What is a high bypass engine?
In a high-bypass design, the ducted fan and nozzle produce most of the thrust. Turbofans are closely related to turboprops in principle because both transfer some of the gas turbine’s gas power, using extra machinery, to a bypass stream leaving less for the hot nozzle to convert to kinetic energy. Turbofan engines are inherently quieter than turbojets for a given level of thrust. A turbofan thrust is developed by turning a fan with a turbine engine that accelerates a larger amount of air to a lower velocity than do turbojets.Assuming the turbofan’s core and the turbojet are the same size, the turbofan pushes more air due to the bypass air. More thrust for the same amount of power means the turbofan does not need to burn as much fuel as the turbojet to create the same amount of thrust. This means that the turbo fan is more fuel efficient.Efficiency: High-Bypass Turbofan engines are renowned for their exceptional fuel efficiency, which is made possible by the high bypass ratio and optimized airflow configuration.Turbofans are more fuel-efficient than turbojets because they use bypass air to generate thrust, reducing the need to burn as much fuel. They are quieter, and offer better performance at subsonic speeds, making them ideal for commercial airliners. However, turbofans are larger and heavier than turbojets.
What is the main advantage of a high-bypass turbofan engine over a turbojet?
Assuming the turbofan’s core and the turbojet are the same size, the turbofan pushes more air due to the bypass air. More thrust for the same amount of power means the turbofan does not need to burn as much fuel as the turbojet to create the same amount of thrust. This means that the turbo fan is more fuel efficient. Turbofans are usually more efficient than turbojets at subsonic speeds, but at high speeds their large frontal area generates more drag. Therefore, in supersonic flight, and in military and other aircraft where other considerations have a higher priority than fuel efficiency, fans tend to be smaller or absent.High-bypass turbofans are typically more efficient than their low-bypass counterparts. They consume less fuel — and they produce fewer emissions — making them a popular choice among commercial airlines. While most commercial jets use high-bypass turbofans, military jets often use low-bypass turbofans.
How does a high bypass jet engine work?
The high bypass ratio refers to the ratio of air that bypasses the core (is energized only by the fan blades) to the air that goes through the core (compressed, mixed with fuel, ignited and shot out the back). Turboprops have bypass ratios of 50–100, although the propulsion airflow is less clearly defined for propellers than for fans. The propeller is coupled to the turbine through a reduction gear that converts the high RPM/low torque output to low RPM/high torque. This can be of two primary designs, free-turbine and fixed.