Zeng Lei

Research on parameter estimation in ultrasonicmeasurement of internal transient temperature distributions

A new reconstruction method of internal unsteady temperature distributions in solid structure using ultrasonic thermometry technique is presented in this paper. This method mainly consists of a joint of heat condution caculation and an inverse analysis for boundary parameter estimation using ultrasonic time of flight by Conjugate Gradient method. The principle for internal temperature sensing is based on temperature dependence of the velocity of the ultrasonic wave that propagates through solid material. Simulation and stability analysis are made in which classic function form of heat flux is estimated to illustrate accuracy, as well as factors of influencing quality of this reconstruction method. Validation experiments with a steel plate whose single side is heated by a heater and then cooled down by water are refered. It is verified that the temperature gradient and its variation estimated by this method agree well with the measured values using thermocouples installed in the steel. The results demonstrate that the method presented in this work is a promising means for high accurate rebuilding internal unsteady temperature distributions in solid structure.