Modeling of Gardon Gage Heat Flux Sensor Under Aerothermal Environment

Abstract

Intense aerodynamic heating on launch vehicles renders the thermal protection systems (TPS) design critical. Accurate flight measurement of aerothermal heating is necessary to validate the models used in the systems design process. The current work studies the thermal behavior of a circular foil, copper-constantan transducer, mounted flush with the surface of the payload fairing of a launch vehicle for heat flux measurement. The transducer functions on the principle of Seebeck effect in the presence of a temperature gradient across the circular constantan foil and the surrounding copper sink. The use of circular foil heat flux transducers to measure convective heat flux, as encountered in flight, is observed to be associated with uncertainty in results. The study comprises of a Gardon gage heat flux sensor modeled in ANSYS, subject to convective environment encountered in a typical launch vehicle trajectory. A methodology is developed to derive sensor-measured heat flux from the thermal response of the model. The results are found to be in agreement with the flight measured values.