Transverse Jet Mixing and Combustion Experiments in the Hypersonic Shock Tunnel T5 at GALCIT

For ground simulation of the flows that occur in SCRAM-Jet propulsion of hyper-velocity vehicles in which the hydrogen fuel is used as a coolant, it is essential that not only the enthalpy and pressure of the air flow, but also that the pressure and speed of the hydrogen be reproduced. Both can be achieved in the free-piston shock tunnel T5 together with the new small, combustion-heated hydrogen injection shock tunnel at GALCIT. Critical elements that need to be examined are the combustion efficiency and the turbulent mixing rate, especially at the unavoidable zero-shear condition, where the fuel and air speeds are the same. Results are presented from tests with a simple configuration consisting of a rectangular duct in which the injection system was mounted flush with one of the walls. The conditions cover a range of pressures from low values chosen to match previous experiments with the same duct from the HYPULSE expansion tube facility at the General Applied Sciences Laboratory, to values corresponding to the conditions closer to those in a real SCRAM-Jet engine.