How do jet engines work?

Question

How do jet engines work?

Answer 1

Just like a 4 cycle piston, AK had it right...

Answer 2

They compress jet fuel which ignites and turns a turbine that takes in air for the next ignition cycle and expells air through the rear of the engine.  There for generating forward thrust.. hope this helps! ;-).. BTW.. this is the simple version.. it's a lot more complicated . hope  you get the gyst.

Answer 3

First of all a JET ENGINE is a reaction engine which works according to NEWTON'S LAWS OF MOTION( III LAW). It works according to the Brayton Cycle and it's basic priciple is it discharges a fast flowing fluid through the exhaust(NOZZLE) thereby generating thrust. Jet engines includes turbojets, turbofans, rockets, ramjets, pulse jets and pump-jets.In detail we can see how it works.

                            In a turbojet engine air is drawn into the rotating compressor via the intake and is compressed, through successive stages, to a higher pressure before entering the combustion chamber. Fuel is mixed with the compressed air and ignited by flame in the eddy of a flame holder. This combustion process significantly raises the temperature and volume of the air. Hot combustion products leaving the combustor expand through a gas turbine, where power is extracted to drive the compressor. This expansion process reduces both the gas temperature and pressure but sufficient fuel is burnt so that both parameters are usually still well above ambient conditions at exit from the turbine. The gas stream is then expanded to ambient pressure via a propelling nozzle, producing a high velocity jet as the exhaust. If the jet velocity exceeds the aircraft flight velocity, there is a net forward thrust upon the airframe.

                    

                             This is the working in short if you want more pls let me know .Hope this helps you.

Answer 4

The thumbs down fairy has hit this thread. Most of the answers are basically right.

One big omission in many of them is that most of the air, in a modern turbofan engine, does not get mixed with fuel. Most of it is compressed and exhausted, bypassing the combustion chamber. This allows the engine to get more thrust by ejecting much more air.

Answer 5

Intake - compression - Fuel Mixing - Ignition - Exhaust (under high pressure)

1) Air is drawn in from the intake by rotating the engine.

2) Air is compressed through several stages

3) Fuel mixture is dosed and injected

4) Ignition takes place

5) Air is blown out under great pressure from exhaust.

PS: Once the engine is at sustainable RPM, the rotation of the engine by external means is stopped and the engine then runs on its own.

Answer 6

1. air is sucked in.

2. the air is compressed.

3. compressed air is mixed with fuel.

4. the fuel ignited.

5. the combustion provides thrust out the back of the engine.

Answer 7

***ESSENTIALS***

they suck in air through the front. some is directed around the engine (bypassed)

the rest is then compressed by a series of fan blades.

the compressed air goes in the combustion chamber, where it is mixed with fuel or equivalent and then ignited , the hot air exits through the back at high speeds thus propelling the engine forward.

the exiting air also turns a set of fan blades that is connected with the fans at the front. since the engine is itself a generator  (of electricity, among other things)  this effectively makes the engine self sustainable after startup.  

***EXTRA INFO***

two big types of jet engines are the turbo jet and the turbo fan

the turbojet is developed before the turbofan. it consumes generally more fuel and is louder and less efficient. it is low bypass. meaning nearly all of the air sucked in is compressed and mixed with fuel and ignited.

the turbofan comes second. It is high bypass meaning 40% or more of the air sucked in is directed around the engine with only some of the air compressed, mixed and ignited. the result is that it is more efficient, quieter and generally larger than the turbojet

one kind does not necessarily have higher thrust than the other. thrust is dependent on fuel used and engine size as well as engine technology employed

turbojet and turbofan engines can both be afterburning. or, reheatable. afterburner is the result of extra fuel being dumped into the hot exhaust thus creating a larger detonation directed rearwards and results in a very significant thrust increase

another type is the turboprop. it is not a jet engine but uses the same principle. It is essentially a even higher bypass engine with a large propeller in front instead of a large fan. the compressing mixing and igniting is still the same. it is also self sustainable. because of the propeller, this kind of engine is more effective at lower altitude and medium speeds: no higher than 28,000 feet and no faster than i would say 300 knots)

Answer 8

All jet engines are reaction engines that generate thrust by emitting a jet of fluid rearwards at relatively high speed. The forces on the inside of the engine needed to create this jet give a strong thrust on the engine which pushes the craft forwards.

Jet engines make their jet from propellant from tankage that is attached to the engine (as in a 'rocket') or from sucking in external fluid (very typically air) and expelling it at higher speed; or more commonly, a combination of the two sources.

Answer 9

Fan - The fan is the first component in a turbofan. The large spinning fan sucks in large quantities of air. Most blades of the fan are made of titanium. It then speeds this air up and splits it into two parts. One part continues through the "core" or center of the engine, where it is acted upon by the other engine components.

The second part "bypasses" the core of the engine. It goes through a duct that surrounds the core to the back of the engine where it produces much of the force that propels the airplane forward. This cooler air helps to quiet the engine as well as adding thrust to the engine.

Compressor - The compressor is the first component in the engine core. The compressor is made up of fans with many blades and attached to a shaft. The compressor squeezes the air that enters it into progressively smaller areas, resulting in an increase in the air pressure. This results in an increase in the energy potential of the air. The squashed air is forced into the combustion chamber.

Combustor - In the combustor the air is mixed with fuel and then ignited. There are as many as 20 nozzles to spray fuel into the airstream. The mixture of air and fuel catches fire. This provides a high temperature, high-energy airflow. The fuel burns with the oxygen in the compressed air, producing hot expanding gases. The inside of the combustor is often made of ceramic materials to provide a heat-resistant chamber. The heat can reach 2700°.

Turbine - The high-energy airflow coming out of the combustor goes into the turbine, causing the turbine blades to rotate. The turbines are linked by a shaft to turn the blades in the compressor and to spin the intake fan at the front. This rotation takes some energy from the high-energy flow that is used to drive the fan and the compressor. The gases produced in the combustion chamber move through the turbine and spin its blades. The turbines of the jet spin around thousands of times. They are fixed on shafts which have several sets of ball-bearing in between them.

Nozzle - The nozzle is the exhaust duct of the engine. This is the engine part which actually produces the thrust for the plane. The energy depleted airflow that passed the turbine, in addition to the colder air that bypassed the engine core, produces a force when exiting the nozzle that acts to propel the engine, and therefore the airplane, forward. The combination of the hot air and cold air are expelled and produce an exhaust, which causes a forward thrust. The nozzle may be preceded by a mixer, which combines the high temperature air coming from the engine core with the lower temperature air that was bypassed in the fan. The mixer helps

Answer 10

Same answer as above. A Turbo-prop does the same thing but the turbine at the exhaust powers a propeller instead of fan blades. This actually makes a turbo-prop more complicated but more efficient at lower altitudes than a jet.

Answer 11

Here is an easy  theory to remember!!

Inhale,Compress,Bang, and Exhale

air comes in the front of the engine, it compresses it,then there is the introduction to fuel and that causes an explosion, and then  blows the air out the back of the engine, generating thrust to push the aircraft forward!

Answer 12

Then intake air and almost like a blowing on a lighter, the fuel is injected. Also the turbines in the front of the engine pylon is used to take in air in a more powerfull and straight forward way than a propeller.

Answer 13

More complete answers, with drawings/pictures/diagrams, can be found if you Google 'jet engines' or Google 'How Things Work' and then go to the right category at that site.

Answer 14

Suck, squeeze, bang, blow.