变截面超-超引射器启动特性数值研究

为研究不同结构参数与来流参数下变截面超-超引射器的启动特性，用于指导超-超引射器设计与工况调试，采用二维雷诺平均Naiver-Stokes方程，数值研究了引射器混合室不同收缩比、一次流和二次流的不同总压比、总温比下超-超引射器的启动规律，并定义了“启动系数”来判别超-超引射流场是否建立。研究结果表明:随着收缩比（范围0.7～0.9）的增加，超-超引射器启动的临界总压比、总温比均先降低后升高，收缩比0.8时，存在最佳总压比5.88，最佳总温比0.21。结构参数一定，超-超引射器随总温比升高启动难度增加。当超-超引射器处于启动状态下，室压不随总温比、总压比变化而变化，引入的启动系数较引射系数可不依赖具体工况而直接判别超-超引射器是否启动。

Starting characteristics of variable section supersonic-supersonic ejector

To study the starting characteristics of the variable cross-section supersonic-supersonic ejector with different structural and flow parameters, the two-dimensional Reynolds averaged Naiver-Stokes equations were employed to examine the different total pressure and total temperature ratios of primary and secondary flows in the mixing chamber of the ejector. The “start-up coefficient” was defined to test whether the supersonic-supersonic field was established. The results show that the critical total pressure ratio and total temperature ratio of ejector start-up first decreased and then increase with the increase of the contraction ratio (range 0.7?0.9). When the contraction ratio is 0.8, the optimal total pressure ratio is 5.88 and optimal total temperature ratio is 0.21. With fixed structural parameters, it is more difficult to start the supersonic-supersonic ejector when the total temperature ratio is higher. In the starting state of the supersonic-supersonic ejector, the chamber pressure is constant as the total temperature ratio and total pressure ratio vary. Also, compared with the ejector coefficient, the defined start-up coefficient can directly determine whether the supersonic-supersonic ejector has started or not, regardless of the specific working conditions.