High-Speed, Efficient, and Reliable Air-Breathing Hypersonic Propulsion: Experiment, Computation, and Analysis

Abstract

Air-breathing hypersonic propulsion system can make vehicle flying at Mach number 4~7, or four ~ seven times the speed of sound. It is expected to evolve into missiles, space access, and civilian plane transportation. The engine used in this propulsion system is supersonic combustion ramjet (scramjet). Because the SCRAMJET uses air from the atmosphere as the oxidizer to combust fuel, is does not require the liquid oxygen, which is needed for rocket propulsion. That means vehicle powered by scramjet can have a larger effective play-load and an affordable flying cost compared with rocket or space shuttle. Reliable combustion organizing technology is demanded for the scramjet with fixed geometry to achieve ignition, combustion and flame stabilization. In the present paper, an ethylene fueled scramjet model is tested in the pulse combustion wind tunnel at CARDC (China Aerodynamic Research and Development Center). The experiment inflow condition simulates the flight Ma 5.5. The gaseous ethylene is ignited by pilot flame of hydrogen. A single cavity accessed in the model upper wall is employed to facilitate combustion and stabilize flame. The performances of combustion are extracted from measured wall pressure. The physic details are investigated by CFD (Computation Fluid Dynamics) using the AHL3D software, which is developed by CARDC. The flow-field structure, combustion zone and the distribution of reactants and products are discussed intensively. Taking the isolator undisturbed length, thrust, fuel specific impulse as performance parameters, different fuel injecting schemes are compared and analyzed. Finally, an engineering -feasible combustion organizing method is put forward.