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为了延长采用真空球排气系统的超声速风洞的工作时间,拟采用二次喉道提高真空球临界工作压强。本文针对Ma=4和Ma=7超声速风洞,采用计算流体软件系统地研究了不同发动机堵塞比对二次喉道起动能力的影响以及不同尺度的二次喉道对真空球临界工作压强的影响。研究结果表明,随着发动机堵塞比的增大,二次喉道的临界起动直径相应增大,呈非线性变化,同时,真空球的临界工作压强下降。因此,二次喉道直径应针对不同的模拟状态和发动机堵塞比范围综合优化选取。
In order to extend the working hours of the supersonic wind tunnel using the vacuum ball exhaust system, it is proposed to use the secondary throat to increase the critical working pressure of the vacuum ball. In this paper, for the Ma = 4 and Ma = 7 supersonic wind tunnel, the influence of different engine blockage ratio on the secondary throat start-up ability and the influence of different throat on the critical pressure of the vacuum ball . The results show that with the increase of engine blockage ratio, the critical starting diameter of secondary throat increases correspondingly and changes nonlinearly. At the same time, the critical pressure of vacuum ball decreases. Therefore, the secondary throat diameter should be optimized for different simulation conditions and engine blockage ratio range.