along each path; Put the multiple acoustic wave value time and relevant known parameters surveyed into temperature field inversion reconstruction program, then we could get the average temperature of every son temperature regional; Finally, take the average temperature of every son temperature regional obtained as center point temperature of this area, then use the interpolation algorithm to get the temperature distribution situation of the temperature field to be tested.This paper adopted inversion reconstruction program based on least-squares algorithm, get the right temperature field distribution, and make the measurement error controlled in a certain range, this shows that the reconstruction method of temperature field based on least-squares algorithm is correct, advisable, it meets the actual demand of temperature field acoustic measurement, at the same time also simply, speedily etc; The theoretical analysis indicates that the acoustic wave flying time accurate measurement is the most important factor that affects temperature field acoustic (inversion) measurement accuracy, therefore, we brought up a measuring method of acoustic wave flying time named "burst normalization threshold method" based on "the method of time difference", it solved the effect of acoustic wave emission/receiving sensor delay oscillation, improved sound velocity measurement precision in a quantity degree, and guaranteed the measurement accuracy of temperature field acoustic (inversion); In the light of two-dimensional circular temperature field, it set up acoustic measurement system and accurate pointing system, and we proceed actual measurement experiment of temperature field, both measured result is very identical The result proved that the temperature measuring system acoustics is correctly and reliable, the "burst normalization threshold method" measurement method we proposed is effective;3D temperature field acoustic measurement computer simulation results show that sound ray "buckling effect" is one of the key elements that affect temperature field acoustic measurement reconstruction accuracy;, after considered sound ray buckling effect, the quality of temperature field reconstruction has been greatly improved; Under the2D square single asymmetric temperature field, three sensor quantity and four sensor layout mode is researched by emulation, it show that the temperature acoustics (inversion) measuring accuracy based on the least squares method is not only with the number of sensors, but also by the impact of the sensor arrangement. |
