Research And Implementation Of Temperature Field Measurement Based On Acoustic Method

With the development of modern technology in industrial production,temperature field measurement gets more and more attention.But the conventional temperature measurement method is difficult to execute in practice for all kinds of reasons like limited area,non-real-time measurement,relatively short lifespan and so on.Acoustic temperature field imaging technology is widely used in temperature field measurement for its advantages of non-contact,high-precision,continuous real-time measurement,easy maintenance.In this dissertation,the fundamental principles and development of acoustic temperature measurement were introduced.And next simulation software of temperature field was coded based on MATLAB,in which the influence of original temperature fields,reconstruction algorithms,sensor distributions and mesh schemes were analyzed.Then acoustic temperature measurement platform was built to reconstruct two-dimension and three-dimension temperature fields.The mainly tasks are as follows:(1)The basic principle of acoustic temperature measurement was researched in this dissertation.Theoretical foundation of temperature field measurement was explained based on the least square method and the index-SVD method and mathematical expression of imaging algorithm was deduced.(2)Acoustic signal emission and acquisition circuit were improved on the basis of the former research.Signal control circuit was designed and hardware circuit acoustic temperature measurement platform was accomplished.(3)Boiler temperature field simulation system was created,which explored the influence of different imaging algorithms(interpolation algorithm,least squares algorithm and index-SVD algorithm),sensor distributions and mesh schemes.At last,experimental layout was determined.(4)For single-path acoustic thermometry experiments,influential parameters for experiment results were analyzed including signal passband,sample frequency sampling amount.Parabolic interpolation for generalized correlationwas was used to improve accuracy rate The results show that the average error rate is within 5%.(5)Feedback was added from upper computer to lower computer to complete information loopback and improve measurement accuracy rate by defining criterion.(6)Two-dimension and three-dimension temperature field were rebuilt based on acoustic temperature measurement platform and upper computer real-time GUI interface.The results showed that when temperature field of measured area changed,temperature field image detected in upper computer could change with it.