PROBLEM 2.48
As shown in Fig. P2.48, an oven wall consists of a 0.635-cm-thick layer of steel (s = 15.1
W/mK) and a layer of brick (b = 0.72 W/mK). At steady state, a temperature decrease of 0.7oC
occ
PROBLEM 2.69
Steam in a piston-cylinder assembly undergoes a polytropic process. Data for the initial and
final states are given in the accompanying table. Kinetic and potential energy effects are
neg
4.86 Three return steam lines in a chemical processing plant enter a collection tank operating at
steady state at 1 bar. Steam enters inlet 1 with flow rate of 0.8 kg/s and quality of 0.9. Steam
enter
Midterm
MAE 221 Thermodynamics
Wednesday, 9 November 2005 10:00am 10:50am FC004 Closed Book Closed Notes
Be sure to state all assumptions, and draw and label relevant schematics, processes, etc. 1. A
Problem 2.85
A concentrating solar collector system, as shown in Fig. P2.85, provides energy by heat transfer
to a power cycle at a rate of 2 MW. The cycle thermal efficiency is 36%. Determine the pow
PROBLEM 2.70
Air expands adiabatically in a piston-cylinder assembly from an initial state where p1 = 100
lbf/in.2, v1 = 3.704 ft3/lb, and T1 = 1000 oR, to a final state where p2 = 50 lbf/in.2 The pro
4.126 A tank of volume 1.2 m3 initially contains steam at 8 MPa and 400oC. Steam is
withdrawn slowly from the tank until the pressure drops to p. Heat transfer to the tank contents
maintains the tempe
PROBLE M 114-3
4.43 Air expands through a turbine from 8 bar, 960 K to 1 bar, 450 K. The inlet velocity is
small compared to the exit velocity of 90 mfs. The turbine operates at steady state and devel
PRO§LE M 4. 4-0
4.40 Oxygen gas enters a well-insulated diffuser at 30 lbﬁ’in.2, 440°R, with a velocity of
950 ft/s through a flow area of 2.0 in.2 At the exit, the ﬂow area is 15 times the inlet area
PROBLE M 4-. 4-3
4.45 Steam enters a turbine operating at steady state at 700°F and 450 lbf/in.2 and leaves as a
saturated vapor at 1.2 le‘L/in.2 The turbine develops 12,000 hp, and heat transfer fr
PRoﬁLEM 4-. S‘l
4.51 Steam at l8001bf/in.2 and 1100°F enters a turbine operating at steady state. As shown in
Fig. P451, 20% of the entering mass ﬂow is extracted at 600 lbf/in.2 and 500013. The rest
PROBLEM 4-58
4.58 Air enters a compressor operating at steady state with a pressure of 14.7 lbf/in.2, a
temperature of 80°F, and a volumetric ﬂow rate of 18 ft3/s. The air exits the compressor at a
pr
PROBLEM 4.5?
4.57 At steady state, a well-insulated compressor takes in nitrogen at 60°F, 14.2 lbf/in.2,
with a volumetric ﬂow rate of 1200 ftsfmin. Compressed nitrogen exits at 500°F, 120
lbf/in.
4.62 Air, modeled as an ideal gas, is compressed at steady state from 1 bar, 300 K, to 5 bar, 500
K, with 150 kW of power input. Heat transfer occurs at a rate of 20 kW from the air to cooling
water c
4.69 During cardiac surgery, a heart-lung machine achieves extracorporeal circulation of the
patients blood using a pump operating at steady state. Blood enters the well-insulated pump at a
rate of 5
4.41 Air modeled as an ideal gas enters a well-insulated diffuser operating at steady state at 270
K with a velocity of 180 m/s and exits with a velocity of 48.4 m/s. For negligible potential
energy e
PROBLEM 4:35
4.35 Helium gas ﬂows through a well-insulated nozzle at steady state. The temperature
and velocity at the inlet are 550°R and 150 ft/s, respectively. At the exit, the temperature
is 400°R
4.34 Air with a mass flow rate of 2.3 kg/s enters a horizontal nozzle operating at steady state at
450 K, 350 kPa, and velocity of 3 m/s. At the exit, the temperature is 300 K and the velocity is
460
4.13 As shown in Fig. P4.13, river water used to irrigate a field is controlled by a gate. When
the gate is raised, water flows steadily with a velocity of 75 ft/s through an opening 8 ft by 3 ft.
If
4.16 Air enters a one-inlet, one-exit control volume at 6 bar, 500 K, and 30 m/s through a flow
area of 28 cm2. At the exit, the pressure is 3 bar, the temperature is 456.5 K, and the velocity is
300
4.14 Figure P4.14 shows a two-tier fountain operating with basins A and B. Both basins are
initially empty. When the fountain is turned on, water flows with a constant mass flow rate of 10
kg/s into b
4.18 Refrigerant 134a enters the evaporator of a refrigeration system operating at steady state at
4oC and quality of 20% at a velocity of 7 m/s. At the exit, the refrigerant is a saturated vapor at
a
4.21 Air enters a compressor operating at steady state with a pressure of 14.7 lbf/in.2 and a
volumetric flow rate of 8 ft3/s. The air velocity in the exit pipe is 225 ft/s and the exit pressure is
15
4.28 At steady state, air at 200 kPa, 325 K, and mass flow rate of 0.5 kg/s enters an insulated
duct having differing inlet and exit cross-sectional areas. The inlet cross-sectional area is 6 cm2.
At
PROBLEM +31
4.31 Steam enters a nozzle operating at steady state at 20 bar, 280°C, with a velocity of 80 m/s.
The exit pressure and temperature are 7 bar and 180°C, respectively. The mass ﬂow rate i
4.70 A pump is used to circulate hot water in a home heating system. Water enters the wellinsulated pump operating at steady state at a rate of 0.42 gal/min. The inlet pressure and
temperature are 14.