对旋风扇不同转速匹配对失速关键级影响实验

对低速对旋风扇/压气机级的理论分析表明，对旋转子的失速关键级取决于失速时前后级的流量系数以及前后级固有的临界流量系数.前后级的转速匹配会改变前后级的流量系数，进而改变对旋风扇的失速关键级.在一台低速轴流对旋风扇上进行了不同转速匹配的实验，实验结果验证了这一结论.该实验通过改变前后级转速来研究不同转速比情况下的对旋压气机失速特性.实验中分别测量了前后级在100%，90%，80%，70%，60%，50%转速下，共计36组数据.实验结果表明，在设计转速下第2级转子为失速关键级，并且可以通过调整前后级的转速比来改变失速关键级.另外，在失速时如果前级转子流量系数接近临界值，可以得到明显的失速迟滞回线，否则无法得到迟滞回线. 

Experimental investigation on critical stall stage of counter-rotating fan at different speed ratio

Theoretical analysis on a low-speed counter-rotating fan shows that the critical stall stage is determined by two parameters, one is the critical stall mass flow coefficient of each rotor, the other is the real mass flow coefficient of the two rotors at stall point. An experiment was taken to confirm this supposition. The experiment was carried out on investigating the stall characteristic of a counter-rotating fan at different speed ratio. 36 cases was taken at 100%, 90%, 80%,70%,60%, 50% speed of each rotor. The result shows that the second rotor is the critical stall stage at design speed, and the critical stall stage could be changed by adjusting the speed ratio of the two rotors. It is also observed that the hysteresis stall loop appears when the first rotor is the critical stall stage, while it doesn't appears when the second rotor is the critical stall stage.