bypass ratio

For correct and wide application of reduced thrust takeoff technique, the temperature characteristics of high bypass ratio turbofan engines and the takeoff performance of large aircrafts were analyzed.

为正确使用和推广减推力起飞技术，分析了高涵道比涡轮风扇发动机温度特性和大型民航机起飞性能。

The results show that a turbofan engine with a small bypass ratio must be installed, and a suitable turbine entry temperature is obtained by optimization with life cycle cost.

结果表明宜采用小涵道比涡扇发动机，而且不考虑费用时涡轮前温度取值越高越好，考虑费用时则有最大值；

However, the approaches in developing high bypass ratio engine and low bypass ratio engine are different.

但是, 在核心机基础上研制大涵道比涡扇发动机和小涵道比加力涡扇发动机的技术途径是不同的.

Therefrom some conclusions are obtained as: 1.The system's bypass ratio must be actively controlled by adjusting both core and bypass engine's through flow areas.

得到：（1）其必为变涵道比循环系统，由可变几何内、外涵通道提供对涵道比的主动控制；

Therefore, the low tip tangential speed design of high bypass ratio is a trend.

因此低叶尖切线速度是将来大涵道比风扇的发展趋势。

Key Technology of Modern High Bypass Ratio Turbofan Engine

现代高涵道比涡扇发动机关键技术