Influence of Mesh Parameters and Turbulence-Chemistry Interactions on Wave Mode Prediction in Rotating Detonation Engines

The influence of spatial discretization, mesh refinement, and turbulence-chemistry interactions (TCI) on wave mode dynamics and heat release is studied by performing full-scale 3D nonpremixed reacting flow simulations of a rotating detonation engine (RDE). A total of seven cases were simulated for a single wave mode experimental condition. A second-order Roe flux-difference splitting (FDS) scheme and a third-order monotonic upstream-centered scheme for conservation laws (MUSCL) were used to study the influence of spatial discretization on wave mode formation. Five different base mesh sizes in the detonation region (0.6 mm, 0.45 mm, 0.35 mm, 0.3 mm, and 0.25 mm) were used to study the influence of mesh refinement on wave mode dynamics. Lower orders of discretization and coarser mesh sizes led to greater number of spurious waves, which was attributed to the increase in numerical dissipation/artificial mixing. The wave number and direction were strongly dependent on the mesh parameters. Apart from refinement, inclusion of TCI through the partially stirred reactor (PaStr) model led to the dissipation of spurious waves. Finally, it was shown that including TCI in nonpremixed RDE simulations significantly reduces the mesh requirement compared to finite-rate chemistry with no TCI.