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ME 336 EXAM 2,
MARCH 24, 2006
C. BORGNAKKE, ME Dept.
Problem 1 [40 Points]
A low T application runs a powerplant with R22 having a high pressure of 2000 kPa.
The boiler exit is at 100 C and the condenser operates at 40.8 C. There is one open
“feedwater” heater operating at
∼
500 kPa with an exit as saturated liquid at 0 C.
a) Find the extraction fraction of flow in the turbine to go to the FWH.
b) Find the turbine work per mass flow in the boiler.
Problem 2 [30 Points]
An air flow of 5 kg/min at 1500 K, 125 kPa, goes through a constant pressure heat
exchanger, giving energy to a heat engine. The air exits at 500 K and the ambient is at
298 K, 100 kPa. Find the rate of heat transfer delivered to the engine and the power the
engine can produce.
H
Q
W
L
Q
Ambient
HE
1
2
Problem 3 [30 Points]
A Brayton cycle has inlet at 290 K, 90 kPa and the combustion adds 1000 kJ/kg.
a)
How high can the compression ratio be so the highest temperature is below
1700 K?
b) For that compression ratio can a regenerator be used and how much energy
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 Fall '09
 Borgnakke

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