Two-dimensional implicit thermal response and ablation program for charring materials

The TITAN program for predicting charring material ablation and shape chang e of thermal protection materials is presented. The governing equations inc lude energy conservation and a three-component decomposition model. The sur face energy balance condition is solved with a moving grid to calculate the shape change due to surface recession. The governing equations are discret ized with a finite volume approximation with a general body-fitted coordina te system. A time-accurate solution is achieved by an implicit time-marchin g technique with Gauss-Seidel line relaxation with alternating sweeps. Benc hmark solutions are calculated and compared with available solutions to che ck code consistency and accuracy. For fully coupled solid-fluid simulation, this technique has been directly integrated with both a high-fidelity Navi er-Stokes solver and an aerothermal flowfield engineering correlation code. Representative computations, including a slender hypersonic reentry vehicl e and a flat-faced cylinder model in an arcjet test, are presented and disc ussed in detail.