Alternate Scramjet Fuel Modeling and Evaluation

The innovation is demonstrating how the addition of aluminum particles to hydrogen fuel, for a hypersonic scramjet, can enhance overall performance while reducing volumetric fuel storage requirements. In Phase I, preliminary “one-way” Al burn rate models were formulated, relevant at kinetic-controlled (small nano) and diffusion-controlled (10μm and above) limits. In Phase II, extended models will be developed that include Al equilibrium and dissociation chemistry and condensation modeling, and, that permit transitioning between the two limits as a function of particle size and surrounding conditions. Validation and unit problem fuel injection studies will be performed to “fine-tune” the extended models and assess their performance in a scramjet environment. Upgrades to the CFD codes will be performed to ensure that particle burn, turbulent dispersion, and wall interaction effects are accurately modeled. Genetic optimization techniques will be used to ascertain optimal fuel injection patterns with Al particulates, which can differ from the patterns used for gaseous fuel injection. Full propulsive flowpath simulations will be performed with Al particles added for Mach 10 axisymmetric and inward turning scramjets of current interest to the Army. Alternate hybrid fuel concepts will also be investigated such as Al/Mg and new composite particle concepts.