Abstract: A novel calorimeter suitable for long time and medium/low heat flux (5~500 kW/m2) measurement is proposed in this paper to investigate the aerothermodynamic problems induced by shock interactions in hypersonic low density flow. The calorimeter is designed by a way of air gap insulation to alleviate the lateral heat transfer, which approximates the one dimensional heat conduction and consequently extends its effective measuring time. Then, the fabricated calorimeters are calibrated to improve the accuracy of measurement. In order to validate the performance of the calorimeter, the calibration experiment and hypersonic low density wind tunnel experiment with a double cone model are carried out. The heat flux measured by the calorimeter is compared with the coaxial thermocouple results. The results show that the response time of the calorimeter is longer than that of the coaxial thermocouple; but for a larger heat flux, the measurement accuracy of the calorimeter is higher because the lateral heat transfer is greatly alleviated. The coaxial thermocouple has better performance in low heat flux (5~20 kW/m2) measurement with a larger signal to noise ratio (SNR). The research provides a measurement technique for the investigation on shock wave/boundary layer interactions in hypersonic low density wind tunnel.

Key words: Aerothermodynamics, Calorimeter, Shock wave/boundary layer interaction, Hypersonic flow