Abstract: With regard to the method for the evaluation of connected-pipe ramjet performance, present evaluation index such as combustion efficiency and total pressure loss is introduced, and the connection between connected-pipe experiment and free-jet experiment is analyzed, and the limit of the present evaluation index is illustrated. In order to evaluate the comprehensive effect of combustion efficiency and total pressure loss towards the performance of connected-pipe ramjet combustor and give a reference to the design of ramjet to be tested in free-jet experiment, according to the characteristics of connected-pipe experiment, a new evaluation index named revised impulse ratio based on thrust performance is introduced. The combustion efficiency, total pressure loss and revised impulse ratio is calculated. The results show that the value of revised impulse ratio based on three different methods shows the same variation trend. There exists a good match among the value of revised impulse ratio , combustion efficiency and total pressure loss.

Key words: Combustion efficiency; Total pressure loss; Evaluation index; Modified momentum ratio

摘要： 针对亚燃冲压发动机直连式试验中燃烧室性能评价的问题,对原有的燃烧效率及总压损失等评价指标进行了介绍,同时对自由射流试验与直连式试验之间的联系与区别进行了分析,并阐述了现有评价指标的局限性。为了综合衡量总温及总压对直连式试验中发动机整体性能的影响,从而为自由射流试验中燃烧室结构的设计提供参考,依据直连式试验的特点,建立了基于推力性能的新型评价指标——修正动量比。针对一组亚燃冲压发动机直连式试验数据,计算了其燃烧效率、总压损失及修正动量比。结果显示,三种方法计算出的修正动量比具有相同的变化趋势,修正动量比与燃烧效率及总压损失所反映的燃烧室性能比较吻合。

关键词: 燃烧效率;总压损失;评价指标;修正动量比