Abstract: An approximate analytic solution for the ablation process heated with constant heat flux is presented. Ablation problems are mathematically analogous to moving boundary problems, which there is a boundary called melting front or moving interface. This moving interface is time dependent and on it thermodynamic equilibrium conditions and dynamic compatibility conditions are to be satisfied. Owing to these reasons, problems are highly nonlinear. The ablation process is divided into two stages, I.e., initially body is heated up to melt-ing temperature and then ablation process is to be started. By means of heat transfer model and the conditions satisfied on the moving interface, the governing equation for the ablated sur-face motion is established. The equation is one-order nonlin-ear differential one and can be solved by algorithm schemes accurately. By use of this equation, the schedule of the ablation process can be determined easily. Simulations for different conditions of surface heat flux are demonstrated.

Key words: Ablation process, Constant heat flux, Moving interface