Three-Dimensional Analysis of a Supersonic Combustor Coupled to Innovative Inward-Turning Inlets

Three-dimensional simulations are employed to examine the effect of inlet distortion and model fidelity with Reynolds averaged Navier-Stokes or large eddy simulation approaches for a generic circular cross-sectional supersonic combustor at a flight condition of Mach 6 and an altitude of about 24.2 km. To examine inlet distortion effects on combustion, frozen and finite rate chemistry simulations are performed on combustors connected to two different types of streamline-traced inlets (denoted "Scoop" and "Jaws") with the Wilcox k-ω turbulence model. For comparison, uniform inflow boundary condition to the combustor is also simulated. The metrics employed include qualitative assessments related to flow structure as well as quantitative values offuel combustion efficiency and thrust ratios. The results indicate a complex overall effect of distortion due to inlet design. For Jaws, the increased pressure loss associated with distortion is mitigated slightly by improved combustion efficiency and better thrust performance. The Scoop inlet has lower distortion and better recovery, but the combustion coefficient is lower than Jaws. In the second part ofthis study, finite rate chemistry results with unsteady Reynolds averaged Navier-Stokes are compared with those from large eddy simulation with an uniform inflow profile. Differences in transient processes include the manner in which large- and small-scale structures originate and evolve in the cavity recirculation and downstream regions. The finer details observed with the large eddy simulation model have significant consequences on the overall field, including the unsteady position of the shock structure arising from the interaction of the incoming flow with the cavity shear layer, combustion processes, and injection jet interactions.