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1. (£0 Deﬁne or describe the following terms with a single phrase or expression. 9 a. adiabatic /V0 heal transier/ Fe mini/l7 I'Vls’M/Qléyc’j ; b. polytropic process ﬂows: fm’ Mil/(A pl/ntmli' c. equilibrium
We ﬂermdyﬂ‘fmw ﬁlial? 0‘; WW’k/‘EE [/MI‘C/ [5 Omaha gm?
J (1. critical point m 7‘72/0 01! ﬁve. MOW/36 ’ J e. intensive property
A Prop? [n (9/6,??lf’fJ/tai? J? [474755
3 f. heat We 5P=m1£anecuf 10%.! if {ff/8'7}, Cami” wg/jﬂm
bw4‘n..c/grf Mote a ‘/?m/)€lell4r€ ﬁ/Jéérfnoc 5 g. List three es 0 thermodynamic work. typ g H i I
POW ﬁlm” »/ m/t ,/ (4 pts) h. What is the speciﬁc enthalpy of H20 at 150°C and 4 MPa (kJ/kg)?
11,: th ’UL (10717504)
_, 3 652.3? + .08/0ﬁ(4030,_ C Q 3 Q. A; 5/52
(4 pts) i. What is the gauge pressure at t1: bottom of a bucket of water 0.3 m deep (kPa)? Ea 79%(3W) {KR
,= 33?: W ; 2,74 2%
M i 4 / £911
A/jL Please!
Be neat, write out equations before inserting numbers, and circle your answers. If you cannot ﬁgure out one part, assume an answer and carry it through the other parts. 47
2. (46%) An inverted pistoncylinder device contains 4 kg of water initially at a pressure of
1500 kPa and temperature of 250°C (State 1). At this state the frictionless piston is pushed down
against a set of stops as illustrated below. Another set of stops is located toward the top of the
cylinder. The ambient pressure and temperature is 101 kPa, 25°C. The cylinder has mass of 180
kg and a pressure of 1000 kPa is required to support the weight of the cylinder if it is
unconstrained. Cool air is blown over the outside of the uninsulated cylinder causing the water
inside to cool until the temperature of the water is 25°C (State 2). If the cylinder comes to rest on
the upper stops stops, the volume is 0.2 m3. a) Does the cylinder come to rest on the upper stops _at its ﬁnal state (State 2)? Show
how you know whether it does or not. 4" X 9 ’V" (14 /m 2/ PM} .I r
b) What is the pressure of the water at its ﬁnal state? 7
A Q What is the‘phase region for the water at State 1, and if it is saturated what is the
quality?
C a) What is the phase region for the water at State 2. and if it is saturated what is the
quality?
J Q What is the phase region of the water at the point where the piston just leaves the
lower stops?
< 9) What is the work for the process (kJ)?
{ 3) What was the change in potential energy of the cylinder per m of downward
movement?
) h) Qualitativer (no numbers) sketch the process on a PV diagram and label end
points. hm) unit) ‘« M'W
‘1 43) Qualitativer (no numbers) sketch the process on a TV diagram and label end
pomts. 9 M .1 m3 ,’q:ﬁT’$T ' 8
T:(§% 1 \l
0
U1
\ 5m$ Lbju <14 , . . ml /
55kt L />’ >4 v’l‘7’pi 5‘ .\\\\\\\\\\\\\\\\\\\\\\‘ f) : , : i3,/é4 < /000 M: I? /¥w‘// “5% Z )4? /l ‘ / Since {PL Vo/amz Lum'ﬁ" )
' ‘ l L“! ’M‘H'l’r", .. ' ljiw r/L' , , _ .Ll: 0 awn/.44
g T« l p T " 5 K ) DIV 4 L 4 /(
r;   7 + .3. 74/7
W1 — z/L‘l' ~ )5" I zxa Problem 2 continued V")
L w High , Sail
3. (30%) Exxon has found a high temperature/pressure under round reservoir of methane
(CH4). Consider an underground pocket having a ﬁxed volume 245‘ 3 that contains 40 lbm of CH4.
The initial temperature is 40°F (State 1). The pocket is then heated by inserting an electrical
resistance heater to a temperature of 75°F (State 2). Y
( Wait/ILA /,l a) If you assumed that the CH4 is an ideal gas at the initial state ﬁnd the pressure in the pocket aqState IXpsia).
b) Is the CH4 an ideal gas in State 2 after the heating? Show your calculations of the compressibility factor.
c) What is the pressure at State 2 (psia)?
d) For the 40 lbm, ﬁnd the change in the total enthalpy of the CH4 from States 12. Assume Constant speciﬁc heat for the CH4, of Cp = 0.53 BTU/lbm°R (Table 3e) and that it
behaves as an ideal gas. ‘ I I Wt...umwmywmamnxm—WWWWVWMMW
1. HI i I ____,r r  (‘mnprmsihiiiu factor. X I l'v/Rl‘ I) l,“ 2,0 3.0 Jpn 5n ml .,u
Reducer! pressure. PR Problem 3 continued ’0 T 535 .. e
25) 7:: f ' 3'47? /’5 7/]: 3/”: : 40"”
f ﬂ /5’45 1% 342. 7 vz /6 [7213“ #7”
25
5 0'] > I 74‘56X4 6,0123% 4/ 7:1/5é +V,'=.036 :7 z: .83
/\/o [70% an lﬂzﬁﬂ/ 7575/ a) ms 0 weawwavwm > S é 51’
or EV’ZmKT‘ 760W5):,?3(40)l7?3535 C] H 6. 7 2352);)514 ‘
4) AH= MHzT.) / i : 40 [gm /. 53 {3% )[75 440)] 4. 34; (W ...
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This note was uploaded on 01/27/2012 for the course ME 326 taught by Professor Schmidt during the Fall '07 term at University of Texas at Austin.
 Fall '07
 Schmidt

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