Spatially Resolved Measurement of Surface Heat Flux Using Thermography Camera

Abstract

This paper presents an approach for the locally resolved determination of transient surface heat flux based on measured transient surface temperature data. The approach solves the inverse heat conduction problem by means of an experimental calibration approach. A system identification procedure is used to link local surface heat flux to the surface temperature distribution measured with an infrared camera. The surface resolved camera data allows to discretize the problem to a number of distinct surface elements. The application of the method is demonstrated on a ceramic matrix composite fin under a supersonic high-enthalpy air flow condition. The results show a strong spatial distribution of surface heat flux. The measurements demonstrate the expected steady state heat flux, whereas the temperature is by no means stationary, i.e. no thermal equilibrium is reached. The maximum heat flux is measured at the sharp leading edge of the fin, which is to be expected. Furthermore, a heat flux peak is identified which correlates with the impingement of an oblique shock wave.