Numerical Simulation of Thermal-Chemical Non-equilibrium and Radiating Hypersonic Flow
When a reentry capsule flies at a high speed through the earth atmosphere, the temperature of the shock layer formed around it may become sufficiently high to emit a significant amount of radiation. The radiation emanates mainly from the inviscid region of the shock layer where the flow is highly dissociated and ionized. When the radiation passes through the cold boundary which is near the wall, the radiation is absorbed by the air, so that the boundary layer is heated, while the inviscid region is cooled.When the magnitude of the radiation involved is significant in comparison with the convective heat flux at the wall, the radiation must be considered in the calculation of the heat load to the vehicle. To solve this problem, a number of computational methods have been developed such as NONEQ, LORAN, RASLE and SPRADIAN. However, most of them can only be applied on the structured grids with simplified radiation models. This paper presents a computational method which can simulate both the thermal-chemical non-equilibrium and air radiation on the same unstructured grids at a high temperature situation in order to solve the hypersonic problem with complicated geometries.
KeywordsShock Layer Hypersonic Flow Atomic Line Thermal Protection System Cold Boundary
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- 1.Park, C., Milos, F.S.: Computational equations for radiating and ablating shock Layers. In: AIAA-90-0356. AIAA, America (1990)Google Scholar
- 2.Hartung, L.C.: Nonequilibrium Radiative Heating prediction method for aeroassist flowfields with coupling to flowfield solvers. Phd Thesis, Raleigh (1991)Google Scholar
- 3.Nicolet, W.E., Waterland, L.R., Kendall, R.M.: Method for predicting radiation-coupled flowfields about planetary entry probes. Aerodynamics Heating and Thermal Protection Systems: AIAA Progress in Astronautics and Aeronautics 59, 120–136 (1978)Google Scholar
- 4.Kazuhisa, F., Takashi, A., Kojiro, S.: Air radiation analysis of a superorbital reentry vehicle. In: AIAA -1997-2561. AIAA, American (1997)Google Scholar
- 6.Park, C.: Problems of rate chemistry in the flight regimes of aeroassisted orbital transfer vehicles. In: Nelson, H.F. (ed.) Progress in Astronautics and Aeronautics: Thermal Design of Aeroassisted Orbital Transfer Vehicles. AIAA, America (1985)Google Scholar
- 7.Gupta, R.P.: A review of reaction rates and thermodynamic and transport properties for 11-species air model for chemical and thermal nonequilbrium caculations to 30000K. NASA-TM-101528, NASA, American (1989)Google Scholar
- 8.Morear, S., Laux, C.O.: A more accurate nonequlibrium air radiation code:NEQAIR second generation. In: AIAA, pp. 1992–2968. AIAA, America (1992)Google Scholar
- 9.Hartung, L.C., Mitcheltree, R., Gnoffo, P.A.: Stagnation point nonequilibrium radiative heating and the influence of energy exchange models. AIAA-19 91-0571, AIAA, America (1991)Google Scholar