How an Airplane Engine Works || Full theory || Types of Jet Engines

 

✈️ How an Airplane Engine Works (Jet Engine – Turbofan)

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🔧 Basic Principle

Jet engines work on Newton’s Third Law of Motion:

"For every action, there is an equal and opposite reaction."

The engine throws air backward at high speed → this creates a forward thrust → which pushes the airplane forward.

🚀 Types of Jet Engines

1. Turbofan – Used in commercial planes (more efficient, quieter)

2. Turbojet – Used in older fighter planes

3. Turboprop – Jet engine that drives a propeller

4. Ramjet – Used at very high speeds (no moving parts)

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🌀 Jet Engine Main Parts and Working

1. Fan (Air Intake)

• The big front fan pulls in a huge amount of air.

• Some of this air goes into the core (for combustion), and the rest bypasses around the engine (bypass air) for extra thrust.

• This bypass air also helps in noise reduction and fuel efficiency.

2. Compressor

• The compressor squeezes the incoming air to increase its pressure.

• It consists of multiple rotating blades (rotors) and stationary blades (stators).

• Highly compressed air is passed to the next stage: combustion.

3. Combustion Chamber

• Here, fuel (aviation kerosene) is sprayed and mixed with high-pressure air.

• The fuel-air mixture is ignited, creating very high-temperature, high-pressure gas.

• This gas rapidly expands and moves toward the turbine.

4. Turbine

• The hot gases spin the turbine blades.

• The turbine is connected by a shaft to the compressor and fan.

• So, when the turbine spins, it powers the compressor and front fan.

• After passing the turbine, the gases still have high energy and are expelled.

5. Exhaust (Nozzle)

• The remaining hot gases are forced out through the exhaust nozzle at high speed.

• This high-speed jet of air produces thrust that pushes the airplane forward.

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What is Thrust?

Thrust is the forward force that pushes the engine and, therefore, the airplane forward. Sir Isaac Newton discovered that for “every action there is an equal and opposite reaction.” An engine uses this principle.

🔥 Thrust Production

The total thrust =
(Mass of air expelled) × (Velocity of exhaust – Velocity of intake)

More air and faster exhaust = more thrust.

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🌍 Supporting Systems

• Fuel system: Delivers fuel to the combustion chamber.

• Oil system: Lubricates moving parts like turbines.

• Cooling system: Manages extreme heat.

• FADEC (Full Authority Digital Engine Control): Computer system that controls engine performance.

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📌 Summary in Simple Steps:

1. Fan pulls in air.

2. Compressor increases air pressure.

3. Fuel burns in the combustion chamber with high-pressure air.

4. Turbine is spun by hot gases and powers compressor + fan.

5. High-speed exhaust creates thrust.