A turbofan engine is another variant built on top of a turbojet engine that uses a turbine to generate shaft power and drive a propeller. They are a mixture of the early reciprocating engine drive and the new gas turbine drive. A turbo-prop engine can also be thought of as a turbo-shaft engine, in which the propeller is connected to the shaft via a reduction gear.
A turbofan engine is an evolved version of a turbojet engine that uses the power of its shaft to drive a fan, draw in a large amount of air, compress it, and direct it through an exhaust port to generate thrust. Part of the inlet is used to power the jet engine in the core, the other part is routed through a series of compressors and goes straight through the nozzle without combustion. Thanks to this ingenious mechanism, turbofan engines are quieter and have more thrust.
Components of Turbofan Engine
1) FAN or AIR INLET
The fan is the main part of the turbofan engine. It is also known as the AIR INLET because air introduces into the engine through this part. A large rotating fan draws in a lot of air. The Titanium is used for the construction of the fan blades.
After air suction process, the fan accelerates the air and divide it into two sections. One section of this air is passed by the engine core where it acts on other components of the turbofan engine. The other section of the air passes is known as the “bypass” around the core. It goes through the duct of the engine via a pipe around the core where it creates most of the force that moves the aircraft forward. This cool air helps calm the engine and increases the engine thrust.
The compressor is the first core component of the turbofan engine. The compressor consists has a fan with many blades connected to the shaft. It’s a different level. Each stage consists of a rotating blade and a fixed stator. As the air moves deeper through the compressor, its heat and pressure increase. The energy comes from the turbine and is transmitted along the shaft. Compressed air is then pushed into the combustion chamber.
3) Burner or Combustion Chamber
In the burner, air mixes with fuel before it ignites. There are up to 20 nozzles that inject fuel into the air stream. A mixture of air and fuel ignites. This provides a high temperature, high energy air flow. Fuel burns with oxygen in compressed air.
The interior of the burner is usually made of ceramic material to provide a refractory chamber.
A turbine is made up of a series of blade disks that act like a windmill, extracting energy from the hot gas given off by the combustion chamber. A high-energy flow of air from the combustion chamber enters the turbine and rotates the turbine blades. The turbines are connected by a shaft that rotates the compressor blades and the front intake fan. This rotation takes some energy from the high energy flow that is used to drive the fans and compressors. In some turbine engines (i.e., turboprops, turbo shafts, or turbofan engine), energy is drawn through additional turbine disks and used to power propellers, bypass fans, or helicopter rotors.
The nozzle is the exhaust pipe of a turbofan engine. This is a major component of the turbofan engine that actually creates the aircraft’s thrust. The hot gas rises from the engine exhaust gas through the nozzle to atmospheric pressure. The purpose is to create a fast beam. In most cases the nozzles are convergent and have a fixed flow area. In addition to the cooler air that bypasses the engine core, the low-energy air flow through the turbine generates power when it emerges from the nozzle, which is used to propel the engine and thus the aircraft. The combination of hot air and cold air is expelled to create an exhaust gas that creates forward thrust.