One way to increase the efficiency of a high-bypass jet engine is to turn the fan into an open rotor, a bit like returning to propellers, but using two rings of stubby counter-rotating blades.

提高高旁通飞机引擎的方法之一就是把风扇变成开放式旋翼，有点回归于螺旋桨的味道，但要使用两圈粗短的反旋桨叶。

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The measurements show that the airfoil blade fan prevails over the plate one in the aspects of total pressure efficiency, stable operation range and high efficient operation range.

试验结果表明机翼型叶片在全压效率、稳定运行范围及高效运行范围比相应的板型叶片具有优越性；

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This paper introduces the advantages and real applications of BDK disrotatory high-efficiency axial fan.

介绍了BDK对旋高效轴流式风机的优点及其实际应用情况。

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One way to increase the efficiency of a high-bypass jet engine is to turn the fan into an open rotor, a bit like returning to propellers, but using two rings of stubby counter-rotating blades.

ECONOMIST: A new way to build a greener jet engine