Scramjet Combustion Student Projects

Professor Gustaaf Jacobs
Department of Aerospace Engineering and Engineering Mechanics,
San Diego State University
Phone: (619) 594-6074

The development of the X-51 has surged the development of scramjet technology at NASA and DoD. Fuel injectors play a decisive role in scramjets and have been subject to significant efforts at NASA Centers and AFRL. The design of fuel injectors determines the fuel-air mixing which has a significant impact on the quality of combustion. Poor combustion can lead to flame instability, acoustic instability, and increased emission of pollutants among others and degrades the overall combustor performance. In scramjets used in hypersonic air-launched vehicles fuel injectors typically inject gaseous or liquid hydrocarbon fuels in a supersonic cross-stream. Challenges in the design of these injectors include ignition, a stable flame-holding, a drag overhead and the deep penetration of the fuel into the flow. Many of these challenges are directly related to the complex flow structures and consequent mixing levels close to the injector. Based on recent breakthrough Lagrangian theories developed at SDSU in collaboration with MIT and using our high-fidelity in-house Direct Navier-Stokes and LES solvers, we aim to identify distinct Lagrangian flow structures upstream of the fuel injectors and develop a new theory that enables the quantitative analysis of the dynamic mass and fuel flows into the flame zones. We further seek to control these flow structures by local plasma heating to obtain desired fuel-air mixing levels and ignition temperatures.