Review on the development of the free-piston high enthalpy impulse wind tunnel and its testing capacities

The free-piston high enthalpy impulse wind tunnel is one of the main ground testing facilities for the study of the high enthalpy flow, which is able to simulate the hypervelocity flow and is mainly categorized into two types as the high enthalpy shock wind tunnel and the high enthalpy expansion tube wind tunnel. After decades of development, the free-piston high enthalpy impulse wind tunnel can be used not only to study the complex aerodynamics thermodynamics and aero-optic of the aircraft under the hypervelocity free flow, but also to carry out research on technologies such as the free flight, the scramjet and the electromagnetic radiation measurement. The development process is summarized, focusing on the three stages of the basic theoretical research stage, the early construction stage and the practical development stage, in order to provide reference for the development of the large-scale free-piston high enthalpy impulse wind tunnel and its testing capacities.