Experimental Determination Of Convection Boiling Curves for Water and Ethylene Glycol in a

Rectangular Channel with Localized Heating

ByAndrew T. O’Neill

3-23-05

Topics of Discussion Introduction Experimental Apparatus Experimental Procedure Results Conclusion

Introduction Background

Automotive Application Previous Research

Objective Realistic Conditions Experimental Data

Experimental Apparatus Flow Loop Test Section Heater Instrumentation

Flow Loop

Flow Loop Control Pressure Flow Rate Temperatur

e

Flow Loop Instrumentation Flow Rate

Turbine Flow Meter

Temperature 3 TCs

Test Section

Heater Section

Test Section Instrumentation Pressure

0-100psia 4 TCs

E-type Embedded in Heater Element

Heater Element

(Dimensions in mm)

Heater Thermocouples 4 TCs

3 Along Surface

1 Pair Surface Temp

Heat Flux

Ts T2 T4 T2 0.001m0.005m

qT k

l

T4 T2 394W

m K

0.005m

(Dimensions in mm)

Heater Assembly

Data Acquisition National Instruments

LabView Software PCI-MIO-16E-4 Hardware SCXI Signal Conditioning

1102 Module, 1303 Breakout Box 1124 Module, 1325 Breakout Box

Data Acquisition Cont. Measurements

Flow Rate Temperature

Bulk Fluid Heater

Pressure Control

Bulk Heating Heater Power

Assumptions Steady State Condition

1-D Heat Transfer in Copper Element Stabilized Surface Temp and Heat Flux

Inlet Temp Used as Bulk Fluid Temp Fluid Pressure

Average of Upstream and Downstream Measurements

Experimental Uncertainty Flow Rate / Velocity

±1.9 lpm + 2% of reading ±0.05 m/s + 2% of reading

System Pressure ±0.017 atm + 0.86% of reading

Bulk Temperature ±1.6°C

Heater Temperature ±1.5°C to actual ±0.18°C relative

Heat Flux ±0.142 W/cm2 + 5% of reading

Experimental Procedure Loop Filling

Cleaning Evacuating Degassing Working Fluid

Data Collection

Loop Filling Cleaning

Acetone Solvent Evacuating

Dual Stage Rotary Vane Vacuum Pump -5°C Cold Trap

Degassing Pressure Vessel After Filling

Data Collection Bulk Conditions Set

Pressure Inlet Temperature Flow Rate

Systematic Curve Development 1000 Samples/s 250 Samples/update 900 Updates After Heat Flux Change 100 Updates Recorded

Data Collection Cont.

Data Collection Cont.

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    

Bulk Conditions for Water

Mean Velocity

Data Collection Cont.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      

Bulk Conditions for Ethylene Glycol

Mean Velocity

Water Results Effect of Velocity Effect of Subcooling

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 Convergence of Boiling Curves

Around 20°C Wall Superheat Independent of:

Velocity Inlet Temperature Pressure

Photographic Study Varied Boiling Behavior Same Heat Flux and Wall Superheat

Ethylene Glycol Results Effect of Velocity Effect of Subcooling

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 Boiling Heat Transfer

Independent of: Velocity Inlet Temperature

Dependant on System Pressure Photographic Study

Similar Boiling Behavior with Varied Wall Superheat.

Comparison of Water to Glycol Similar Response to Velocity Increased Wall Superheat with

Boiling Effect of System Pressure Effect of Subcooling

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 Experimental Apparatus

Successfully Constructed Representative of Engine Cooling

System Boiling Curves Developed for Water

and Water Ethylene-Glycol Mixture Showed Effects of:

Velocity Pressure Subcooling

Questions?