Performance Analysis of A Turboprop Cycle

P M V Subbarao

Professor

Mechanical Engineering Department

Looking for Best Opportunities to Realize a True Green Engine ……

Turboprop : Just for Fuel Economy

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23 4 5 6 7

p02=p01= p03 = p0∞

T02=T01 = T03 = T0∞

p04 =r0p,comp p0∞ = p05

T04= =0p,comp T0∞

T05

0p,turb0506 TT τ0p,turb0506 rpp

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Performance of A Turboprop

jetT,propT,pT,turbopro FFF

core

pT,turbopro

m

FS

S

f

F

mTSFC

pT,turbopro

fuel

jetpropambientpcore

acjetT,prop

ambientpcore

turbopropturboprop

CCTcm

VFP

Tcm

PC

Share of the Propeller : Work Coefficient

Turbine Pressure Ratio

0.10

0.167

0.25

0.333

0.5

Compressor Pressure Ratio

Cprop

Share of the Jet : Work Coefficient

Turbine Pressure Ratio

0.10

0.167

0.250.3330.5

Compressor Pressure Ratio

Cjet

Total Work Coefficient

Turbine Pressure Ratio0.10

0.167

0.25

0.333

0.5

Compressor Pressure Ratio

Cturbojet

Compactness of A Turboprop

Compressor Pressure Ratio

Sp

ecifi

c T

hru

st :N

.se

c/kgTurbine Pressure Ratio

0.10

0.167

0.25

0.330.5

Fuel Economy of A Turboprop

Compressor Pressure Ratio

TS

FC

: m

g/N

.sTurbine Pressure Ratio

0.10

0.167

0.25

0.33

0.5

Efficiency of A Turbo Prop

Turbine Pressure Ratio0.10

0.167

0.25

0.333

0.50.10

0.167

0.25

0.333

0.5

Turbine Pressure Ratio

Compressor Pressure Ratio

p

o

OPTIMIZATION OF THE IDEAL TURBOPROP

The question now is: what fraction of the total thrust should be generated by the core in order to produce the maximum work output coefficient. The answer to this question is required in order to properly select the size of the turbine or compressor.

0,,,

turbopturbopturbop jetpropturboprop CCC

0,,,

compopcompopcompop jetpropturboprop CCC

Pratt & Whitney PW127G Turboprop

The result is class-leading fuel consumption and low green house emissions.

Specifications

• Type: Three spool, free shaft turboprop • Inlet: Scroll type • Compressor: Twin spool; 1 stage

centrifugal LPC, 1 stage centrifugal HPC • Burner: Annular, reverse flow • Turbine: Three spool, single stage axial

HPT, single stage axial LPT, 2 stage power turbine

• Exhaust: Rear exit, axial flow jet-type outlet

Specifications Contd…

• Power Rating: 3,500 equivalent shaft horsepower at 1,200 rpm

• Mechanical Horsepower Rating: 3,185 horsepower

• Thrust Rating: 1750 lbt • Rated Torque Output: 13,939 lb/ft • Pressure Ratio: 14.5:1 • Specific Fuel Consumption: .44 lb/shp/hr

Turboprop with Regeneration

Philosophy of Fuel Economy

Rocket Propulsion

P M V Subbarao

Professor

Mechanical Engineering Department

No Breathing of air……Travel with no Gravity and no Drag….

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Rocket Thrust• Rocket ejects mass at a given momentum rate

from the nozzle and receives a thrust in the opposite direction.

• Momentum rate of ejects:

ejectsejectsUmM

• There may also be a thrust component due to pressure field in nozzle.

• Thrust may be increased by either increasing ejects (propellant) flow rate or exhaust velocity.

Flow of Ejects

Rocket Motion

Pay Load

Fuel

Nozzle

THE TSIOLKOVSKY ROCKET EQUATION