Jet Engine Essay

494 Words2 Pages
Jet engines move the airplane forward with a great force that is produced by a thrust and causes the plane to fly very fast. A jet engine operates on the application of Sir Isaac Newton's third law of physics which states that for every action there is an equal and opposite reaction and propulsion. Propulsion means to push forward or drive an object forward. A propulsion system is a machine that produces thrust to push an object forward. Thrust generated depends on the mass flow through the engine and the exit velocity of the gas This law is demonstrated in simple terms by releasing an inflated balloon and watching the escaping air propel the balloon in the opposite direction. All jet engines, which are also called gas turbines, work on the same principle. The engine sucks air in at the front with a fan. A compressor raises the pressure of the air. The compressor is made up of fans with many blades and attached to a shaft. The blades compress the air. The compressed air is then sprayed with fuel and an electric spark lights the mixture. The burning gases expand and blast out through the nozzle, at the back of the engine. As the jets of gas shoot backward, the engine and the aircraft are thrust forward. These gases exert equal force in all directions, providing forward thrust as they escape to the rear. Engine thrust may be increased by the addition of an afterburner section in which extra fuel is sprayed into the exhausting gases.In a turboprop engine, the exhaust gases are also used to rotate a propeller attached to the turbine shaft for increased fuel economy at lower altitudes. For typical jet engines overall efficiency ranges from 20 to 40%. A very tiny fraction of a percent goes to generate noise. The vast majority of the energy not used for propulsion is wasted as heat. Jet engine efficiency calculation is very complicated and depends on a lot of

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