Multidimensional Effects on Heatshield Thermal Response for the Orion Crew Module

摘要

Transient simulations are performed to predict in-depth thermal response and surface recession of a thermal protection system for the proposed Orion Crew Module. The finite-volume codes used in this simulation solve the time-dependent governing equations, including energy conservation and a three-component decomposition model, with a surface energy balance condition and a moving grid system to predict shape change due to surface recession. Solutions are obtained for the full three-dimensional geometry and for simplified one-dimensional geometries. The one-dimensional computations are performed at selected locations and are compared with the three-dimensional predictions for a candidate heatshield material. The aerothermal environments are derived from proposed Lunar return trajectories. The results indicate that multidimensional effects have little influence on the predicted surface recession. At the heatshield shoulder, where the maximum heating occurs, a one-dimensional planar model underpredicts the bond-line temperature. An improved one-dimensional model, that takes into account the variation of cross sectional area with depth from the surface, provides a better approximation to the in-depth temperature response predicted by the three-dimensional model.