Abstract: For studying the sealing performance of the gas pressure system used in ramjet fuel tank after long term storage，leakage rate of varied sealing structures was theoretically calculated on the basis of conductance calculating formula，to study its sealing mechanisms and impacts of various negative factors. The loss pressure recurrence formula was deduced from the definition of the leakage rate to evalauate the sealing performance after long stroage. The results，which agree well with the experimental data，show that the pressure will lose no more than 0.15‰ from the initial value after 10 years. It demonstrates that the sealing performace of the current structures satisfy the requirements.

Key words: Ramjet；Fuel tank；Gas pressure system；Long term storage；Sealing performance；Leakage rate

摘要： 为了研究长期贮存对冲压发动机油箱气路系统密封性能的影响，使用流导计算公式推导得到了典型密封结构的漏率计算公式，并通过漏率定义推导得出了长期贮存压差迭代计算公式，对油箱气路系统的典型密封结构在长期贮存条件下的密封能力进行了研究。结果表明，密封结构的漏率主要受内外压差和密封具体形式的影响，现有的密封结构可以保证贮存10年后油箱内气压下降不超过原始压力的0.15‰。计算结果与试验结果的一致性很好，证明了现有油箱气路系统密封方案的合理性。

关键词: 冲压发动机；油箱；气路系统；长期贮存；密封性能；漏率