Surface Heat Transfer Measurement by Immersed Temperature Sensor: Calibration of Sensor depth and material properties

A transient surface heating or cooling process of a solid probe is considered using a temperature sensor submersed in the probe. On the basis of this measured temperature the surface temperature and surface heat flux density are calculated by inverse process modelling. For solving this inverse problem the sensor depth as well as the thermal material properties have to be known precisely in order to obtain accurate results. For a high accuracy, the sensor depth has to be as small as possible (ideally some tenth of mm) and thus cannot be determined geometrically with sufficient accuracy during the probe assembly. Thus two calibration procedures to determine (or validate) both sensor depth and material properties of probes before or between heat transfer measurements are presented in this contribution.