Two-Dimensional Ablation in Cylindrical Geometry

Ablation modeling in cylindrical geometry is a very important problem in the thermal modeling of spacecraft, which has not been dealt with adequately in the literature. In the present work, two-dimensional ablation in cylindrical geometry is considered when the incident heat flux varies axially as well as temporally. A novel idea of using an effective inverse Stefan number, which is analogous to the effective heat of ablation (used in the literature), is proposed to be used as a variable nondimensional latent heat of ablation for ablation modeling, indirectly accounting for various processes involved in ablation. A two-dimensional ablation problem is solved by an alternating direction implicit and adjustable time-step scheme, coupled with boundary immobilization. Quasi-one-dimensional and two-dimensional modeling methods have been compared for two different materials, and the effects of variation of the proposed inverse Stefan number with the incident heat flux and the presence of highly conducting structure bonded to the ablative material have been studied. An optimum modeling method under specific conditions is suggested.