Accuracy Evaluation of Surface Temperature Profiling by a Laser Ultrasonic Method

Accuracy in measuring surface temperature distributions by a laser ultrasonic method is examined. Surface temperature distributions of an aluminum plate whose single side is heated up to 110 °C are estimated by the inverse analysis coupled with surface acoustic wave (SAW) measurements, and the results are compared with those measured by an infrared radiation method. A random fluctuation in the temperature estimated by the ultrasonic method is observed and decreases with an increase in the distance from the heating area. The standard deviation in fluctuation is estimated to be about 2 °C at the heating area. Furthermore, the systematic errors in the temperature estimation due to the deviations in the temperature dependence of SAW velocity and thermal diffusivity are investigated. It is found that the temperature dependence of SAW is an important factor affecting the systematic error, but the influence of the deviation in thermal diffusivity is negligible.