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RAVI KUMA
GAS TURBINES
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GAS TURBINESThe gas turbine obtains its power by using energygases and air at high temperature and presexpanding in severa rings of moving and fixed b
The "uantity of the wor#ing f uid and speed re"more$ so$ genera y$ a %entrifuga or an axia
emp oyed!After %ompression$ it is re"uired either to invo ume of f uid at %onstant pressure or inpressure at %onstant vo ume! Genera y thpreferred and is attained by in%reasing the tempe
the gases!Apri &'$ ()&* Prof. Ravi Kumar, Department of Mechanical & Industrial En
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+,-.,NENTS ,/ A GAS TURBINE
%ompressor%ombustion %hamber
turbine
%ondenser
Apri &'$ ()&* Prof. Ravi Kumar, Department of Mechanical & Industrial En
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+1ASSI/I+ATI,N
on the basis of %ombustion pro%ess%onstant pressure 2 3ou e4Brayton %y%
%onstant vo ume 2At#inson %y% e5
on the basis of a%tion of expanding gas
impu se turbineimpu se4rea%tion turbine
Apri &'$ ()&* Prof. Ravi Kumar, Department of Mechanical & Industrial En
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7
on the basis of path of wor#ing substan%eopen %y% e
% osed %y% esemi4% osed %y% e
on the basis of dire%tion of f ow
axia f ow 2power p ant 8 aviation5radia f ow
Apri &'$ ()&* Prof. Ravi Kumar, Department of Mechanical & Industrial En
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I I T R o o r k e e
Simp e ,pen +y% e Gas Turbine
Apri &'$ ()&* Prof. Ravi Kumar, Department of Mechanical & Industrial En
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I I T R o o r k e e
Simp e Gas Turbine +y% eaa
Apri &'$ ()&* Prof. Ravi Kumar, Department of Mechanical & Industrial En
4
32
1
p
v1
2
3T
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I I T R o o r k e e = − − −
= − − −
−
= − − − −
= 1 − − −
Apri &'$ ()&* Prof. Ravi Kumar, Department of Mechanical & Industrial En
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I I T R o o r k e e =
= =
− 1 = − 1
− −
=
= 1 − − −
= 1 − = 1 −1
Apri &'$ ()&* Prof. Ravi Kumar, Department of Mechanical & Industrial En
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I I T R o o r k e e = 1 −
1
=
1
= =
Apri &'$ ()&* Prof. Ravi Kumar, Department of Mechanical & Industrial En
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A%tua Brayton +y% e
The f uid ve o%ities are high in turboma%hthe %hange in #ineti% energy between in et anea%h %omponent %annot ne%essari y be imay be ta#en %are by %onsidering stagnationproperties instead of stati% va ues!There are fri%tion osses in turbines and %omp
Apri &'$ ()&* Prof. Ravi Kumar, Department of Mechanical & Industrial En
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A%tua +y% e
Apri &'$ ()&* Prof. Ravi Kumar, Department of Mechanical & Industrial En
1
2
3
4
T
s
2 ’
4 ’
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7a%tua BThere is a sma pressure oss in the %ombustion %hThe mass of gas f ow in the turbine is 2&
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+y% e Air RateAir f ow rate re"uired for per #i owatt hour
=
=
!""
=!""
#$ %& ' ( ) * = +,
-
Apri &'$ ()&* Prof. Ravi Kumar, Department of Mechanical & Industrial En
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he extra wor# supp ied to the %ompressor due to its iis not entire y wastefu be%ause the heat supp%ombustion %hamber is redu%ed!
= − 1
= 1 − 1
= 1 −1
− −
Apri &'$ ()&* Prof. Ravi Kumar, Department of Mechanical & Industrial En
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I I T R o o r k e e = 1 −
./0
/− 2 -3 4
/0/ − 1
= 1 − 1 − 1 − 1
Apri &'$ ()&* Prof. Ravi Kumar, Department of Mechanical & Industrial En
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I I T R o o r k e e
a
Apri &'$ ()&* Prof. Ravi Kumar, Department of Mechanical & Industrial En
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If > %is e"ua to > t the ratio of T 0=T& %an be %awhi%h no wor# is possib e! This resu t in
56+ = =
If r ? 9@ effi%ien%ies are )!'9 and γ ? &!6 the t min is (means that for T & e"ua to ('' the T 0 is *0& 20
Apri &'$ ()&* Prof. Ravi Kumar, Department of Mechanical & Industrial En
N meri% 4&
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Numeri%a 4&A gas turbine power p ant wor#s between the fixed andtemperature imits 0)) and ;)) $ the abso ute pressubeing &)) #.a and 6)) #.a! The isentropi% effi%
%ompressor is )!' and that of turbine is )!'9! Estimate ththerma effi%ien%y if he p ant and the power avaidriving externa oad if the fue %onsumption is &%a orifi% va ue of fue is 6( -3=#g!
Apri &'$ ()&* Prof. Ravi Kumar, Department of Mechanical & Industrial En
eat Ex%hanger +y% e
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eat Ex%hanger +y% ea
Apri &'$ ()&* Prof. Ravi Kumar, Department of Mechanical & Industrial En
( ) (( )43p
2p43pth TTc
TcTTc
−
−−=η
TTx
TT1
TT1
3
1
4
1th −=−=η
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en%e$ effi%ien%y of heat ex%hanger %y% e is nomaximum %y% e temperature and % ear y iin%reases!
As the t in%reases in is not ne%essary to in%rease
Apri &'$ ()&* Prof. Ravi Kumar, Department of Mechanical & Industrial En
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T E ENC
DDD