Influence of ambient pressure on thermal response of polymer matrix composites

Ambient pressure is crucial to the thermal performance of polymer matrix composites, which are usually used as the thermal protection system (TPS) materials of hypersonic vehicles. Aiming at studying the influence of ambient pressure on thermal response of polymer matrix composites, a novel pyrolysis layer model with pressure is presented, and its mathematical model is deduced and programmed in MATLAB. Comparison between numerical results and experimental results of theoretical ablative composite for open testing is given to verify the accuracy of the presented model. After that, thermal responses of phenolic impregnated carbon ablator under ambient pressures range from 1 to 500 kPa are simulated. It is found that accumulation and backstreaming of generated pyrolysis gasses begin to appear with the increase of ambient pressure. And there is an obvious linear correlation between the reciprocal of the material internal pressure and the ambient pressure. In addition, bondline temperature of polymer matrix composites declines as the ambient pressure decreases. Effect of ambient pressure on thermal response of polymer matrix composites cannot be neglected, which should be taken into account in the TPS design. This study contributes to the accurate prediction of thermal response of polymer matrix composites.