Name: How Jet Engines Work
Uploaded: 2021-02-23T15:54:25.000Z
Duration: 5 min 1 s
Description: VoiceTubeの動画で発音を聞きながら英語表現を覚えよう！学べる英語：

I'm Jake O'Neal, creator of Animagraffs, and this is

Most jet propelled airplanes use a turbofan design.

The turbofan can be thought of as a high tech propellor inside of a duct called a diffuser,

The core of a jet engine is a gas generator that creates high pressure gas to power a

This setup has compressor, combustor, and turbine sections.

Compressed air makes for a much more powerful combustion reaction relative to engine size.

Compression happens in stages that force incoming air into an increasingly narrow chamber.

A single compressor stage is comprised of a spinning rotor paired with a ring of stationary

stator vanes which are attached to the core casing.

Rotor blades swirl the air as they force it through the compressor.

Stator vanes slow this swirling momentum in exchange for increased air pressure.

This compressor has four low pressure and ten high pressure stages.

Air is mixed with fuel and ignited as it passes through the combustor, releasing a jet of

The design shown here is an annular combustor, meaning "ring shaped."

Each nozzle is coupled with a fuel injector, and is designed to swirl the incoming fuel

A couple of ignitor plugs, not unlike the spark plugs found in car engines, ignite this

mixture and the reaction spreads evenly around the ring.

Once started, combustion continues as long as air and fuel are supplied.

Turbines at the rear of the jet engine are powered by exhaust gasses exiting the combustor.

Much of the turbine power is used to turn the fan while a smaller percentage powers

Some air from the compressor is diverted for cooling, and special coatings are used to

The exhaust cone is specially shaped to mix

It also covers sensitive internal engine parts.

Early jet engines were turbojets, where all incoming air flows through the core.

Most modern winged aircraft engines are turbofans, where only a fraction of air enters the core

or gas generator, and the resulting power turns a specially designed fan.

Again, the fan can be thought of as a high-tech propeller inside of a duct.

Air that does not enter the core is called bypass air.

High bypass engines are designed to move large quantities of air at slower cruising speeds

The exchange for high efficiency is engine size – high bypass engines can be very large,

Commercial airliners or military transport aircraft are example applications.

Exhaust velocity is a major factor in jet engine noise.

High bypass engines surround fast-moving core exhaust with large quantities of slower-moving

Military fighter aircraft use low bypass engines, which are more compact, have high power-to-weight

ratios, plus supersonic and afterburner capabilities, in exchange for things like poor noise control

High performance engines may have afterburner capability.

Additional fuel is sprayed into a jet pipe section where it mixes with exhaust gas, and

is ignited, producing a second stage of combustion.

Since afterburner is fuel inefficient, it's generally used in short bursts during takeoff,

The exhaust nozzle is adjustable for maximum exhaust acceleration and to avoid undesirable

back-pressure which can harm forward engine parts.

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How Jet Engines Work