| In order to improve the understanding of particle vitiation effects in hypersonic propulsion test facilities, a quasi-one dimensional numerical tool was developed to efficiently model reacting particle-gas flows over a wide range of conditions. Features of this code include gas-phase finite-rate kinetics, a global porous-particle combustion model, mass, momentum and energy interactions between phases, and subsonic and supersonic particle drag and heat transfer models. The basic capabilities of this tool were validated against available data or other validated codes.;To demonstrate the capabilities of the code, and to provide initial insight into the effects of various particle laden flows on ignition, a series of computations were performed for a model hypersonic propulsion test facility and scramjet. Parameters studied were simulated flight Mach number (Mach 5, 6, and 7), particle size (10, 100, and 1000 micron diameters), particle mass fraction (single particle and 1%) and particle material (alumina and graphite). For the alumina particles, it was found that the presence of particles up to 1% mass fraction had very little effect on the gas phase, even though only the 10 micron particles closely followed the gas flow velocity and temperature. With the graphite particles, the 10 micron particles were either quickly quenched, or were quickly consumed, depending on the gas temperature. As the particle size was increased to 100 microns, the particles did not quench, but were still typically 20 consumed within the model test facility. For the 1000 micron particles, combustion was diffusion limited, so particle and gas temperature had little effect on the combustion rate. When the particle mass fraction was increased to 1%, the main change was the addition of significant heat release. In those cases where low graphite reaction rates were observed for single particles, the increase to 1% mass fraction had very little impact.;Hydrogen/vitiated air ignition delay calculations for the 1% mass fraction of graphite particles cases showed significant decreases in ignition delay in cases where higher graphite combustion rates were observed. Further calculations showed that this was due primarily to increased combustor inlet temperature, not the gaseous or solid vitiate species present in the flow. |
