Reacting RANS Simulations of a Dual-Mode Ramjet Combustor: A Code Credibility Study

摘要

Reacting Reynolds-Averaged Navier-Stokes (RANS) simulations have become an integral part of the design and analysis of dual-mode ramjet combustors (DMRJ). It is expected that solving the same equations on a sufficiently resolved grid should produce results that are independent of the flow solver used. In practice, however, slight differences in model implementation and numerical differences between the solvers might have a non-negligible influence on the results. For this study, five solvers: CFD++, Kestrel, Loci/CHEM, US3D, and VULCAN were chosen based on the authors' expertise to verify that each code behaves similarly for a generic, round DMRJ combustor. To verify turbulence model implementation within each solver, the Menter baseline two-equation model (BSL) is utilized to simulate a canonical axisymmetric transonic bump. Each solver is then used to simulate the round scramjet combustor housed in Research Cell 22 of AFRL's High Speed Systems Division. A grid refinement study was conducted using each code. Results comparing wall pressure data between the five solvers are used to define the spread of results. The spread in shock train position is approximately one quarter of the isolator duct height in the finest resolution simulated. This is considered reasonable agreement as the differences between the five solvers is shown to be negligible compared to the differences observed when alternative turbulence models are selected.