电磁超声法测量结构内部温度场的试验研究

Experimental Study on Sensing the Internal Temperature Distributions of Structures by Electromagnetic Ultrasonic

为实现结构内部温度场的无损、实时与高精度探测,研究设计一种可非接触式测量的电磁超声测温原理性试验系统。通过检测超声波回波信号在结构内部传递过程中波速的变化,根据热/声耦合理论,采用基于灵敏度法的温度场重建技术实现了对超声传播路径上温度非均匀分布状态的测量。基于钢试件的标定试验、稳态传热试验和瞬态传热试验,对超声测温系统及灵敏度测温方法的可靠性和准确性进行了试验研究。试验结果表明,采用灵敏度法的超声测温技术,结合无损非接触式探测的电磁超声方法,能够有效测量结构内部稳态/瞬态温度场分布状态,具有重要的工程应用价值。

The nondestructive,real-time and high precision detection of internal temperature field in a structure is one of the most important problems in the engineering and scientific experiments,an equipment of noncontact thermometry by electromagnetic acoustic technology is presented.Based on temperature dependence of acoustic velocity propagating through heated materials,internal temperature field can be detected by the sensitivity method.Calibration,steady state and transient state experiments are referred to validate the feasibility and reliability of the presented method.Results reveal that internal temperature gradient and its variation estimated by the method combined electromagnetic ultrasonic and sensitivity method agree well with the measured values using thermocouples installed in the steel,which can be helpful for various fields of science and engineering.