NUMERICAL ANALYSIS OF HYPERSONIC FLOW COUPLED WITH RADIATION AROUND BLUNT-NOSED MODELS

Abstract

In the present work, numerical simulations are carried out in a non-continuum hypersonic regime to analyze the flow properties in the shock layer of a blunt body. Radiative transfer equation is added to the existing Navier-Stokes based solver. The solver is developed within OpenFOAM framework and accommodates features to model air chemistry, multispecies transport, thermodynamic properties of high-temperature air, and non-equilibrium boundary conditions. Simulations involving chemical reactions for high-temperature gases are carried out for Earth and Martian atmosphere. At such temperatures gases tend to dissociate and ionize. Hence, causing lowering of temperature because of endothermic reactions and due to this it also becomes important to solve the species continuity equation along with Navier-Stokes. The radiative transport equation is solved using spherical harmonics (P1) and finite volume discrete ordinate method (fvDOM) approximations. The aerothermodynamics of high-temperature non-equilibrium flow-field over blunt-nosed models for non-reacting gases have been analyzed using our solver and results are validated with DSMC data. Good agreement has been observed with DSMC data and significant improvement is seen when compared to the conventional high-speed compressible flow solver. The results have shown that a considerable amount of heat escapes from the shock-layer region, hence resulting in radiative cooling. It is observed that, if no radiative heat transfer is considered in the solver, it overpredicts the temperature and shock-layer thickness. Therefore incorporation of radiation along with all the non-equilibrium effects in the rarefied hypersonic regime is imperative.