 # Assignment 6

```Assignment Set 6
8.27 Steam is the working fluid in the ideal reheat cycle shown in Fig. P8.27 together with
operational data. If the mass flow rate is 1.3 kg/s, determine the power developed by the cycle,
in kW, and the cycle thermal efficiency.
KNOWN: An ideal reheat cycle operates with steam as the working fluid. Operational data are
provided.
FIND: Determine the power developed by the cycle, in kW, and the cycle thermal efficiency.
SCHEMATIC AND GIVEN DATA:
T
1 Ɣ
State
p
(bar)
T
(oC)
h
(kJ/kg)
1
140
520.0
3377.8
2
15
201.2
2800.0
3
15
428.9
3318.5
4
1
99.63
2675.5
5
1
99.63
417.46
6
140
3
Ɣ
p = 140 bar
Ɣ
p = 15 bar
6Ɣ
5Ɣ
2
p = 1 bar
Ɣ
4
s
431.96
Fig. P8.27
p3 = p2 = 15 bar
Reheat
Section
Q in
3
p2 = 15 bar
Steam
Generator
1
p1 = 140 bar
2
Turbine
1
Turbine
2
W t
4
Q out
6
p6 = p1 = 140 bar
Condenser
Pump
5
p5 = p4 = 1 bar
x5 = 0 (saturated liquid)
W p
1
p4 = 1 bar
ENGINEERING MODEL:
1. Each component of the cycle is analyzed as a control volume at steady state. The control
volumes are shown on the accompanying sketch by dashed lines.
2. All processes of the working fluid are internally reversible.
3. The turbine and pump operate adiabatically.
4. Kinetic and potential energy effects are negligible.
5. Condensate exits the condenser as saturated liquid.
ANALYSIS:
The net power developed by the cycle is
Wcycle
Wt1 Wt2 Wp
Mass and energy rate balances for control volumes around the two turbine stages and the pump
give, respectively,
(h1 h2 )
Turbine 1: Wt1 m
(h h )
Turbine 2: W
m
t2
Pump:
Wp
3
4
(h6 h5 )
m
where m is the mass flow rate of the steam. Solving for the net power developed by the cycle
yields
Wcycle
Wcycle
[(h1 h2 ) (h3 h4 ) (h6 h5 )]
m
kJ
kJ
kJ º 1 kW
§ kg ·ª
(3318.5 2675.5)
(431.96 417.46) »
¨1.3 ¸«(3377.8 2800.0)
s
kg
kg
kg
¹¬
¼ 1 kJ/s
Wcycle = 1568.2 kW
The thermal efficiency is
K
Wcycle
Q
in
The total rate of heat transfer to the working fluid as it passes through the steam generator and
reheater is determined using mass and energy rate balances as
Qin
>(h1 h6 ) (h3 h2 )@
m
2
Solving for rate of heat transfer gives
Qin
kJ 1 kW
§ kg ·
= 4503.6 kW
¨1.3 ¸>(3377.8 431.96) (3318.5 2800.0)@
s ¹
kg 1 kJ/s
The thermal efficiency is then
K
Wcycle
Q
in
1568.2 kW
= 0.3482 (34.82%)
4503.6 kW
3
``` # 蒸気用チェック弁 AXT1274AX8／AXT1274AX54 Check valve for steam # PRESS RELEASE EthosEnergy fulfils GE Frame 7EA gas turbine parts # Some thermo exam type questions Some fairly straight forward # SST-900 steam turbine for economical production of heat and power # Q1. Three energy sources used to generate electricity are given in 