碳/酚醛防热复合材料烧蚀行为的数值模拟

Numerical simulation of ablation behavior of carbon/phenolic thermal protection system composite

碳/酚醛复合材料被广泛地应用于钝头体表面,是飞行器优秀的热防护材料。为了准确地预测其烧蚀性能,本文从复合材料的组成物纤维和基体的角度出发,基于能量、质量守恒和热分解方程,考虑了烧蚀过程中材料热属性的非线性变化和烧蚀面的退缩,分别计算了纤维和基体的烧蚀性能,预测了烧蚀过程中防热复合材料的温度分布、密度变化、质量损失规律及热属性和线烧蚀率等。结果表明:碳/酚醛复合材料的烧蚀是各种因素相互作用、相互影响的高度非线性过程;烧蚀过程中材料结构具有不均匀的温度分布,烧蚀面区域材料密度衰减最大并且材料的质量损失和损失率几乎呈线性增加;纤维和基体的烧蚀行为存在明显差异,分别预测两者的烧蚀性能,可以为热防护材料的设计提供更加准确的参考和依据。

Carbon/phenolic composite had been widely used as thermal protection system（TPS）.Thus,in order to predict the ablation behavior of the carbon/phenolic composite,a mathematical model was proposed in this paper,which was based on the energy-and mass-conservation principles as well as on the thermal decomposition equation.The ablation process was simulated from the perspective of the fiber and matrix components.The thermal properties during ablation were calculated,and a moving boundary was implemented to consider the recession of the ablation surface.The temperature distribution,density,thermal properties,linear ablation rate and mass loss of the carbon/phenolic composite were predicted.The results show that the ablation of the carbon/phenolic composite is a highly nonlinear process of interaction of various factors.During ablation,the composite material has an uneven temperature distribution and the attenuation of the density on the ablative surface is the largest.In addition,the mass loss and mass loss rate almost increase linearly.The ablation behavior of the fiber and matrix is obviously different.Therefore,in order to provide more accurate reference and basis for the design of thermal protection materials,it is necessary to predict their ablation behavior respectively.