Abstract: According to the ablation behavior of EPDM insulator in gas environment，a double zones bulk ablation model is established，taking deposition reaction，gas erosion and expansion phenomena into account. The porous medium zone and the solid zone are solved separately and interface temperature coupling numerical method is used. The numerical calculations for ablation experiments in gas phase environment are carried out，the main influence factors of the carbon layer pore structure and the mass ablation rate are analyzed. The computational results agreed well with the experimental ones. The speed magnitude of ablating gas in carbon layer is about millimeter to centimeter pre second，the relative pressure magnitude is about 103 ~ 104Pa，and the relative pressure distribution in carbon layer is also obtained.

Key words: Solid rocket motor；Ablation model；Deposition reaction；Gas erosion；Expansion；Porous structure；Ablating gas

摘要： 针对气相环境下EPDM绝热材料的烧蚀行为建立了双区体烧蚀模型，着重考虑了沉积反应、气流剥蚀和膨胀现象。多孔介质区和固体区分开求解，采用交界面温度耦合的数值处理方法。对气相环境下的烧蚀实验开展了数值计算，分析了影响炭化层孔隙结构、质量烧蚀率的主要因素，计算结果与实验结果吻合较好。计算还获得了炭化层内烧蚀气体流速的量级是毫米到厘米，相对压强的量级是103～104Pa以及相对压强的分布情况。

关键词: 固体火箭发动机；烧蚀模型；沉积反应；气流剥蚀；膨胀；孔隙结构；烧蚀气体