JET ENGINE Senator. Libya

8/9/2019 JET ENGINE Senator. Libya

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Represented byRepresented by \\

Eng. ALI FADIEL ALIEng. ALI FADIEL ALI


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ContentsContents

Jet engineJet engine

ComponentsComponents

How does a jet engine workHow does a jet engine work

TypeType

DescriptionDescription

AdvantagesAdvantages DisadvantagesDisadvantages


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Jet engineJet engine

AAjet enginejet engine is an engine that acceleratesis an engine that acceleratesand discharges a fast moving jet ofand discharges a fast moving jet offluidfluid totogenerate thrust in accordance withgenerate thrust in accordance with NewtonNewton's'sthird law of motionthird law of motion. This broad definition of. This broad definition of

jet engines includesjet engines includes turbojetsturbojets,, turbofansturbofans,,rocketsrockets andand ramjetsramjets andand water jetswater jets, but in, but incommon usage, the term generally refers tocommon usage, the term generally refers toaa gas turbinegas turbine used to produce a jet of highused to produce a jet of highspeed

exhaust gases for special propulsivespeed exhaust gases for special propulsivepurposes.purposes.


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ComponentsComponents

The basic components (parts) of a jet (airThe basic components (parts) of a jet (air--breathing) engine are the : inlet,breathing) engine are the : inlet,compressor or fan, combustor (burner), acompressor or fan, combustor (burner), aturbine (engine) and an exit nozzle. Someturbine (engine) and an exit nozzle. Someengines may not have all these parts. Theengines may not have all these parts. The

figure below shows a jet engine with thesefigure below shows a jet engine with thesecomponentscomponents


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InletInlet::

The inlet is where the air goes into theThe inlet is where the air goes into theengine. The inlet slows the air flow intoengine. The inlet slows the air flow intothe compressor. The compressor worksthe compressor. The compressor worksbetter when the air flow coming in is slow.better when the air flow coming in is slow.The inlet is made differently if the airplaneThe inlet is made differently if the airplaneis going to fly faster than the speed ofis going to fly faster than the speed ofsoundsound


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Compressor:Compressor:

The compressor takes air in and squeezesThe compressor takes air in and squeezesit. The same thing happens to the air youit. The same thing happens to the air youblow into a balloon. When the air underblow into a balloon. When the air under

pressure goes out of the balloon it causespressure goes out of the balloon it causesthrust (push). When the air leaves thethrust (push). When the air leaves thecompressor it is mixed with fuel (gas) andcompressor it is mixed with fuel (gas) and

burned. The gases move at high speed,burned. The gases move at high speed,just like coming out of a balloon.just like coming out of a balloon.


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CombustorCombustor::

As the air comes into the combustor it is mixedAs the air comes into the combustor it is mixed

with fuel and burned. The right amount of airwith fuel and burned. The right amount of airand gas must be mixed and burned to get theand gas must be mixed and burned to get themost thrust. The gases become very, very hot.most thrust. The gases become very, very hot.The engineer must make sure the combustor isThe engineer must make sure the combustor is

made of metals that will not bend or break whenmade of metals that will not bend or break whenthere is high heat. The hot gases that come outthere is high heat. The hot gases that come outgo to the turbine to increase thrust and to rungo to the turbine to increase thrust and to runthe compressorthe compressor ..


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Turbine:Turbine:

A turbine is also called an engine. This engine orA turbine is also called an engine. This engine orturbine runs the compressor. The hot gasesturbine runs the compressor. The hot gases

move very fast out of the combustor throughmove very fast out of the combustor throughthe turbine and out into the air as thrust.the turbine and out into the air as thrust.

Sometimes an "afterburner" is added after theSometimes an "afterburner" is added after theturbine. The afterburner heats up the gasesturbine. The afterburner heats up the gases

again to get more thrust. The amount of heat isagain to get more thrust. The amount of heat isimportant. Too much heat can bend or breakimportant. Too much heat can bend or breakparts in the turbine.parts in the turbine.


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Nozzle:Nozzle:All the heated gases finally come out theAll the heated gases finally come out the

back end of the jet engine through aback end of the jet engine through anozzle. The nozzle is designed a specialnozzle. The nozzle is designed a specialway to help the hot gases move evenway to help the hot gases move evenfaster. This creates more thrust. Thefaster. This creates more thrust. Thenozzle must be made of the kind of metalsnozzle must be made of the kind of metalsthat won't melt or bend under high heat.that won't melt or bend under high heat.


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How does a jet engine workHow does a jet engine work

jet engine uses a gas turbine to drive ajet engine uses a gas turbine to drive afan that sucks in air, mixes it with burningfan that sucks in air, mixes it with burning

fuel, and then blasts the expanded airfuel, and then blasts the expanded air--gasgasmixture out the backmixture out the back ..Because everyBecause everyaction has an equal and opposite reaction,action has an equal and opposite reaction,

as the air streams backward the engine isas the air streams backward the engine isforced forwardforced forward ..


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TypeType There are a large number of differentThere are a large number of different

types of jet engines, all of which gettypes of jet engines, all of which get

propulsion from a high speed exhaust jet.propulsion from a high speed exhaust jet.


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Heavy,Heavy,inefficientinefficient

andandunderpoweunderpoweredred

Can run inCan run inshallowshallow

water,water,powerful,powerful,lesslessharmful toharmful to

wildlifewildlife

Most primitiveMost primitiveairbreathing jetairbreathing jetengine.engine.

Essentially aEssentially asuperchargedsuperchargedpiston enginepiston enginewith a jetwith a jetexhaustexhaust..

thermojetthermojet

Basic design,Basic design,misses manymisses manyimprovementimprovement

s in efficiencys in efficiencyand powerand power

SimplicitySimplicityof designof design

GenericGenericterm forterm forsimplesimple

turbineturbineengineengine

turbojetturbojet


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Greater complexityGreater complexity(additional ducting,(additional ducting,usually multipleusually multiple

shafts), large diametershafts), large diameterengine, need toengine, need tocontain heavy blades.contain heavy blades.More subject toMore subject toFODFOD

and ice damage. Topand ice damage. Topspeed is limited due tospeed is limited due tothe potential forthe potential for

shockwaves to damageshockwaves to damageengineengine

Quieter due toQuieter due togreatergreatermass flowmass flowand lower totaland lower totalexhaust speed,exhaust speed,more efficient formore efficient fora useful range ofa useful range ofsubsonicsubsonicairspeeds forairspeeds forsame reason,same reason,

cooler exhaustcooler exhausttemperaturetemperature

First stageFirst stagecompressorcompressor

greatlygreatlyenlarged toenlarged toprovideprovidebypassbypass

airflowairflowaroundaroundengine coreengine core

turbofanturbofan

Needs lots of propellantNeeds lots of propellant--very lowvery lowspecific impulsespecific impulse --typicallytypically 100100--450450 seconds.seconds.

Extreme thermal stressesExtreme thermal stressesof combustion chamberof combustion chambercan make reuse harder.can make reuse harder.Typically requires carryingTypically requires carryingoxidiser onboard whichoxidiser onboard whichincreases risksincreases risks ..

Very few moving parts,Very few moving parts,MachMach 00 to Machto Mach 2525+,+,efficient at very highefficient at very high

speed (> Machspeed (> Mach 1010..00 ororso), thrust/weight ratioso), thrust/weight ratiooverover 100100, no complex, no complex

air inlet, highair inlet, highcompression ratio, verycompression ratio, very

high speed exhaust,high speed exhaust,good cost/thrust ratio,good cost/thrust ratio,

works bestworks best

exoatmospheric whichexoatmospheric whichis kinder on vehicleis kinder on vehicle

Carries allCarries allpropellantspropellants

onboard, emitsonboard, emitsjet forjet forpropulsionpropulsion

roketroket


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Limited topLimited topspeedspeed(aeroplanes),(aeroplanes),

somewhatsomewhatnoisy, complexnoisy, complextransmissiontransmission

High efficiencyHigh efficiencyat lowerat lowersubsonicsubsonic

airspeeds(airspeeds(300300knots plus), highknots plus), highshaft power toshaft power toweightweight

Strictly not a jetStrictly not a jetat allat alla gasa gasturbine engine isturbine engine is

used asused aspowerplant topowerplant todrive (propeller)drive (propeller)shaftshaft

TURBOPROPTURBOPROP

Development ofDevelopment of

propfan enginespropfan engineshas been veryhas been verylimited, typicallylimited, typicallymore noisy thanmore noisy thanturbofans,turbofans,

complexitycomplexity

Higher fuelHigher fuel

efficiency,efficiency,potentially lesspotentially lessnoisy thannoisy thanturbofans, couldturbofans, couldlead to higherlead to higher--

speedspeedcommercialcommercialaircraft, popularaircraft, popularin thein the 19801980ssduring fuelduring fuelshortagesshortages

TurbopropTurboprop

engine drivesengine drivesone or moreone or morepropellers.propellers.Similar to aSimilar to aturbofan withoutturbofan without

the fan cowlingthe fan cowling ..

PROPFANPROPFAN


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Noisy, inefficientNoisy, inefficient(low(lowcompressioncompression

ratio), worksratio), workspoorly on apoorly on alarge scale,large scale,valves on valvedvalves on valveddesigns weardesigns wearout quicklyout quickly

Very simpleVery simpledesign,design,commonly usedcommonly used

on modelon modelaircraftaircraft

Air isAir iscompressed andcompressed andcombustedcombusted

intermittentlyintermittentlyinstead ofinstead ofcontinuously.continuously.Some designsSome designsuse valvesuse valves ..

PULSJETPULSJET

Extremely noisy,Extremely noisy,parts subject toparts subject toextremeextrememechanicalmechanical

fatigue, hard tofatigue, hard tostart detonation,start detonation,not practical fornot practical forcurrent usecurrent use

MaximumMaximumtheoreticaltheoreticalengineengineefficiencyefficiency

Similar to aSimilar to apulsejet, butpulsejet, butcombustioncombustionoccurs as aoccurs as a

detonationdetonationinstead of ainstead of adeflagrationdeflagration ,,may or may notmay or may notneed valvesneed valves

PULSPULSDETONATIONDETONATIONENGINEENGINE


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Still inStill indevelopmentdevelopmentstages, must havestages, must havea very high initiala very high initial

speed to functionspeed to function(Mach >(Mach >66),),cooling difficulties,cooling difficulties,very poorvery poorthrust/weightthrust/weightratio (~ratio (~22),),

extremeextremeaerodynamicaerodynamiccomplexity,complexity,airframeairframedifficulties, testingdifficulties, testingdifficulties/expensdifficulties/expens

ee

Few mechanicalFew mechanicalparts, canparts, canoperate at veryoperate at very

highhighMachMachnumbersnumbers )) MachMach88 toto 1515) with) withgoodgoodefficienciesefficiencies[[11]]

Similar to aSimilar to aramjetramjetwithout awithout adiffuser;diffuser;airflowairflowthrough thethrough theentire engineentire engine

remainsremainssupersonicsupersonic

SCRAMJETSCRAMJET


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Airspeed limitedAirspeed limitedto same rangeto same rangeas turbojetas turbojetengine, carryingengine, carrying

oxidizer likeoxidizer likeLOXLOXcan becan bedangerousdangerous

Very close toVery close toexisting designs,existing designs,operates in veryoperates in veryhigh altitude,high altitude,

wide range ofwide range ofaltitude andaltitude andairspeedairspeed

A turbojetA turbojetwhere anwhere anadditionaladditionaloxidizeroxidizersuch assuch as

oxygenoxygenis addedis addedto the airstreamto the airstreamto increase maxto increase maxaltitudealtitude

TURBOROKETTURBOROKET

Exists only at theExists only at thelab protoypinglab protoypingstage. Examplesstage. ExamplesincludeincludeRBRB545545 ,,SABRESABRE ,,ATREXATREX

Easily tested onEasily tested onground. Very highground. Very highthrust/weight ratios arethrust/weight ratios arepossible (~possible (~1414) together) togetherwith good fuelwith good fuelefficiency over a wideefficiency over a widerange of airspeeds,range of airspeeds,machmach 00--55..55+; this+; thiscombination ofcombination ofefficiencies may permitefficiencies may permitlaunching to orbit,launching to orbit,single stagesingle stage,,

Intake air isIntake air ischilled to verychilled to verylowlow

temperatures attemperatures atinlet beforeinlet beforepassing throughpassing througha ramjet ora ramjet orturbojet engineturbojet engine

PRECOOLEDJETPRECOOLEDJET


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JET ENGINE Senator. Libya

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