Abstract: In order to evaluate the performance of silicon insulator in the second combustion chamber in ramjet,the ablation mechanics of silicon insulator was analyzed. A model considered fluid field of ramjet combustion has been established. The insulator ablation is due to air blowing, particle impingement and chemical reaction. The results of numerical simulation show that air blowing is the main factor causing insulator ablation. According to experimental data, the simulation results are acceptable. Part of insulator, downstream the inlet and on the two sides of the inlet are seriously ablated. To reduce insulator ablation in ramjet, it is needed to reduce the gas stream blowing-off impact.

Key words: Ramjet; Insulator; Ablation；Numerical simulation

摘要： 为了评估固冲发动机硅基绝热层的烧蚀性能,对硅基绝热层的烧蚀形成机制进行了分析并建立了数值模型。硅基绝热层烧蚀由气动冲蚀,化学烧蚀,颗粒剥蚀三个部分构成。数值结果表明,硅基绝热层失效的主要原因是气动冲蚀,化学烧蚀与颗粒剥蚀影响较小。理论计算同试验获得的烧蚀形态基本吻合,冲压发动机严重烧蚀部位在进气道两侧的下游区域。从结构设计上看,冲压发动机防隔热设计的重点应是降低冲压发动机气流冲蚀影响。

关键词: 冲压发动机; 绝热层; 烧蚀;数值仿真