Turbofan engines are are used extensively in modern and military aircraft because such engines are less noisy and more economical, they consume less fuel to produce the same amount of useful power than comparable turbojet engines.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

For example the A380 is available with two types of turbofan engines, the Rolls-Royce Trent (photo) and the Engine Alliance GP7000.

 

 

How it works :

 

The air flow comes into the engine, and is sucked and compressed by the fan. Most of the air is directly ejected (Blue arrow) to produce 80% of the engine push for a civil airplane. See how the turbojet engine works by                                          (compressors, combustion camber, turbines).

In fact, to simplify, the turbofan is only a turbojet engine to which we add a supplementary big compressor, the fan.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The principal driveshaft is divided into three parts, to obtain three different speeds.

 

The cone at the rear of the turbofan is not a useless device : it breaks and slows down the supersonic flow line, and avoids turbulence, and in the process, noise and other problems too. Another point: the hot flow is surrounded by the cold flow. Two flows with different temperatures still not mixed, but it reduces the turbulence strongly, and so, the noise…