WEBVTT - How does a jet engine's afterburner work?

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<v Speaker 1>Welcome to Brainstuff from house stuff Works dot com where

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<v Speaker 1>smart happens. Hi Am Marshall Brain with today's question, how

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<v Speaker 1>does an afterburner work on a jet engine? A jet engine,

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<v Speaker 1>like a rocket engine, is a reaction engine. It works

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<v Speaker 1>by throwing mass in one direction and taking advantage of

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<v Speaker 1>the reaction in the opposite direction. In the case of

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<v Speaker 1>a jet engine, the engine bird's fuel like kerosene with

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<v Speaker 1>error from the atmosphere. The burning fuel heats and expands

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<v Speaker 1>the air, and this hot air shoots out the exhaust

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<v Speaker 1>end of the engine to create thrust. Most modern jet

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<v Speaker 1>engines use a turbine to improve the efficiency of the

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<v Speaker 1>engine and allow the engine to work at low speeds.

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<v Speaker 1>One part of the turbine sucks in airror and compresses

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<v Speaker 1>it before the fuel is injected. The back portion of

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<v Speaker 1>the turbine acts like a windmill, extracting entered from the

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<v Speaker 1>exhaust gases and using the energy to spin the compressor portion.

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<v Speaker 1>A modern turbine engine is extremely efficient and there's still

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<v Speaker 1>a lot of oxygen available in the exhaust stream. The

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<v Speaker 1>idea behind an afterburner is to inject fuel directly into

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<v Speaker 1>that exhaust stream and burn it using the remaining oxygen.

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<v Speaker 1>This heats and expands the exhaust gases further, and it

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<v Speaker 1>can increase the thrust of a jet engine by fifty

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<v Speaker 1>or more. The big advantage of an afterburner is that

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<v Speaker 1>you can significantly increase the thrust of the engine without

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<v Speaker 1>adding much weight or complexity to the engine. And afterburner

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<v Speaker 1>is nothing but a set of fuel injectors, a tube

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<v Speaker 1>and flame holder that the fuel burns in, and an

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<v Speaker 1>adjustable nozzle. A jet engine with an afterburner needs that

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<v Speaker 1>adjustable nozzle so that it can work with and without

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<v Speaker 1>the afterburners on the disadvantage of an afterburner is that

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<v Speaker 1>it uses a ton of fuel for the power it generates. Therefore,

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<v Speaker 1>most planes use afterburners sparingly. For example, a military jet

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<v Speaker 1>would use its afterburners when taking off from a short

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<v Speaker 1>runway on an aircraft carrier or during a high speed

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<v Speaker 1>maneuver in a dog fight. Do you have any ideas

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<v Speaker 1>or suggestions for this podcast? If so, please send me

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<v Speaker 1>an email at podcast at how stuff works dot com.

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