NIE 3 124ThermodYnamics Fatl2007- Exam#1 Name:
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onthe massor sizeof the system' 1.PropE[esthat depend @Pxtensive b) intensive c) sPecific d) molar 2. Positivework is work doneon the system' a) True
1.30 Figure P130 shows a gas contained in a vertical piston—
cylinder assembly. A vertical shaft whose cross—sectional area
is 0.8 cm2 is attached to the top of the piston. Determine the
magnitude, F, of the ﬁorce acting on the shaft, in N, required if
ME 3124Thermodynamics FaII2007-Exan#2 l. (40 points) Air asan ideal gasis compressed from StateI wherethe pressure is 0.lMPa andthe temperatwe 300Kto State wherethepressure 0.45MPa 480K. is 2 is and Kinetic andpotentialenergyeffectsarenegligible. a)
40.32 Figure P'lU.32 shows the schematic diagram of a vapor—
compression refrigeration system with two evaporators using
Refrigerant 134a as the working fluid. This arrangement is
i used to achieve refrigeration at two different temperatures 7
with a sing
Due Monday October 8th in class. Read Chapter 6, All Sections.
1. At steady state, a 750 MW power plant receives energy by heat transfer from the combustion of fuel at an average temperature of 316 C. The plan discharges energy by heat
Read Chapter 4, All Sections. Due in class Monday, September 17th .
1. Consider a two-phase liquid-vapor mixture of ammonia where the specific volume is 1.0
(a) Determine the quality if the temperature is 100o F. Show all work.
Due Wednesday, October 25th , in class. Read Chapter 8, Sections 8.1 8.3.
1. Consider a turbine operating at steady state. Water enters the turbine at 20 bar and
400 C and exits at 1.5 bar. You can neglect stray heat transfer and the ch
Due Monday, October 15th , in class.
1. One-tenth kilogram of a gas in a piston cylinder assembly undergoes a Carnot power cycle
for which the isothermal expansion occurs at 800K. The change is specific entropy of the
gas during the iso
Read chapters 1 and 2, all sections. Due in class Monday September 3rd .
1. The specific volume of water vapor at P = 0.3 MPa and T = 160o C is = 0.651 m3 /kg
and the water vapor occupies a volume of V = 2 m3 .
(a) Draw a figure and cle
Due Monday November 12th in class.
Read Chapter 9.1, 9.2, 9.5, 9.6.
1. Consider an air-standard Otto cycle with a compression ratio of 9. At the beginning of
the compression p1 = 100 kPa and T1 = 300 K. The heat addition per unit mass o
Due Monday, December 3rd in class.
Read Chapter 12 sections 12.1 12.7.
1. Consider a piston cylinder apparatus that contains a 2 kg mixture of 30% N2 , 40% CO2
and 30% O2 on a mass basis. The mixture is compressed adiabatically from 1
Due in class, Monday, November 19th .
Read Chapter 10 sections 10.1, 10.2, 10.3, and 10.6.
1. Consider an ideal vapor-compression refrigeration cycle that uses refrigerant 134a as the
working fluid. Refrigerant enters the compressor at
Read Chapter 8, Sections 8.1, 8.2, 8.3. Due in class Wednesday October 31.
1. Consider an ideal Rankine cycle with water as the working fluid. The condenser pressure
is 6 kPa, and saturated vapor enters the turbine at 10 MPa.
(a) Draw a
Due Monday, December 10th in class.
Read Chapter 13 sections 13.1 13.2.
1. Air at 1 atm with a dry-bulb temperature of 82 F and a wet-bulb temperature of 68 F
enters a duct with a mass flow rate of 10 lb/min and is cooled at constant p
627 Air in a piston—cylind er assemny and modeled as an ideal
gas undergoes two internally reversible processes ‘“ “MH-
— from state 1, where T; = 290 Km = lbar. @333 T1 : 2% O k;
— Process 1-2.: Compression to p; = 5 bar during whick ‘0 | : 1 bar
[2' ‘ I3" 12.13 As illustrated in Fig, P1313, an ideal gas mixture in a
pist on—cylinder assembly has a molar analysis of30‘i’o carbon (Twat;
dioxide (00;) and ?0% nitrogen (N2).The mixture is cooled
at constant pressure from 425 to 325 K. Assuming
Answers to Assigned Problems from Chapter Thirteen
Annual CO2 output per automobile = 9,300 lb/y based on: modeling gasoline as octane (C8H18); 12,000 miles per year; 25 miles/gal. (a) Rxn: (0.4 CH3OH + 0.5 C2H5OH +0.1 N2) + 2.793 (O2+3.7
Reference Handout for ME3124 tests
THE FIRST LAW Conservation of Energy for a Closed System:
Net heat input
Net work output
Change in energy of the system
Conservation of Energy for a Control Volume:
Rate of energy in due to mass transfer
3.10 For H30, determine the Speciﬁed property at the indicated
state. Locate the state on a Sketch of the T—u diagram.
(a) p = 300 kPa, 1,- = 0.5 m3ﬂ<g Find T, in °C.
(13);) = 28 MPa, T = 200°C. Find 1;, in m3rkg.
(c) p = 1 MPa, T = 405°C. Find u,in
4.37 As shown in Fig. P437", air enters the diffuser of a jet
engine operating at steady state at 13 kPa, 216 K and a
1welccity of 265 mfs, all data corresponding to high-altitude
ﬂight. The air ﬂows adiabatically through the diffuser and
achieves a t