Temperature monitoring on a plasmatron experiment by pyroreflectometry

Abstract

In the domain of re-entry materials submitted to plasma heating, the temperature reached by the samples is a prior information. In this paper, the capability of pyroreflectometry [1] to measure the true surface temperature of a C-SiC sample exposed to the high-enthalpy plasma of the Plasmatron facility [2] is assessed. This study includes general thoughts about the influence quantities on the measurement : emissivity variations during the experiment, plasma emission and windows transmission. We propose then a method called pyroreflectometry, and we calibrated the system in a way to solve the three previous problems. In the first part, the Plasmatron facility and the pyroreflectometry method are presented. Then, the radiative properties of the scene are retrieved and/or measured by spectrometry. Finally, the results of pyroreflectometry on the Plasmatron facility are displayed and commented. We conclude that this first instrumentation is very encouraging, the true temperature of the sample is retrieved and the ablation signature through the emissivity variations is appearing.