Combustion shock tunnel and interface compression to increase reservoir pressure and enthalpy

This paper discusses the production of hypervelocity-hypersonic flows in a combustion shock tunnel operating in the equilibrium interface mode. In this mode of operation, the additional compression provided by the approaching interface is used to obtain higher pressures and temperatures, as opposed to the reflected method. A computer code was developed to model the operation of a shock tunnel in the equilibrium interface condition. All the calculations were made for the Rensselaer Polytechnic Institute (RPI) 1-22-m-diameter Combustion Driver Hypersonic Shock tunnel. The major drawback of the interface compression technique, which is the contamination of the driven gas by the driver gas, was overcome through the utilization of a small volume buffer region separating the two gases. Numerical results indicate that the RPI facility will be able to generate reservoir temperatures of the order of 20,000 K and reservoir pressures of the order of 30,000 psi. These reservoir conditions can be used to produce test section Mach numbers of 35. (Author)