Numerical investigation of transverse sonic injection in a non-reacting supersonic combustor

Efficient combustion and heat release in scramjet flows depend on effective mixing of the fuel in supersonic streams. Usually, transverse sonic injection in-stages are employed as one of the suitable means for efficient supersonic combustor design. Numerical simulations are carried out to study the mixing characteristics of staged sonic air injections in supersonic stream ( M = 2.07) behind a backward-facing step in scramjet combustor by solving three-dimensional Navier-Stokes equations along with K-ε turbulence model with a commercial CFD software CFX-TASCFlow. Computed results of the jet penetration and spreading show very good agreement with the experimental values and the results of other computations. A good overall match has been obtained between the experimental values and the computation for various flow profiles at various axial locations in the combustor. However, the values differ in the near-field region at the injection plane. The assumed uniformity of the flow-field properties at the injection orifice and/or the inadequacy of the turbulence model considered in this study is conjectured to be the cause of the difference.