The GE90-115B engine is a commercial turbofan jet engine employed on the Boeing 777-300ER commercial aircraft. It is the most powerful commercial jet engine employed today by the civilian aircraft industry. Let us remember that a turbofan engine utilizes a big portion of the turbine work to supply power to the fan, which is located at the entrance of the engine. It also provides extra air to the burner (combustion chamber). It is generally more economic and efficient than a turbojet engine for high subsonic cruise speeds due to its high-bypass-ratio.
The GE90-115B accelerates a larger mass of air to a lower velocity than other engines for a higher propulsive efficiency. Its frontal area is quite large compared to other turbofan engines, and for this reason more drag and more weight is produced. Its large fan blades propel bypass air, which flows along the engine axis between the inner and outer engine casings. Although this air is not burned, it provides addition thrust.
Components
The GE90-115B consists of two rotor shafts; a high-pressure shaft and a low-pressure shaft. Therefore, it has high-pressure compressor and low pressure compressor. Its high-pressure compressor is composed of 9 stages, with each one of them being composed of a stator and a rotor containing blades. It also has a 2-stage high-pressure turbine next to its high-pressure compressor, sharing the same shaft.
The combustion chamber, where fuel is injected and burned, is situated between the high-pressure compressor and the high-pressure turbine. Aside from the 4-stage low-pressure compressor, the low-pressure shaft has also a 6-stage low-pressure turbine at the other end, with the high-pressure compressor and the high-pressure turbine in between. The massive fan, which is located at the entrance, is set up before the 4-stage low-pressure compressor. The gear-box, which set the high-pressure shaft in motion, is located right below the high-pressure compressor.
Below, a simple diagram of a GE90-115B turbofan engine showing its essential parts
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