Temperature Field Detection Based On Acoustic Tomography Technology

In the boiler operation,the furnace temperature directly reflects the combustion condition in the furnace.Therefore,it is very necessary to measure the furnace temperature forjudging the combustion condition in the furnace,burning adjustment and improving the combustion equipment.Although the contact temperature measurement method,such as thermocouple,has the characteristics of intuitionistic and convenient,the contact temperature measurement will affect the temperature distribution and cause errors.Acoustic temperature measurement method based on acoustic tomography is a non-contact temperature measurement method with high accuracy,good real-time performance and wide measurement range.It has the advantages of strong resolution,high sensitivity and fast response,and it is capable of measuring temperature at high speed,high temperature and strong corrosiveness.Therefore,based on the theory of acoustics,this paper mainly studies the application of acoustics in the reconstruction of three-dimensional temperature field,and sets up a set of three-dimensional temperature field of ultrasonic measurement system.For acoustic temperature measurement,the measurement results are mainly influenced by two factors,accurate measurement of time of flight and reconstruction algorithm accuracy.This paper focuses on the study of reconstruction algorithm and time of flight measurement.At the same time,a ultrasonic measurement system of three-dimensional temperature field is built using acquisition card,ultrasonic transducer and other hardware and software such as MATLAB and LabVIEW.The selection of transceiver location and sound wave path are also studied in this paper.Firstly,the basic theory of acoustic temperature measurement is analyzed,and the measurement methods of flying time,the number and arrangement of ultrasonic transducers and the number of reconstruction meshes are discussed and selected.Secondly,we introduce four kinds of reconstruction algorithms,such as least square method and algebraic reconstruction method,and use these four kinds of reconstruction algorithms to reconstruct the three-dimensional temperature field.Thirdly,the ultrasonic measurement system of three-dimensional temperature field is introduced from the two parts of software design and hardware composition.Finally,the ultrasonic temperature measurement system is used to reconstruct the actual temperature field of uniform temperature field and non-uniform temperature field.The experimental results of temperature field reconstruction show that the ultrasonic temperature measurement system built in this paper can run stably and steadily,and the relative error of the uniform temperature field is less than 1.5%.