Thermal Analysis of Honeycomb Sandwich Panels as Substrate of Ablative Heat Shield

摘要

This study describes a method to extend the one-dimensional charring material ablation code developed by Aerotherm Corporation to simulate honeycomb sandwich panels protected by ablative heat shields. Modeling of one-dimensional elements with a variable surface area was embedded in the original charring material ablation code to model nonplanar surfaces. This feature was used in the current study to simulate conductive heat transfer through honeycomb sandwich panels. For internal radiation exchanges, a useful form of steady-state radiation heat flux is derived from an energy balance inside enclosed honeycomb cells. This form makes the system of equations appropriate to be solved by a Gauss-Seidel iterative method. Furthermore, comprehensive formulations are provided to calculate internal radiation view factors between the faces of right prisms with an arbitrary polygon base. The results are presented in two parts. First, the thermal response of metallic sandwich panels as a hot structure is investigated. The thermal behavior of the panel is compared with that of the familiar Swann-Pittman model. Second, the thermal response of stainless-steel panels that are protected by a carbon-phenolic ablative heat shield is determined. In this part, a parametric study is conducted to quantify some important geometrical factors that influence the thermal analysis and performance. The results from both parts provide verification for the simulation tool developed in this study.