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wre WOH
ME Board Problem .
‘ past drawn into a gas turbine working on the con
Ai 5 1°C and compressed to 5.7 bar, Th
bar ly is 680°C. Taking expansion and co
a8 ka/kg-K, Cy = 1.055 b/kg-K, cal
a at constant pressure,
A. 472 Ki/kg C. 501 kijkg
B 389K/kg D. 489 ki/kg
stant Pressure
€ temperature at th
Mpression to be adia
Iculate the heat ener
Cycle at 4
'e end of heat
batic where Cc
SY Supplied per
Heat Energy Supplied:
Q® = mC (-t)
Solving for t, :
kA
wie eae
Tt P
144
a (22) oe
214273 1
T, = 483.41 K
Ts; = 680 + 273 = 953 K
thus;
Qh = 1.005 ( 953 - 483.41 )
© Qa = 471.94 ki/kg
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past ME Board Problem
he compressor inlet ait temperature in a gas turbine plant is 99°C.
cakculate the compressor air exit temperature if it requires 400 kJ/kg of
work.
Cc. 500°C
D. 599°C
We= mC, (T2-Tr)
400 = 1(1) [T.-( 99 + 273)]
thus;
Ty = 499°C
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- turbine power plant operating on the Brayton cycie delivers 15 MW to
gendby electric generator. What is the mass flow rate and the volume
ie rate of air if the minimum and maximum pressures are 100 kPa and
500 KPa respectively, and temperatures of 20°C and 1000°C.
51.97 ka/s , 26.88 m/s C. 41.97 kg/s , 26.88 m’/s
; 36.98 kg/s, 28.99 m/s D. 46.98 kg/s , 28.99 m’/s
pv = mRT
Solving for m:
ke}
he (2) «
4 Pa
Ad
1000-273 _ ( 03) 4
% \ 100
T, = 803.75K
Wi = mC (T3-Ta)
15000 = ™ qa) ¢ 1273 - 803.75 )
m = 31.97 kg/s
then;
100V = 31.97 (0.287) (20+ 273)
thus; ;
w V = 26.88 1s
Scanned with CamScanner ME Board Problem |
20. erat air-standard Brayton cycle the inlet temperature and pressure are
20°C and 101.325 kPa. The turbine inlet conditions are 1200 kPa and 900°,
Determine the air flow rate if the turbine produces 12 Mw. .
A. 2141 ka/s C. 19.25 kg/s
B. 20.20 kg/s D. 18.10 kg/s
Satine
We = mC,(T3-T4)
Solving for T.:
ka
BL (B\e
7, (Py
9004273 -( 1200 jis
Ts 101.325
Ts = 578.89 K
then; .
12000 = m (1)( 1173 - 578.89 )
thus;
“ M= 20.20 kg/s
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past ME Board Problem
pressure ratio is 10.
48.21 %
B. 50.16 %
thus ;
# @ = 48.21%
What is the thermal efficiency
of an air-standard Brayton cycle if the
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In a simple gas turbine plant working on
air is taken into the compressor at 1 bar,
the Ideal constan
16°C and detivere
e gy
the temperature at turbine inlet is 700°C, Calculate tet 54 bar
efficiency ? Take k = 1.4, idea thet
A 38.23% C. 45.66 %
B. 42.61% . D. 35.38 %
T,-T
e1-4c04
“ 13-Th
Solving for Tz, T3 and T, :
kt
2a
14-1
Re ye
16+273 7
T, = 467.90kK
kal
Te (Pye
Ts (Py
14-1
ro (Gaye
700+273 1
Ts = 600.98 K
then;
- _ 600.98- 289
© = 1° 973-467.90
= 0.3823
thus;
we = 38.23%
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14. ME Board Problem
what is the efficiency of the compressor in a gas turbine plant # 1.
compressor power is 300 kW. Power input is 400 kW. é
A 75% C. 85%
D. 70 %
B. 80%
_ 300
400
thus; :
7 & = 0.75 oF 75%
_—
—
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18, Past ME Board Problem ,
‘An ideal gas turbine operates with @ pressure ratio of 10 and the e
input in the high temperature heat exchanger is 300 kW. Calculate the air
flow rate for 2 temperature limits of 30°C and 1200°C.
A 0.25 kg/s C. 0.41 kg/s
B. 0.34 kg/s D. 0.51 kg/s
& = mG(T-Te) Q 200%W
Solving for T2 : ~
k-l
Rh. {h)t
tT (Ry
papvet " Generator
_ ae (io° 14
301273}
Tz = 585K
then;
300 = m (1) ( 1473 - 585)
thus;
= Mm = 0.34 kg/s
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