COMPUTATIONAL INVESTIGATION OF SHOCK-ENHANCED MIXING - APPLICATION TOCIRCULAR CROSS-SECTION COMBUSTOR

A computational investigation of shock-enhanced mixing applied to circ ular cross section combustors is presented. In a circular cross sectio n combustor, there are shock wave intersections at the center axis tha t produce adverse effects on mixing characteristics. The purpose of th is investigation is to analyze the adverse effects due to the shock wa ve intersections and to develop new combustor geometry minimizing the adverse effects and improving the mixing characteristics. Three-dimens ional Navier-Stokes equations are used to calculate the motion of the mean flow. A k-omega turbulence model is used to calculate the turbule nt viscosity. It is shown that, in a circular cross section combustor, the shock waves intersecting at the center axis reduce the strength o f the longitudinal vorticity and push the fuel downward. A change in t he shape of the cross section of the combustor to an octagonal cross s ection results in a reduction of the adverse effects and an improvemen t of the mixing characteristics.