Abstract: Numerical simulations were conducted to study the fluid dynamic mechanisms of a scramjet combustor with H₂ as the fuel.An implicit finite volume method was used to solve the 3-D,viscous,turbulent Navier-Stokes equations and chemical species continuity equations.The effects of ramp swept angle on supersonic mixing were analyzed.The results show that swept ramps give better mixing results and stronger stream vorticity than unswept ramp and that mixing is strengthened with the increase of swept angle,but a total pressure recovery coefficient drop is accompanied.