April 15, 2019: Large-Eddy / Reynolds-Averaged Navier-Stokes Simulations of Scramjet Combustor Flowfields

 

Abstract: Combustion processes within high-speed engine concepts (scramjets, ramjets) are often affected by strong compressibility effects, high turbulence intensity levels, finite rates of reaction, incomplete mixing, and core-flow blockage due to growth of viscous layers. Large-eddy simulation (LES) techniques offer several advantages over state-of-the-practice Reynolds-averaged Navier-Stokes methods in capturing these interactions, as they are able to directly capture larger turbulent structures and their corresponding effects. Since molecular mixing and combustion take place at the unresolved subgrid scales, there is still a need to model the effects of reactivity as expressed at the resolved scales. This talk surveys efforts undertaken at NCSU to model scramjet combustion processes mapped experimentally at the University of Virginia, considering both facility-specific influences and large-scale interactions among engine components. Numerical methods and physical modeling strategies will be discussed initially. Calculations involving non-premixed hydrogen-air combustion will then be described, followed by a discussion of pre-mixed and partially-premixed ethylene-air combustion during dual-mode scramjet operation.

 

Bio: Dr. Jack R. Edwards holds the Angel Family Professorship of Mechanical and Aerospace Engineering at North Carolina State University. Dr. Edwards received his B.S (1988), M.S. (1990) and Ph.D (1993) degrees from NC State and joined the faculty in 1994. He is an expert in computational fluid dynamics algorithm development, modeling of turbulent flows, and modeling of reacting and multi-phase flows. His current research thrusts include large-eddy simulations of turbulent combustion within high-speed aero-propulsion devices, unsteady aerodynamics, contaminant transport due to human motion, supercritical fluids, multi-phase flows, and GPU-based high-performance computing. He is the author or co-author of over 200 technical publications, and his research efforts have been supported by AFOSR, ARO, ONR, U.S. EPA, DARPA, DTRA, NSF, Sandia National Labs, and AFRL, among others.