超轻质石英/酚醛复合材料烧蚀行为与多物理场数值模拟

Ablation behavior and multi-physical field numerical simulation of ultra-lightweight quartz/phenolic composite

基于超轻质石英/酚醛复合材料的烧蚀防热机制,建立了包含二氧化硅相变的复合材料烧蚀多物理场模型,预测了超轻质石英/酚醛复合材料的表背面温度、热解度、不同层厚度及孔隙压力分布。数值模拟通过计算获得了表面二氧化硅液态层厚度变化规律,模型预测的温度结果与烧蚀实验中测量结果吻合。根据各项传热模式的热流分析结果可见,对防/隔热机制影响最主要的是热辐射、热阻塞和二氧化硅气化。针对超轻质石英/酚醛复合材料的典型服役工况,采用0.5~2.5 MW/m^(2)之间热流密度作为环境输入参数,研究了不同热流密度条件下超轻质石英/酚醛复合材料的烧蚀行为,结果表明:超轻质石英/酚醛复合材料表面烧蚀后退量随热流密度的增加而增加;热流密度小于1.5 MW/m^(2)时表面液态层厚度随热流密度的增加而增加,热流密度大于1.5 MW/m^(2)时表面液态层厚度基本保持不变。该模型为深入研究超轻质石英/酚醛复合材料的烧蚀机制提供一定的指导。

Based on the ablation and heat protection mechanism of ultra-lightweight quartz/phenolic composite,a multi-physics field model for the ablation of composite containing silica phase transition was established.The surface and backside temperature,pyrolysis degree,different layer thicknesses and pore pressure distribution of ultra-lightweight quartz/phenolic composite were predicted.The numerical simulation obtained the variation law of the thickness of the liquid layer of surface silica through calculation,and the temperature results predicted by the model are consistent with the measurement results in the ablation experiment.According to the heat flow analysis results of various heat transfer modes,it can be seen that the most important factors affecting the prevention/insulation mechanism are thermal radiation,thermal blockage and silica gasification.Aiming at the typical application conditions of ultra-lightweight quartz/phenolic composite,the heat flux densities between 0.5 MW/m^(2) and 2.5 MW/m^(2) were used as environmental input parameters to study the ablation behavior of ultra-lightweight quartz/phenolic composite.The results show that the surface ablation retreat of ultra-light quartz/phenolic composite increases with the increase of heat flux density;When the heat flux density is less than 1.5 MW/m^(2),the thickness of the surface liquid layer increases with the increase of heat flux density.When the heat flux density is greater than 1.5 MW/m^(2),the thickness of the surface liquid layer remains unchanged.This model provides certain guidance for in-depth research on the ablation mechanism of ultra-lightweight quartz/phenolic composite.