Phosphor Thermography for Global Heat Transfer Measurement in High-Enthalpy Shock Tunnel FD-21

The phenomenon of self-luminescence in high enthalpy flow field will have a serious impact on all kinds of optical measurement techniques, and make the effective information completely drowned. In this paper, a comprehensive filtering method based on the physical hardware and reference point image processing is established, and the phosphor thermography experiments of total temperature is 2700K and 4700K are carried out in the high enthalpy shock wave wind tunnel FD21 of China Academy of Aerospace Aerodynamic using the compressed corner shape. The experimental results show that the interference of the self-luminescence on the phosphor thermography increases with the total gas temperature. When the total temperature is 2700 K, the heat flux distribution of the compressed corner shape surface is obtained, and the peak value of heat flux on the wedge surface is accurately captured. The phosphor thermography is consistent with the measured results of thermocouple. When the total temperature is 4700 K, the strong self-illumination almost completely submerges the effective image information, and the experimental data is seriously distorted. In this case, more effective methods should be adopted to reduce the influence of self-illumination.