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分析了烧蚀发动机和高过载烧蚀发动机实验得到EPDM(三元乙丙)的炭化层结构,获得烧蚀过程炭化层结构形成变化的机理,建立了考虑疏松致密结构的多孔炭化层物理模型.模型中炭化层为非均质的多孔可渗透介质,孔隙内部存在气体扩散和热化学反应;炭化层中热解气体沉积效应形成致密结构.在多孔介质流动与传热算法基础上建立了模拟绝热材料烧蚀过程的数值方法,计算得到的炭化率、质量烧蚀率和炭化层的多孔结构与实验结果相吻合,证明了本烧蚀模型能够准确地描述绝热材料的热化学烧蚀过程,并为耦合烧蚀模型的建立提供数值算法基础.
The structure of the carbonized layer of EPDM (EPDM) was obtained through the experiment of ablation engine and high-overload ablation engine. The formation mechanism of the carbonized layer during ablation was obtained. The physical model of porous carbonized layer considering the dense and loose structure was established. In the model, the carbonized layer is a heterogeneous porous permeable medium, and gas diffusion and thermochemical reactions exist in the pores, and the deposition effect of pyrolysis gas in the carbonized layer forms a dense structure. Based on the porous medium flow and heat transfer algorithm, The numerical method of material ablation process, the calculated carbonization rate, mass ablation rate and the porous structure of carbonized layer coincide with the experimental results, which proves that the ablation model can accurately describe the thermal chemical ablation process of the thermal insulation material The numerical algorithm is provided for the establishment of coupled ablation model.