Numerical simulation for aerodynamic heating and opposing jet thermal protection

Abstract

Based on the theory and semi-em pirical form ulas, the surface heating flux of warhead at zero attack angle under aerodynamic heating is calculated by using reference enthalpy method, and the equilibrium curves of temperature for radiation of wall are obtained, by which the anti-thermal effects of blunt leading edge is proved in this paper. At the same time, the anti-thermal effects of thermal protection system with opposing jet are simulated by using methods of CFD. The heating flux of wall under opposing jet is predicted, and the numerical simulation results are well agreement with the experiment results. stagnation point of the hemispherical nose to emit high pressure gas, so that detached shock wave is away from the hemispherical nose under the impact of jet flow, low temperature jet gas attaches to the surface ofobjects under the impact of coming flow and forms the low-temperature gas back flow region near the spout, thereby the quality of heat transferred to wall is reduced, namely the aerodynamic heating is reduced.II. PREDICTION OF AERODYNAMIC HEATINGwhere pOJ and Ps is gas density of wall and stagnation point respectively, Jim and Jis is gas viscosity coefficient of wall and stagnation point respectively. To non-stagnation region, the interesting domain is limited to the laminar boundary layer in this paper, after taking impact of wall temperature into account, Lees heating flux equation for laminar flow is qwJ p*J/u e r 1 jii; (lP*.u*uer21dxt (2) qOJS 2(j+l)P;.u;C;1 for plane flow j = 0 ; for symmetry flow j = 1 . The method of reference enthalpy is used in (2) and Eckert reference(1) Calculation ofHeating FluxThe parameters of boundary layer edge are calculated by solving three-dimensional unsteady compressible Euler equations directly. Euler equations are discretized by using Finite Volume Method and the computational grids are unstructured. After this we use four-step Runge-Kutta Law to carry out numerical calculating with explicit time integral scheme.The heating flux of stagnation point is calculated by using Fay-Riddell equation [4]. Related dimensionless parameters are assumed to be constants: Pr = 0.71, Le = 1.0 -2.0 , Psf.1s/P m f.1(J) = 0.17 -1.0, then the heating flux equation of stagnation point under the condition of equilibrium boundary layer is qOJs = O.763P r -n·6 (pOJf.JOJ J0.

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Aero-Thermal Response Analysis for Sharp ZrB₂-SiC Leading Edge of Waverider

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