Electrohydrodynamics Laboratory

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Y. Feng and J. YagoobiHeat Transfer Enhancement and Two-Phase Flow

LaboratoryMechanical, Materials, and Aerospace Engr. Dept.

Illinois Institute of TechnologyChicago, USA

Control of Liquid and Liquid/Vapor Flow Distributions With EHD

Conduction Pumping

Electrohydrodynamics Laboratory

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thermal management of parallel evaporators and condensers

correct liquid distribution required among parallel lines

local hot areas and dry-outs due to mal-distribution

EHD pumping as an active control method conduction pumping, a right choice

Motivation

Electrohydrodynamics Laboratory

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EHD Conduction Pump Electrode

Design Schematic

Net flow

Pipewall

Heterochargelayer

Ring ground electrode

Perforatedelectrode

d=4.3 mm

y

x

Electrohydrodynamics Laboratory

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Electrode Picture

Ring ground electrode

Perforated electrode

Electrohydrodynamics Laboratory

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Working Fluid, R-123

e

(S/m)

(m2/V . s)

4.8 2.7E-8 4.8E-8

(Pa . s)

(kg/m3)

hfg

(kJ/kg)

417.6E-6 1464 171.4

Electrohydrodynamics Laboratory

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0

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900

1200

1500

0 3 6 9 12 15 18

Applied Voltage (kV)

Ge

ne

rate

d P

ress

ure

(P

a)

Experimental Data

Pressure Generation in the Absence of a Net Flow

Electrohydrodynamics Laboratory

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Spark Plug

Teflon Spacer

PerforatedElectrode Ring Ground

Electrode Teflon Tube

Brass

0.8 mm

2.5 mm3.6 mm

23.6 mm

152.4 mm

10.2 mm

EHD Conduction Pump with Three Electrode Pairs

Electrohydrodynamics Laboratory

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F

F

REFRIGERANT PUMP

CHILLERSUPPLY

CHILLER RETURN

PRE-HEATER

ACCUMULATOR

CONDENSER

F

P

SIGHT GLASS

SIGHT GLASS

Thermocouple Probe EHD Conduction PumpEHD FilterF FlowmeterP Pressure Transducer

Refrigerant Chiller (water/methanol) ValveSight Glass

REFRIGERANTRESERVOIR

MA

NIF

OLDEHD

P

PCONDENSER

P

F

BRANCH 1

BRANCH 2

TEST SECTION

Flow Distribution Control Apparatus

Utilizing EHD Conduction Pump

Electrohydrodynamics Laboratory

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Experimental Results – Liquid Phase

(mass flux = 100 kg/m2s, T = 25 C)

Electrohydrodynamics Laboratory

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0

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0 2 4 6 8 10 12Time (min)

Mas

s Flu

x (k

g/m

2 s)Flow Distribution, e = 10 kV

Electrohydrodynamics Laboratory

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0 2 4 6 8 10 12

Time (min)

Curr

ent ( A

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4

8

12

16

20

Applie

d V

oltage (kV

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Current Consumption, e = 10 kV

Electrohydrodynamics Laboratory

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0 2 4 6 8 10 12 14Time (min)

Mas

s Flu

x (k

g/m

2 s)Flow Distribution, e = 15 kV

Electrohydrodynamics Laboratory

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Time (min)

Curr

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15

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25

30

Applie

d V

olta

ge (kV

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Current Consumption, e = 15 kV

Electrohydrodynamics Laboratory

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Experimental Results – Liquid/Vapor Phases

(mass flux = 50 kg/m2s, Tsat = 25 C)

Electrohydrodynamics Laboratory

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Pressure drop along EHD pump

15 kV 17 kV 18 kV 20 kV

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0 200 400 600 800 1000 1200 1400

Time (s)

D P (

Pa

)Pressure Drop Along EHD Conduction Pump

and Branch Tube, Vapor Quality = 6%

Electrohydrodynamics Laboratory

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0 200 400 600 800 1000 1200 1400Time (s)

D P (

Pa)

Pressure Drop Along the Other Branch Tube, Vapor Quality = 6%

Electrohydrodynamics Laboratory

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Pressure drop along EHD pump

15 kV 17 kV 18 kV 20 kV

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0 200 400 600 800 1000 1200 1400

Time (s)

D P (

Pa

)Pressure Drop Along EHD Conduction Pump

and Branch Tube, Vapor Quality = 20%

Electrohydrodynamics Laboratory

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0 200 400 600 800 1000 1200 1400Time (s)

D P (

Pa)

Pressure Drop Along the Other Branch Tube, Vapor Quality = 20%

Electrohydrodynamics Laboratory

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Pressure drop along EHD pump

15 kV 17 kV

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0 100 200 300 400 500 600 700

Time (s)

D P (

Pa

)Pressure Drop Along EHD Conduction Pump

and Branch Tube, Vapor Quality = 26%

Electrohydrodynamics Laboratory

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0 100 200 300 400 500 600 700Time (s)

D P (

Pa

)Pressure Drop Along the Other Branch

Tube, Vapor Quality = 26%

Electrohydrodynamics Laboratory

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Conclusions

Electrically driven flow generated by the EHD conduction pump successfully controlled the flow distribution between two parallel branch lines.

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Acknowledgement

American Society of Heating, Refrigerating and Air Conditioning Engineers.