Stagnation point heat transfer in superorbital expansion tubes

A calorimeter heat transfer sensor was designed and calibrated for use in blunt body superorbital expansion tube experiments. The sensor measures very high heating rates (~200 MW/m) in erosive flows of as little as 20 us duration. Data reduction techniques were established and calibration experiments performed to verify that the data reduction techniques are applicable for the manufactured sensor. Temperature signals for this gage can be transformed into heat transfer by differentiation as for a thin skin calorimeter. Experiments were performed in The University of Queensland’s XI and X2 expansion tubes to verify that meaningful data can be obtained with the sensor. Some sensors were coated with a glass layer to investigate catalycity phenomena. Measured heat transfer rates for the glass covered sensors were 40- 60% lower than that for the bare sensors. Heat transfer rates between 25 MW/m and 115 MW/m were recorded during these experiments