Rocket Based Combined Cycle [RBCC] engines have the potential to improve the specific impulse of conventional rockets through the use of atmospheric air. Much of the improvement depends on the ability of the rocket and air streams to mix. This paper examines the ability of a novel inlet design called the exchange inlet to promote mixing within an axisymmetric RBCC engine. Rocket exhaust is injected in an annular pattern starting from a circular throat while drawing air towards the centreline. Numerical simulations are performed focusing on the rocket and air interaction within the engine. The entrained air conditions produced by the exchange inlet are shown to be uniform and avoid significant regions of separated flow around the rocket flowpath. Despite a large variation of flow properties across the entrance of the mixing duct due to the difference between the rocket and air streams, five diameters downstream the flow is shown to be well mixed. The variation in temperature at this distance is reduced by 65% while the rocket exhaust is shown to have spread across the entire exit area (as indicated by species massfraction).

Additional Metadata
Conference 47th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit 2011
Citation
Yuen, T. (Tommy), & Etele, J. (2011). Exchange inlet design for enhanced RBCC rocket-air mixing. Presented at the 47th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit 2011.