Experimental investigation of the role of interfacial area in

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15 Νοε 2013 (πριν από 3 χρόνια και 8 μήνες)

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Experimental investigation of the role of interfacial area in
two
-
phase flow models using glass etched micro
-
models


N.K. Karadimitriou, S.M. Hassanizadeh and P. J. Kleingeld.

Utrecht University, Earth Sciences Department, Faculty of Geosciences.

Budapestlaan

4, 3584 CD, Utrecht, The Netherlands.

Introduction

In

order

to

investigate

the

significance

of

incorporating

interfacial

area

as

a

separate

variable

in

the

governing

equations

of

two
-
phase

flow,

an

experimental

setup

to

study

and

visualize

two
-
phase

flow

in

a

micro
-
model

under

dynamic

conditions

is

constructed
.

In

this

setup,

a

combination

of

lenses,

three

beam

splitters

and

four

cameras

are

used

to

visualize

flow

in

a

two
-
dimensional

micro
-
model
.

Four

micro
-
models

will

be

made

with

different

number

of

pore

bodies

and

mean

pore

size
.

The

total

size

of

the

flow

network

will

be

5
mm

x

35

mm
.

The

pore

network

will

be

etched

into

glass

plates
.

Through

image

analysis,

both

average

saturation

and

average

specific

interfacial

area

can

be

d
etermined
.

In

our

case,

with

the

use

of

four

cameras,

an

area

of

5

x

30

mm
2

can

be

visualized

at

a

resolution

of

3
.
0

μ
m

per

pixel,

at

any

given

instant
.

Thus

the

evolution

of

saturation

and

interfacial

area

in

time

and

space

will

be

determined
.


Objective of the experiment


The
investigation of the validity of a fundamental theory that includes interfacial area in order to improve our ability to
predict two
-
phase
flow and transport in porous media
.


1 2
( )
wn
k K
q P g S

    


   

        
(,)
wn
n w c w
P P P S

 
where and are material

coefficients and is the


specific interfacial area of


the
wn
-

interface.

1


2


wn

Experimental Setup

Computer

Camera

Beam splitters

Camera

Lens

Camera

Camera

Micro
-
model

Illumination

Introduction of fluids

Micro
-
models
:

Four

different

configurations

will

be

used

with

different

number

of

pore

bodies

and

different

mean

pore

sizes

with

the

same

overall

size

of

5

mm

x

35

mm
.


These

are
:



2000

pore

bodies,

6000

pore

throats,

mean

pore

size

of

40

μ
m



3000

pore

bodies,

9000

pore

throats,

mean

pore

size

of

μ
m



3000

pore

bodies,

9000

pore

throats,

mean

pore

size

of

70

μ
m



6000

pore

bodies,

19000

pore

throats,

mean

pore

size

of

50

μ
m
.

The

flow

network

has

been

designed

based

on

Delaunay

triangulation
.

It

will

be

etched

on

a

glass

substrate

using

D
eep

R
eactive
-
I
on

E
tching
.




Illumination
:

The

illumination

source

that

is

going

to

be

used

is

an

LED

collimated

light

source

emitting

at

a

frequency

of

560

nm
.

Its

working

distance,

meaning

the

distance

up

to

which

collimation

is

higher

than

80
%
,

is

400

mm
.

Lens(
es
)
:

A

series

of

lenses

will

be

used

in

order

to

reach

the

wanted

resolution

of

3
.
0

μ
m/pixel
.

Beam

splitters
:

Three

beam

splitters

will

be

used

in

order

to

create

four

identical

images

from

a

single

network
.

Cameras
:

Four

high

resolution

CCD

cameras

will

be

used

in

order

to

capture

images

from

four

consecutive

parts

of

the

flow

network

at

a

resolution

of

3
.
0

μ
m

per

pixel
.

Introduction

of

fluids
:

A

computer
-
based

differential

pressure

controller

will

introduce

the

fluids

and

measure

the

differential

pressure

at

the

boundaries

of

the

model
.

Computer
:

A

computer

will

be

used

in

order

to

control

the

cameras

and

record

images
.

The

differential

pressure

controller

will

also

be

connected

to

this

computer
.

This

will

make

sure

that

the

pressure

measurements

and

the

images

taken,

will

have

the

same

time

reference
.

Measurement

of

flow
:

With

the

use

of

a

small

capillary,

flow

will

also

be

measured
.

The

displacement

of

a

bubble

in

the

capillary,

given

the

geometric

properties

of

the

capillary,

will

make

the

measurement

of

flow

possible
.

The

use

of

a

flow
-
meter

is

also

being

considered
.








Experimental procedure

Initially

the

micro
-
model

will

be

fully

saturated

with

the

wetting

phase

(water)
.

The

non
-
wetting

phase

(
fluorinert
)

will

be

introduced

by

increasing

the

pressure

in

the

non
-
wetting

phase

reservoir
.

As

soon

as

the

non
-
wetting

phase

breaks

through

the

flow

network,

pressure

will

be

lowered

so

that

the

system

will

start

to

imbibe
.

During

drainage

and

imbibition,

pictures

will

be

taken

by

the

four

cameras
.

The

beam

splitters

will

make

this

possible

since

they

will

produce

four

identical

images

of

the

flow

network,

at

a

magnification

factor

of

unity
.

Each

camera

will

focus

on

a

different

area

of

the

flow

network

and

will

monitor

an

area

of

5

mm

x

7
.
6

mm

at

a

resolution

of

3
.
0

μ
m/pixel
.

In

total,

an

area

of

5

mm

x

30

mm

will

be

monitored

at

all

times
.

The

images

acquired

from

the

cameras

are

guided

to

the

computer

through

ethernet

cables

at

a

rate

of

75

Mbytes

per

second,

per

camera
.

At

the

same

time,

the

pressure

difference

between

the

inlet

and

the

outlet

of

the

micro
-
model,

as

well

as

flow,

will

be

recorded

and

stored

in

a

log

file
.



Data Processing

The

images

acquired

from

the

flow

network

during

drainage

and

imbibition

will

be

processed

using

image

processing

software
.

Phase

saturation

and

interfacial

area

will

be

determined

at

any

given

instant
.

Given

the

fact

that

differential

pressure

between

wetting

and

non
-
wetting

phase,

and

flow,

will

also

be

measured

at

the

same

timeframe,

the

substitution

of

the

experimental

results

in

the

two
-
phase

flow

equations

will

verify

the

validity

of

the

extended

theories

by

creating

a

unique

(
Pc,S,a
)

surface

for

drainage

and

imbibition
.

Images

taken

from

the

mask

produced

based

on

the

2000

pores

network
.


The

resolution

of

the

mask

is

0
.
6

μ
m

per

pixel
.