Analysis of influence of fabric architecture and radiation characteristics on effective thermal conductivity of carbonized woven thermal protection composites

Abstract

Resin-based 2.5D angle interlock woven composites are selected as the thermal protection materials used in thermal protection system (TPS) of hypersonic spacecrafts in entry missions in recent years. The accurate prediction of the effective thermal conductivity of these materials in their carbonization state is critical for evaluating their thermal protection performance. Taking both the thermal conduction and the thermal radiation in carbonized 2.5D angle interlock woven composites into consideration, a multi-scale analysis for obtaining the effective thermal conductivity of carbonized ablative woven composite is developed in this study. The multi-scale method is validated by implementing it to predict the effective thermal conductivity of a carbonized plain-woven silica/phenolic composite. Furthermore, the influence of the meso-structure characteristics of fabric architecture (differences in mesoscopic and macroscopic geometric characteristics caused by weave parameters) and the spectral characteristics (extinction coefficients) on the equivalent properties of carbonized woven composites is analyzed. The main results show that thermal radiation plays an important role in determine the effective thermal conductivity of carbonized woven composites, the weave parameters of yarns significantly affect the heat transfer path in these materials, and the equivalent properties considering both thermal conduction and thermal radiation are related to radiation characteristics and fabric architecture. This study can help for the design of thermal protection materials in current TPS.