What is the main advantage of turbofan engines over turbojet engines?

The main advantage of turbofan engines over turbojet engines lies in their ability to produce higher thrust without significantly increasing fuel flow. This is achieved through the design of turbofan engines, which incorporate a larger fan at the front that moves a substantial volume of air, enhancing thrust in a more efficient manner compared to turbojets.

Turbofan engines operate on the principle of bypass ratio, delivering thrust both from the hot exhaust gases (like turbojets) and from the large volume of cooler air that bypasses the engine core. This design leads to greater efficiency, particularly during subsonic speeds, where turbofans excel.

The impact of this high bypass ratio is particularly evident in commercial aviation, where efficiency and thrust are crucial. This results in reduced operational costs, better fuel efficiency, and generally quieter operations compared to turbojets, which exclusively rely on jet thrust from the engine's core and do not utilize bypass air.