Theory of turbo machinery / Turbomaskinernas teori … / Kraftverksteknik / JK A real engine…...

Theory of turbo machinery / Turbomaskinernas teori

Gas turbines

LTH / Kraftverksteknik / JK

Gas turbineVolvo VT 4400

– Fuel: Natural Gas– P = 12.5– Tin = 660 K– Massflow = 20 kg/s


Simple Cycle

Compressor

h

Expander

s

p1

p2

Air

Combustor

Fuel


Ideal Cycle

a) Compression and expansion are reversible and adiabatic, i.e. isentropic

b) The change of kinetic energy of the working fluid between the inlet and outlet of each component is negligable.

c) Pressure losses are neglected.d) The working fluid is the same in the entire cycle and it is a

perfect gas with constant specific heats.e) The mass flow of gas is the same throughout the cyclef) The heat-exhanger is a counterflow type with “complete”

heat transfer


Ideal Cycle

0ΔQ h W= +

( ) ( ) ( )12 02 01 2 1 2 1pW h h h h c T T= − − = − − = − −

( ) ( )23 3 2 3 2pQ h h c T T= − = −

( ) ( )34 3 4 3 4pW h h c T T= − = −

Compressor

Combustor

Expander (turbine)

steady flow energy equation


Ideal Cycle

( )1 32

1 4

TT rT T

γ γ−= =

32

1 4

pprp p

= =where r is pressure ratio

The efficiency equals the ratio of net work output and supplied heat

( ) ( )( )

3 4 2 134 12

23 3 2

p p

p

c T T c T TW WQ c T T

η− − −−

= =−

Cycle efficiancy


Ideal Cycle

( ) ( )4

14 1 1 1

24 4 22

1 1 1

111 1 1 1

1 1

TT T T T

T rT T TTT T T

γ γ

η−

⎛ ⎞−⎜ ⎟− ⎛ ⎞⎝ ⎠= − = − = − = − ⎜ ⎟⎛ ⎞ ⎛ ⎞ ⎝ ⎠− −⎜ ⎟ ⎜ ⎟

⎝ ⎠ ⎝ ⎠

i.e. a function of r and γ only!


Ideal Cycle

( ) ( )( )

( )( )13 4 2 1 31

1 1 1

11 1P

T T T T TW rc T T T r

γ γγ γ

−−

− − − ⎛ ⎞= = − − −⎜ ⎟⎝ ⎠

( ) ( )34 12 3 4 2 1p pW W W c T T c T T= − = − − −

Normalising with 1PC T

Net work

3

1

T tT

=


Ideal Cycle


Recuperated Cycle

Compressor Expander

Heat Exchanger


Evaporative Cycle

Compressor Expander

Liquid water

Evaporator


O2 fired cycle Cycle

ASU

Air

O2

N2

Compressor Expander

EGR


H2 fired Cycle

Reformer

Air

CmHnH2O(Air)

Compressor Expander

H2, CO2, (N2)

CO2Separation

Combustor

H2 (N2)


Recuperated Cycle


Physics of combustion

• Spray formation• Evaporation• Mixing• Ignition• Combustion• Emission formation• Temperature

distribution• ……..

Air blast atomizer, diffusion combustion


Schematic combustor

FUEL INJECTOR

DILUTION ZONE

AIR

DIFFUSERAIR SWIRLER

COOLING SLOTAIR CASING

LINER

INTERMEDIATE ZONE

PRIMARY ZONE


Spray formation, breakup and vaporization in cross-flow duct typical for LPP modules

LPP module of VT4400


Combined cycles

Magnus Genrup 19

Steam Turbine (condensing)

100 % fuel

15 °CGas Turbine

2-pressure HRSG

520…540 °C

27 °C

31 °C

Courtesy to Alstom


Type of propulsion plant

2009-10-12 Magnus Genrup 20

Rolls-Royce, The Jet Engine


Whittle W1



TurbojetRolls-Royce Olympus



JAS Gripen engine - RM12


Courtesy to Volvo Aero


Turboprop



Rolls-Royce Trent 500A340-500/600



HSS Passenger shipsSiemens SGT-500


Stena Carisma

Luciano FedericoSiemens SGT-500

http://www.ship-technology.com/projects/luciano/index.html


A real engine…


Opt pressure ratio’sCOT=1643K

• S/C η: 25.06

• C/C η: 18:08

• Spec. work: 14.36

2 stage compressor turbine, rotor blade temp <900°C, COT-SOT = 70°C

.3

.32

.34

.36

.38

.4

Ther

mal

Effi

cien

cy

300 350 400 450 500

Specific Power [kW/(kg/s)]

Pressure Ratio = 10 ... 26 Burner Exit Temperature = 1473 ... 1773 [K]

147

3

152

3

157

3

162

3

167

3

172

3

177

3

0.51 0.52

0.53

0.54

0.55

0.56

Dotted Lines = (PWSD*0.985*0.985+cp_val7)/(WF* [g/(kN*s)]

10

12

14

16

18

20 22

24 26 WCLTq2 iterated for T_m_T=1173ZW2Rstd iterated for W2=100WCLNq2 iterated for cp_val1=70

Example!ηcc

Theory of turbo machinery / Turbomaskinernas teori … / Kraftverksteknik / JK A real engine…...

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