Numerical Analysis of Shock Layer in Front of a Super Orbital-Velocity Reentry Capsule.

The calculation code originally developed for a hypersonic nonequilibrium flow is applied to the flowfield in front of a super orbital-velocity reentry capsule. The re-entry speed is assumed to be 12km/sec. The governing equations for a chemically and thermally nonequilibrium flow consist of the full Navier-Stokes equations, including the 11 chemical species mass conservation equations and the vibrational-electronic energy conservation equation. The Park's two-temperature model is used for the chemical reaction rates. A Harten-Yee type upwind TVD scheme is used to solve the governing equations with a fractional step method. A semi-implicit scheme is introduced because of the stiffness of chemical source terms. Under a super orbital-velocity re-entry conditions, the results of numerical calculations indicate that the vibrational excitation behind a strong bow shock is prevented by nitrogen molecule dissociation. The obtained distributions of vibrational and translational temperatures and species mass fractions are essentially sufficient to yield not only the convective but also the radiative heat transfer to the capsule surface using the existing NEQAIR code.