Propulsion

PROPULSION

1. PROPULSION

2. UNIT-I
AIRCRAFT GAS TURBINES
•Impulse and reaction blading of gas turbines
•Velocity triangles and power output
•Vortex theory
•Choice of blade profile, pitch and chord
•Estimation of stage performance
•Limiting factors in gas turbine design
•Methods of blade cooling
•Matching of turbine and compressor.
•Numerical problems
•University question paper solution

3. Gas Turbines
•Workcanbeextractedfromagasathigher
inletpressuretothelowerbackpressureby
allowingittoflowthroughtheturbine.
•Theworkdonebythegasisequivalenttothe
changeofitsenthalpy.

4. Impulse turbines
Animpulsestageischaracterizedbytheexpansionofthegas
whichoccursonlyinthestatornozzles.
Therotorbladesactasdirectionalvanestodeflectthe
directionoftheflow.
TheyconverttheK.E.ofthegasintoworkbychangingthe
momentumofthegasmoreorlessatconstantpressure.

5. Reaction turbines
•A reaction stage is one in which expansion of the gas takes
place both in the stator & in the rotor.
•The function of the stator is the same as that of the impulse
stage, but the function of the rotor is in two folds

6. Methods of blade cooling
•Convectioncoolingworksbypassingcoolingairthrough
passagesinternaltotheblade.Heatistransferredby
conductionthroughtheblade,andthenbyconvectioninto
theairflowinginsideoftheblade.Alargeinternalsurface
areaisdesirableforthismethod,sothecoolingpathstendto
beserpentineandfullofsmallfins.
[

7. •Avariationofconvectioncooling,impingementcooling,
worksbyhittingtheinnersurfaceofthebladewithhigh
velocityair.Thisallowsmoreheattobetransferredby
convectionthanregularconvectioncoolingdoes.
Impingementcoolingisoftenusedoncertainareasofa
turbineblade,liketheleadingedge,withstandardconvection
coolingusedintherestoftheblade.

8. •Thesecondmajortypeofcoolingisfilmcooling.Thistypeof
coolingworksbypumpingcoolairoutofthebladethrough
smallholesintheblade.Thisaircreatesathinlayer(thefilm)
ofcoolaironthesurfaceoftheblade,protectingitfromthe
hightemperatureair.Theairholescanbeinmanydifferent
bladelocations,buttheyaremostoftenalongtheleading
edge.

9. •Transpirationcooling,thethirdmajortypeofcooling,is
similartofilmcoolinginthatitcreatesathinfilmofcooling
airontheblade,butitisdifferentinthatthatairis"leaked"
throughaporousshellratherthaninjectedthroughholes.
Thistypeofcoolingiseffectiveathightemperaturesasit
uniformlycoverstheentirebladewithcoolair.
•Transpiration-cooledbladesgenerallyconsistofarigidstrut
withaporousshell.Airflowsthroughinternalchannelsofthe
strutandthenpassesthroughtheporousshelltocoolthe
blade.

10. RAMJET PROPULSION
•Operating principle of Ram jet engine
•Sub critical, critical and supercritical operation of Ramjet
•Combustion in Ramjet engine
•Ramjet performance
•Ramjet design calculations
•Introduction to scramjet.
•Numerical Problems
•University question paper solution

11. RAMJET ENGINE

14. SCRAMJET

15. FUNDAMENTALS OF ROCKET PROPULSION
•Operating principle
•Specific impulse of a rocket -Derivation
•Internal ballistics of rocket engines
•Rocket nozzle classification -Explanation
•Rocket performance considerations
•Numerical problems
•University question paper solution

16. SOLID PROPELLANT ROCKET MOTOR

17. DESIGN
•Designbeginswiththetotalimpulserequired,which
determinesthefuel/oxidizermass.Graingeometryand
chemistryarethenchosentosatisfytherequiredmotor
characteristics.
•Thefollowingarechosenorsolvedsimultaneously.Theresults
areexactdimensionsforgrain,nozzle,andcasegeometries.
•Thegrainburnsatapredictablerate,givenitssurfacearea
andchamberpressure.
•Thechamberpressureisdeterminedbythenozzleorifice
diameterandgrainburnrate.
•Allowablechamberpressureisafunctionofcasingdesign.

18. •Thelengthofburntimeisdeterminedbythegrain'web
thickness'.
•Thegrainmayormaynotbebondedtothecasing.Case-
bondedmotorsaremuchmoredifficulttodesign,sincethe
deformation,underoperatingconditions,ofthecaseandthe
grainmustbecompatible.

19. CHEMICAL ROCKETS
•Solid propellant rockets –Selection criteria of solid
propellants
•Hardware components of solid rockets –Propellant grain
design considerations
•Liquid propellant rockets –Selection of liquid propellants
•Cooling in liquid rockets
•Hybrid rockets
•Numerical problems
•University question paper solution

20. LIQUID ROCKET MOTOR

23. ADVANCED PROPULSION TECHNIQUES
•Electric rocket propulsion
•Ion propulsion techniques
•Nuclear rocket
•Solar sail
•Concepts in nozzleless propulsion
•Numerical problems
•University question paper solution
•Revision

24. Electric rocket propulsion
•ELECTRO THERMAL
•ELECTRO MAGNETIC(PLASMA THRUSTERS)
•ELECTRO STATIC(ION PROPULSION

25. ELECTRO THERMAL PROPULSION
Electro-thermalpropulsionsystemsarethosesystemsinwhich
electricalenergyisusedtoheatpropellants,thusproducing
thrust.
Principle
Electro-thermalsystemsheatpropellants,whichproduce
gases.Thegasesarethensentthroughasupersonicnozzle
toproducethrust.

28. Ion propulsion Technique
•Thistechniqueofpropulsionutilizes
electrostaticenergy,i.e.energydueto
electricchargesonmaterialsisusedtopropel
rockets.Sinceionsareusedforthis,the
techniqueisalsocalledasionpropulsion
technique.

30. Nuclear Rocket
•Nuclear energy is used as propellant.

31. Solar sail

32. NOZZLELESS PROPULSION
Nozzleless solid propellant rocket motor

33. THE END