Transcript Experimental Determination Of Convection Boiling Curves

Experimental Determination Of Convection Boiling Curves
for Water and Ethylene Glycol in a Rectangular Channel
with Localized Heating
By
Andrew T. O’Neill
3-23-05
Topics of Discussion
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Introduction
Experimental Apparatus
Experimental Procedure
Results
Conclusion
Introduction
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Background
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Automotive Application
Previous Research
Objective
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Realistic Conditions
Experimental Data
Experimental Apparatus
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Flow Loop
Test Section
Heater
Instrumentation
Flow Loop
Flow Loop Control
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Pressure
Flow Rate
Temperature
Flow Loop Instrumentation
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Flow Rate
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Turbine
Flow Meter
Temperature
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3 TCs
Test Section
Heater Section
Test Section Instrumentation
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Pressure
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0-100psia
4 TCs
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E-type
Embedded in Heater Element
Heater Element
(Dimensions in mm)
Heater Thermocouples
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4 TCs
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3 Along Surface
1 Pair
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Surface Temp
Ts
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0.001m
T2  T4  T2 
0.005m


Heat Flux
q
 T k
l
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W
T4  T2 394
mK
0.005m
(Dimensions in mm)
Heater Assembly
Data Acquisition
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National Instruments
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LabView Software
PCI-MIO-16E-4 Hardware
SCXI Signal Conditioning
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1102 Module, 1303 Breakout Box
1124 Module, 1325 Breakout Box
Data Acquisition Cont.
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Measurements
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Flow Rate
Temperature
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Bulk Fluid
Heater
Pressure
Control
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Bulk Heating
Heater Power
Assumptions
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Steady State Condition
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1-D Heat Transfer in Copper Element
Stabilized Surface Temp and Heat Flux
Inlet Temp Used as Bulk Fluid Temp
Fluid Pressure
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Average of Upstream and Downstream
Measurements
Experimental Uncertainty
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Flow Rate / Velocity
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System Pressure
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±1.6°C
Heater Temperature
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±0.017 atm + 0.86% of reading
Bulk Temperature
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±1.9 lpm + 2% of reading
±0.05 m/s + 2% of reading
±1.5°C to actual
±0.18°C relative
Heat Flux
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±0.142 W/cm2 + 5% of reading
Experimental Procedure
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Loop Filling
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Cleaning
Evacuating
Degassing Working Fluid
Data Collection
Loop Filling
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Cleaning
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Evacuating
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Acetone Solvent
Dual Stage Rotary Vane Vacuum Pump
-5°C Cold Trap
Degassing
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Pressure Vessel
After Filling
Data Collection
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Bulk Conditions Set
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Pressure
Inlet Temperature
Flow Rate
Systematic Curve Development
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1000 Samples/s
250 Samples/update
900 Updates After Heat Flux Change
100 Updates Recorded
Data Collection Cont.
Data Collection Cont.
Bulk Conditions for Water
Inlet Temperature
50ºC
70ºC
90ºC
100ºC
110ºC
0.5 m/s
1.00atm
1.00atm
1.00atm,
1.41atm,
1.97atm,
2.61atm
1.41atm
1.97atm
1.0 m/s
1.00atm
1.00atm
1.00atm,
1.41atm,
1.97atm
2.0 m/s
1.00atm
1.00atm
1.00atm,
1.41atm,
1.97atm
3.0 m/s
1.00atm
1.00atm
4.0 m/s
1.00atm
1.00atm
Mean Velocity
Data Collection Cont.
Bulk Conditions for Ethylene Glycol
Inlet Temperature
58.8ºC
78.8ºC
98.8ºC
108.8ºC
118.8ºC
128.8ºC
0.5 m/s
1.00atm
1.00atm
1.00atm,
1.34atm,
1.82atm,
2.45atm
1.34atm
1.82atm
2.45atm
1.0 m/s
1.00atm
1.00atm
1.00atm,
1.34atm,
1.82atm
2.0 m/s
1.00atm
1.00atm
1.00atm,
1.34atm,
1.82atm
3.0 m/s
1.00atm
1.00atm
4.0 m/s
1.00atm
1.00atm
Mean Velocity
Water Results
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Effect of Velocity
Effect of Subcooling
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Due to Bulk Temperature
Due to System Pressure
Effect of Pressure
Effect of Velocity
Effect of Velocity
Boiling at 90°C, 1.00atm, and 0.5m/s
Boiling at 90°C, 1.00atm, and 1.0m/s
Effect of Velocity
Boiling at 90°C, 1.00atm, and 2.0m/s
Boiling at 90°C, 1.00atm, and3.0m/s
Effect of Subcooling
Effect of Subcooling
Effect of Subcooling
Effect of Subcooling
Boiling at 90°C, 1.00atm, and 0.5m/s
Effect of Subcooling
Boiling at 90°C, 1.41atm, and 0.5m/s
Effect of Subcooling
Boiling at 90°C, 1. 97atm, and 0.5m/s
Effect of Subcooling
Boiling at 90°C, 2.61atm, and 0.5m/s
Effect of Pressure
Effect of Pressure
Boiling at 90°C, 1.00atm, and 0.5m/s
Boiling at 100°C, 1.41atm, and 0.5m/s
Effect of Pressure
Boiling at 110°C, 1.97atm, and 0.5m/s
Boiling at 120°C, 2.61atm, and 0.5m/s
Summary of Water Curves
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Convergence of Boiling Curves
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Around 20°C Wall Superheat
Independent of:
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Velocity
Inlet Temperature
Pressure
Photographic Study
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Varied Boiling Behavior
Same Heat Flux and Wall Superheat
Ethylene Glycol Results
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Effect of Velocity
Effect of Subcooling
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Due to Bulk Temperature
Due to System Pressure
Effect of Pressure
Effect of Velocity
Effect of Velocity
Boiling of Glycol at 98.8°C, 0.5m/s, and 1.00atm
Boiling of Glycol at 98.8°C, 2.0m/s, and 1.00atm
Effect of Subcooling
Effect of Subcooling
Effect of Subcooling
Effect of Subcooling
Boiling of Glycol at 98.8°C, 0.5m/s, and 1.00atm
Boiling of Glycol at 98.8°C, 0.5m/s, and 1.34atm
Effect of Subcooling
Boiling of Glycol at 98.8°C, 0.5m/s, and 1.80atm
Boiling of Glycol at 98.8°C, 0.5m/s, and 2.45atm
Effect of Pressure
Effect of Pressure
Boiling of Glycol at 98.8°C, 0.5m/s, and 1.00atm
Boiling of Glycol at 108.8°C, 0.5m/s, and 1.34atm
Effect of Pressure
Boiling of Glycol at 118.8°C, 0.5m/s, and 1.80atm
Boiling of Glycol at 128.8°C, 0.5m/s, and 2.45atm
Summary of Glycol Curves
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Boiling Heat Transfer
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Independent of:
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Velocity
Inlet Temperature
Dependant on System Pressure
Photographic Study
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Similar Boiling Behavior with Varied Wall
Superheat.
Comparison of Water to Glycol
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Similar Response to Velocity
Increased Wall Superheat with Boiling
Effect of System Pressure
Effect of Subcooling
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Constant System Pressure
Constant Inlet Temperature
Boiling Behavior at High Subcooling
Similar Response to Velocity &
Increased Wall Superheat
Effect of System Pressure
Subcooling at Constant Pressure
Subcooling at Constant Inlet
Temperature
Boiling Behavior at High
Subcooling
Boiling of Water at 90°C, 2.61atm, 0.5m/s, and 40°C Subcooling
Boiling of Glycol at 98.8°C, 2.45atm, 0.5m/s, and 40°C Subcooling
Conclusion
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Experimental Apparatus Successfully
Constructed
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Representative of Engine Cooling System
Boiling Curves Developed for Water and
Water Ethylene-Glycol Mixture
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Showed Effects of:
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Velocity
Pressure
Subcooling
Questions?