Increasing the bypass ratio of turbofan engine ______ thrust2 pointsDoesn’t affectDecreasesIncreasesIncreases then decreases

To analyze the effect of increasing the bypass ratio of a turbofan engine on thrust, let's consider the function of a turbofan engine and the impact of bypass ratio on performance.

1. Bypass Ratio Definition: The bypass ratio (BPR) is defined as the ratio of the mass of air bypassing the engine core (fan) to the mass of air passing through the engine core (combustor). A higher bypass ratio signifies a larger volume of air moved by the fan relative to the amount of air that goes through the core.

2. Thrust Generation: Thrust in a turbofan engine is produced by two main components: the jet produced by the core and the mass flow of air moved by the fan. When the bypass ratio increases, the engine becomes more efficient in producing thrust primarily because the fan generates more thrust at lower speeds compared to the core jet.

3. Performance Characteristics: Typically, in high-bypass turbofans (like those used in commercial aviation), increasing the bypass ratio leads to higher propulsion efficiency. It allows engines to produce more thrust for the same amount of fuel, improving overall performance in cruise conditions.

4. Conclusion on Thrust Effects: Therefore, increasing the bypass ratio of a turbofan engine generally increases thrust due to the higher mass flow rate of air at the fan stage overpowering the effects of the core's jet thrust reduction.

Final Answer

Increasing the bypass ratio of a turbofan engine increases thrust.