Direct Coupling of the NEQAIR Radiation and DPLR CFD Codes

Abstract

The NEQAIR line-by-line radiation code is incorporated into the DPLR flow solver such that NEQAIR is now a callable subroutine of DPLR. The radiant energy source term computed by NEQAIR acts as an energy sink, reducing the convective and radiative heating rates, and brings the shock wave closer to the body. The effects of fluid dynamics/radiation coupling are examined by comparing coupled and uncoupled DPLR-NEQAIR results against FIRE II flight measurements and previous computations. Radiation coupling had the greatest effect at the 1643 s FIRE II trajectory point where the stagnation point total heating rate was reduced by 15.1 %. The coupled 1643 s results were closely correlated to the flight measurements. The change in stagnation point total heating rate was 6% at the 1636 and 1645 s trajectory points, and radiation coupling effects were essentially nonexistent at the 1651 s trajectory point. The coupled DPLR-NEQAIR surface heating rate profiles converged after only two updates of the radiant energy source term.