稳态传热条件下的结构温度场和厚度同时测量方法研究

Method for Simultaneously Sensing the Internal Temperature Field and Thickness of Solid Structure under Steady Heat Conduction Condition

同时预测结构内部温度场和厚度对定量化评估油气管道等高温石化设备的安全可靠性有重要意义。采用增大初始时间和时间步,建立稳态传热条件下基于热/声耦合分析的超声同时测厚测温模型。采用超声回波法和热传导反问题分析方法相结合,将结构内部温度场的预测转化为等效热边界条件的反演和热传导正问题的计算问题,发展一种同时测量结构厚度和内部温度场的方法。研究表面,不仅避免了参数识别中输入信息不足带来的矩阵奇异问题,而且反映了波传播路径上由于温度不同所带来的声时累积特性,可有效提升稳态传热条件下超声同时测温测厚的准确性。试验验证可行性和可靠性,不同采样点数、热边界条件和试件厚度等算例分析也表明了该方法有很好的抗噪性。

By increasing the initial time and time step in analysis of heat conduction,an ultrasonic model under steady heat conduction condition is established to simultaneously sense thickness and internal temperature field based on thermo-acoustic coupling analysis.By using ultrasonic echo method and inverse heat conduction analysis,the estimation of internal temperature field of structure is transformed into the inversion of equivalent heat boundary condition and the calculation of normal heat conduction problem.This not only avoids the matrix singularity problem caused by insufficient input information in parameter identification,but also reflects the accumulation characteristics of ultrasonic transition time caused by different temperature in the wave propagation path,which can effectively improve the accuracy of simultaneous temperature and thickness measurement under steady heat conduction conditions.The feasibility and reliability of the presented method are verified by experiments.An extensive parametric analysis of different sampling points,thermal boundary conditions and specimen thickness also shows that the method has good noise resistance.