Description: The innovation proposed here is a framework for the incorporation of high performance, high fidelity computational fluid dynamics (CFD) techniques to enable accurate and robust simulation of unsteady turbulent, reacting or non-reacting flows involving real or ideal fluids with practically useful turnaround times. The emphasis will be on a major improvement in efficiency and scalability of Loci-STREAM which is a CFD code already in use at NASA. The Loci-STREAM code is becoming more and more reliable for individual calculations; however, the overall computational performance of the code on the computer clusters employed by NASA is not sufficient for the tool to be used effectively in the design process given the complexity of the configurations being modeled by NASA engineers along with the large grid sizes used to model these configurations. The proposed work targets an order of magnitude improvement in performance of Loci-STREAM. The work proposed here will enable the efficient and accurate modeling of: (a) multiphase combustion in solid and liquid rocket engines, (b) combustion stability analysis (c) acoustic fields of space propulsion systems in near-ground operation, (d) launch pad-induced environments, (d) small valves and turbopumps, etc.

Benefits: The computational tool resulting from this project will have wide-ranging commercial applications. The Hybrid RANS-LES methodology can be used for a wide variety of engineering applications involving unsteady turbulent flows. The reacting flow capability can be used for simulating combusting flows in various industrial applications, such as gas turbine engines, diesel engines, etc. The real-fluids methodology can be used in a large number of industrial flow situations involving both chemically inert and reacting flows. With additions of multi-phase combustion modeling capability, the applicability of this tool can be further broadened.

The outcome of Phase I and Phase II research activities will be a powerful CFD-based design and analysis tool for propulsion engines at NASA. This tool will facilitate full rocket engine simulations, injector design, launchpad induced environment simulations, turbopump design, etc. Specific applications at NASA of this capability include: (a) design improvements of liquid rocket engine injectors, (b) modeling of multi-element injectors coupled with fuel and oxidizer feedlines and manifolds, (c) prediction of stability and stability margins, (d) design of acoustic cavities for combustion stability, (e) analysis of small valves and turbopumps, (f) prediction of loads during launch of new launch vehicle, (g) prediction of acoustic loads on rocket engine test stands, (h) launch pad modifications, (i) development of new launch facilities, (j) analysis of rocket engine exhaust plumes, (k) modeling of flow of liquids and supercritical fluids through piping system components such as valves and run tanks ,etc.