The innovation proposed here is a computational framework for high performance, high fidelity computational fluid dynamics (CFD) to enable accurate, fast and robust simulation of unsteady turbulent, reacting or non-reacting flows involving real or ideal fluids. This framework will provide a state-of-the-art unsteady turbulent flow simulation capability by laying the foundation for the incorporation of Hybrid RANS-LES (HRLES) methods which are a blend of Reynolds Averaged Navier-Stokes (RANS) and Large Eddy Simulation (LES) approaches. This design and analysis tool will be built on a currently existing solver called Loci-STREAM which has been developed by the proposing firm under funding from NASA over the last four years. The work proposed here will result in a state-of-the-art design and analysis tool to enable the accurate modeling of small valves, turbopumps, combustion devices, etc. which constitute critical components of versatile space propulsion engines with deep throttling capability as part of NASA's Vision for Space Exploration Mission. Of particular relevance to NASA, this design and analysis tool will provide improved understanding and quantification of the time-varying, reacting flow environments in the thrust chamber assembly of space propulsion engines.