Fall 2009 ME 301 Period: 5 th 6 th
Mayhew Mech Sanders
Open Text Book
One 8.5” x 11” Equation Sheet (both sides)
[No Worked Examples, ALEs or HW allowed]
Laptops Permitted for Calculations & Music Only
[EES is NOT permitted; music must not disturb others.]
NAME_________________
SCORE
Problem 1
Problem 2
Problem 3
Total
BOX .
______ / 45
______ / 40
/ 15
______ /100
PLEASE NOTE:
The problems 1 & 2 are printed on the inside of this folder. Please write their solutions on blank paper provided. Please write the solution to problem 3 on the question sheet.
Please put your name and CM box on each sheet.
Submit your equation sheet and solutions in the folder before you leave.
DO NOT INTERPOLATE! Use the closest value in the tables.

Problem 1 (45 pts)
Consider the reheat STEAM cycle at the right.
Partial data are provided in the table below. Kinetic and potential energies are negligible.
6
STM GEN
3
1
HPT
3
(a) [16 pts] Determine the net work out per unit mass of steam in kJ/kg.
2
3
(b) [10 pts] Determine the thermal efficiency of the cycle.
LPT
3
4
(c) [9 pts] Determine the adiabatic efficiency of the high pressure turbine (HPT).
(d) [10 pts] Determine the exergetic (2 nd Law) efficiency of the high pressure turbine
(HPT).
5
PUMP
3
CNDSR
3
HINT: Only find the property data necessary to complete the computations. Much of the table can be left blank.
7
8
RECALL: Use the closest table value. Don’t interpolate.
State T [°C] P [bars] h [kJ/kg] s
[kJ/(kg K)] a f
[kJ/kg]
0 17 1.013 71.48 0.2535 0
1
2s = 2rev
2
500 60
7
7 2932.2 7.0641
3
4s = 4rev
4
440 7
0.08
0.08 2521.1 8.0511
5
6s
6
0.08
60
60 181.94 other environment (dead state)

Problem 2 (40 pts)
A mass flow of 0.3 kg/s of AIR enters a compressor operating at steady state. State data are noted on the diagram at the right. Kinetic and potential energies are negligible. During operation, the compressor loses
3 kW by heat transfer from its 47 ºC surface.
T
1
= 17 °C p
1
= 1 bar
The specific heat varies with T.
1
(a) [15 pts] Determine the power required by the compressor.
(b) [10 pts] Determine the rate of exergy transport by heat transfer from the compressor.
T b
= 47 °C
𝑄̇ 𝑜𝑢𝑡
= 3 kW
AIR
COMPR
3
(c) [15 pts] Determine the rate of exergy destruction in the compressor.
2
T
0
= 27 °C p
0
= 1 bar
T p
2
2
= 127 °C
= 3 bar

Problem 3 (15 pts)
Answer this question using the T-s diagram below (drawn to scale); you do not need to perform calculations to get full credit.
An ideal Rankine cycle with reheat has a boiler pressure of 3000 kPa and condenser pressure of
10 kPa. The boiler exit temperature is 500 °C, and the reheater exit temp is also 500 °C. The reheat occurs at 500 kPa.
(a) [6 pts] Draw (as close to scale as you can) the cycle on the T-s diagram below.
Steam
500
400
300
200
3000 kPa
1500 kPa
500 kPa
100
10 kPa
0
0.0
2.0
4.0
6.0
8.0
(b) [3 pts] Using a dashed line, alter the drawing for a reheat pressure of 1500 kPa.
10.0
(c) [6 pts] (Circle the correct answer.) If the reheat pressure was increased to 1500 kPa, will: the quality of the steam entering the condenser increase decrease stay same the net work out per kg increase decrease the thermal efficiency increase decrease stay same stay same