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Report 7 Two flasks. Team Taiwan Franklin Liou. Problem # 7. H. H. h. ?. ?. Investigate and describe in which tube the water goes up faster and in which the final height is greater. How does this effect depend on the time of heating?. Overview. Introduction Experiment - PowerPoint PPT Presentation
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Report 7Two flasks
Team Taiwan
Franklin Liou
2
Problem # 7
H H
h? ?
Investigate and describe in which tube the water goes up faster and in which the final height is greater. How does this effect depend on the time of heating?
3
Overview• Introduction• Experiment– Experimental Setup– Experiment
• Results and Discussion• Conclusions & Summary
4
Experiment Setup
•1300ml flask (200ml water)•Hot plate•Oil bath (for heating dry flask)
The heating apparatus and sensors•Pressure sensor•Thermocouple
5
Experiment Setup
Transparent tube and long ruler
Water reservoir
6
Experiment
• Initial conditions: 100 oC• Conditions– Flask with and without water– Heating time after reaching 100 oC
(1min, 2min, 5min)• Data– Temperature-Time curve– Pressure-Time curve– Water height-Time curve
7
Experiment Results: Dry Flask
• Height-Time curve is roughly a saturation curve
• Maximum height: 1.72m
0 200 400 600 800 1000 1200 1400 1600 18000
20406080
100120140160180200
dry, 2min dry, 5min
heigh
t (m
)
time (s)
•Temperature-Time curve is roughly an exponential decay•Max: 103oC, Min:31oC•Decay rate:0.0026
0 300 600 900 1200 1500
40
60
80
100 Dry, 2min Dry, 5min exp fit
Tem
pera
ure
(o C)
Time (s)
Dry Flask after heated at 100 oC for 2 minutes
Experiment Results: Dry Flask
• Pressure-Time curve is roughly an exponential decay• Maximum pressure: 103 kPa• Minimum pressure: 84 kPa
8
19P kPa
9
Experiment Results: Wet Flask
0 500 1000 1500 2000 2500 3000 3500 400030
40
50
60
70
80
90
100
wet, 1min wet, 2min wet, 5min
Tem
pera
ture
(o C)time (s)
0 500 1000 1500 2000 2500 3000 35000
2
4
6
8
10
wet, 1min wet, 2min wet,5min
heigh
t (m
)
time (s)
• Height-Time curve is roughly a saturation curve
• Maximum height: 8.6m
•Temperature-Time curve is roughly an exponential decay•Max: 100oC, Min:31oC•Decay rate:0.0011
10
Experiment Results: Wet Flask
• Pressure-Time curve is roughly an exponential decay
• Maximum pressure: 101 kPa• Minimum pressure: ~ 5 kPa
96P kPa
11
Results and Discussion
dT T Hdt
tR H RT t T T T e
31.5 304.5oRT C K
71.5H RT T K We can obtain the decay rate , and hence the approximate T(t) function
0 300 600 900 1200 1500
40
60
80
100 Dry, 2min Dry, 5min exp fit
Tem
pera
ure
(o C)
Time (s)
Dry Flask after heated at 100 oC for 2 minutes
•Newton’s Law of Cooling:
Square of residual: 0.99974
12
Dry flask• Ideal gas law: expansion of dry air~1900Pa
PV nRT 0 0 1V hA P h g n RT
•V0: initial volume•P0:initial pressure•N1: initial mole of gas
h h
•A cross section of tube•R: Ideal gas constant•T: temperature at a given time
0( ) th t h B C De
tR H RT t T T T e
13
Dry Flask Results
0 300 600 900 1200 1500
0.5
1.0
1.5
2.0
2.5
Heated for 5 min
Hei
ght (
m)
Time (s)
Heated for 2 min
Ideal Gas Assumption
H=64.86-5.00*Sqrt(159.67+7.36*Exp(-0.0312t))
0( ) th t h B C De
14
Wet flask
5132exp 20.386 ot
R H R
P h gT T T e
•Antoine equation:
•Assuming water vapor replaces all air
0( ) expexp( / )Dh t h B C
E F t G
•Water vapor can fill almost all volume -> condense -> large pressure difference~101300Pa
5132exp 20.386P kT
133.3 , ( , )k Pa T in K P in Pa
15
Wet Flask Results
0 500 1000 1500 2000 2500 3000 35000
2
4
6
8
10
wet, 1min wet, 2min wet,5min
heigh
t (m
)
time (s)
0( ) expexp( / )Dh t h B C
E F t G
16
Comparison of Wet and Dry Flask
0 500 1000 1500 2000 2500 3000 3500
0
2
4
6
8
10
wet, 1min wet, 2min wet, 5min dry, 2min dry, 5min
heigh
t (m
)
time (s)
17
Results and Discussion
Time span of boiling at100oC/ maximum height
1min 2min 5min
Dry Flask 1.72m 1.69mTheoretical Dry Flask (Ideal gas law)
2.25m 2.25m
Wet Flask 8.65m 8.66m 8.42mTheoretical Wet Flask (Antoine equation)
9.12m 9.12m 9.12m
18
Conclusions & Summary• Two flaks : two mechanisms–Dry flask: expansion of air~ 1.9 kPa–Wet flask: condensation of vapor~ 101300 Pa
• Water rises faster in wet flask condition• Maximum water height is greater in wet flask
0 500 1000 1500 2000 2500 3000 3500
0
2
4
6
8
10
wet, 1min wet, 2min wet, 5min dry, 2min dry, 5min
heigh
t (m
)
time (s)
• Maximum water height and water rising speed is independent of time of heating
19
0 300 600 900 1200 1500
0.5
1.0
1.5
2.0
2.5
Heated for 5 min
H
eigh
t (m
)
Time (s)
Heated for 2 min
Ideal Gas Assumption