Group Title: 7th International Conference on Multiphase Flow - ICMF 2010 Proceedings
Title: P3.39 - Numerical Simulation of Gas-Liquid Wetted Wall Flows on an Inclined Plate
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 Material Information
Title: P3.39 - Numerical Simulation of Gas-Liquid Wetted Wall Flows on an Inclined Plate Experimental Methods for Multiphase Flows
Series Title: 7th International Conference on Multiphase Flow - ICMF 2010 Proceedings
Physical Description: Conference Papers
Creator: Iso, Y.
Chen, X.
Publisher: International Conference on Multiphase Flow (ICMF)
Publication Date: June 4, 2010
 Subjects
Subject: gas-liquid two-phase flow
wetted wall flow
film
rivulet
transition
packed column
texture
CFD
 Notes
Abstract: Gas-liquid two-phase flows on walls like liquid film flows, which are called as wetted wall flows, are observed in many industrial processes such as absorption, desorption, distillation and others. For the optimum design of packed columns widely used in those kind of processes, the accurate predictions of the details on the wetted wall flow behavior in packing elements are important, especially to enhance the mass transfer between the gas and liquid and to prevent flooding and channeling of the liquid flow. The present study focused on the effects of the change of liquid flow rate and the wall surface texture treatments on the characteristics of wetted wall flows which have the drastic flow transition between the film flow and rivulet flow. In this paper, the three-dimensional gas-liquid two-phase flow simulation by using the volume of fluid (VOF) model is applied into wetted wall flows. Firstly, as one of new interesting findings in this paper, present results showed that the hysteresis of the flow transition between the film flow and rivulet flow arose against the increasing or decreasing stages of the liquid flow rate. It was supposed that this transition phenomenon is depended on the history of flow pattern as the change of curvature of interphase surface which leads to the surface tension. Additionally, the applicability and accuracy of the present numerical simulation were validated by using the existing experiment studies with smooth wall surface. Secondary, referring to the texture geometry used in an industrial packing element, the present simulations showed that surface texture treatments added on the wall can improve the prevention of liquid channeling and can increase the wetted area.
General Note: The International Conference on Multiphase Flow (ICMF) first was held in Tsukuba, Japan in 1991 and the second ICMF took place in Kyoto, Japan in 1995. During this conference, it was decided to establish an International Governing Board which oversees the major aspects of the conference and makes decisions about future conference locations. Due to the great importance of the field, it was furthermore decided to hold the conference every three years successively in Asia including Australia, Europe including Africa, Russia and the Near East and America. Hence, ICMF 1998 was held in Lyon, France, ICMF 2001 in New Orleans, USA, ICMF 2004 in Yokohama, Japan, and ICMF 2007 in Leipzig, Germany. ICMF-2010 is devoted to all aspects of Multiphase Flow. Researchers from all over the world gathered in order to introduce their recent advances in the field and thereby promote the exchange of new ideas, results and techniques. The conference is a key event in Multiphase Flow and supports the advancement of science in this very important field. The major research topics relevant for the conference are as follows: Bio-Fluid Dynamics; Boiling; Bubbly Flows; Cavitation; Colloidal and Suspension Dynamics; Collision, Agglomeration and Breakup; Computational Techniques for Multiphase Flows; Droplet Flows; Environmental and Geophysical Flows; Experimental Methods for Multiphase Flows; Fluidized and Circulating Fluidized Beds; Fluid Structure Interactions; Granular Media; Industrial Applications; Instabilities; Interfacial Flows; Micro and Nano-Scale Multiphase Flows; Microgravity in Two-Phase Flow; Multiphase Flows with Heat and Mass Transfer; Non-Newtonian Multiphase Flows; Particle-Laden Flows; Particle, Bubble and Drop Dynamics; Reactive Multiphase Flows
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Resource Identifier: P339-Iso-ICMF2010.pdf

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Paper No 7th International Conference on Multiphase Flow
ICMF 2010, Tampa, FL USA, May 30-June 4, 2010






Numerical Simulation of Gas-Liquid Wetted Wall Flows on an Inclined Plate


Yoshiyuki Iso*l and Xi Chen*2

*1 : IHI INC., Business Development Division
150 East 52nd Street, 24th Floor, New York, NY 10022, USA
E-mail : yoshiyuki_iso~ihi.co.jp

*2 : Columbia University, Department of Earth and Environmental Engineering
500 West 120th Street, New York, NY 10027, USA
E-mail : xichen~columbia.edu


Keywords: gas-liquid two-phase flow, wetted wall flow, film, rivulet, transition, packed column, texture, CFD




Abstract

Gas-liquid two-phase flows on walls like liquid film flows, which are called as wetted wall flows, are observed in many
industrial processes such as absorption, desorption, distillation and others. For the optimum design of packed columns widely
used in those kind of processes, the accurate predictions of the details on the wetted wall flow behavior in packing elements
are important, especially to enhance the mass transfer between the gas and liquid and to prevent flooding and channeling of the
liquid flow.
The present study focused on the effects of the change of liquid flow rate and the wall surface texture treatments on the
characteristics of wetted wall flows which have the drastic flow transition between the film flow and rivulet flow. In this paper,
the three-dimensional gas-liquid two-phase flow simulation by using the volume of fluid (VOF) model is applied into wetted
wall flows. Firstly, as one of new interesting findings in this paper, present results showed that the hysteresis of the flow
transition between the film flow and rivulet flow arose against the increasing or decreasing stages of the liquid flow rate. It was
supposed that this transition phenomenon is depended on the history of flow pattern as the change of curvature of interphase
surface which leads to the surface tension. Additionally, the applicability and accuracy of the present numerical simulation
were validated by using the existing experiment studies with smooth wall surface. Secondary, referring to the texture geometry
used in an industrial packing element, the present simulations showed that surface texture treatments added on the wall can
improve the prevention of liquid channeling and can increase the wetted area.


1. Introduction

Gas-liquid two-phase flows on walls like liquid film flows,
which are called as wetted wall flows, are observed in many
industrial processes such as absorption, desorption,
distillation and others. Controlling these wetted wall flows
efficiently is one of the key design factors for such devices,
since they determine the process performances and limit of
the operations. For the optimum design of packed columns
widely used in those kind of processes, the accurate
predictions of the details on the wetted wall flow behavior
in packing elements are important, especially to enhance the
mass transfer between the gas and liquid phases and to
prevent flooding and channeling of the liquid flow.
As the fundamental researches, typical liquid falling film
flows have been often studied theoretically and
experimentally (Nusselt, 1916; Phan and Narain, 2007;
Wang, 2009). However, it is still not easy to apply these
results directly into the predictions in the specific industrial


packed columns, because it is difficult to use them
universally under the various conditions and it is risky to
use them beyond the range of their assumption.
On the other hand, several experimental studies have been
conducted for the specific packed columns in order to
improve the mass transfer performance and to develop
empirical modelings (Bravo et al., 1985 & 1995; Spiegel
and Meier, 2003; Murrieta et al., 2004; Sidi-Boumedine and
Raynal, 2005; Ataki et al., 2006; Chen et al., 2007; Raynal
et al., 2009). In most cases, however, these experimental
studies have been carried out by using air-water flows
instead of the actual fluids and by using smaller or simpler
experimental models than industrial ones. Thus, the fluid
properties effects and scale effects on the hydrodynamics
and mass transfer are not well known.
Recently, computational fluid dynamic (CFD) simulations
are useful as an alternative to experiments, because
multiphase flow measurements in the complex geometries
such as packing elements are very difficult and highly






7th International Conference on Multiphase Flow
ICMF 2010, Tampa, FL USA, May 30-June 4, 2010


Paper No


expensive, especially at the industrial large scale with actual
flow conditions. In the recent years, several studies can be
found in the literature, which deal with the CFD simulations
of gas-liquid two-phase flows in packed columns (Spiegel
and Meier, 2003; Valluri et al., 2005; Ataki et al., 2006;
Chen et al., 2007; Raynal et al., 2007 & 2009; Kenig, 2008;
Ludwig and Dziak, 2009). In these studies, two-dimensional
or three-dimensional CFD simulations have been used with
the volume of fluid (VOF) model, which is a surface
tracking technique in the Eulerian mesh. Several usable
results have been achieved such as the liquid thickness, hold
up, gas pressure drop, validation of CFD and so on.
Additionally, fewer studies exist on not only two-phase but
also three-phase film flows on an inclined wall (Hoffmann
et al., 2005 & 2006; Repke et al., 2007). Both the CFD and
experiment have been carried out to predict the liquid film
break-up, rivulet and droplet formation. Their interesting
studies have shown that this film break-up behavior has the
three-dimensionality and is strongly influenced by the
geometry.
Nevertheless, there is a lack of the literature data for the
detailed descriptions of the various difficulties of the
transition phenomena between the film flow and rivulet
flow and effects of wall surface texture treatments on this
kind of transition.
The present study focuses on the effects of the change of
liquid flow rate and the wall surface texture treatments on
the characteristics of wetted wall flows which have the
drastic flow transition between the film flow and rivulet
flow. Especially, this study investigates and discusses the
details of this flow transition by adding new findings such
as the hysteresis phenomena and those mechanisms, which
have not reported in existing literature. This study is
important in order to prevent the channeling and flooding of
liquid flow and to enhance the mass transfer performance.
In this paper, the three-dimensional gas-liquid two-phase
flow simulation by using VOF model is applied into wetted
wall flows. Firstly, the details of flow transition are
investigated by increasing and decreasing the liquid flow
rate. Additionally, the applicability and accuracy of the
present numerical simulation are validated by using the
existing experiment studies with smooth wall surface.
Secondary, the effects of wall surface texture treatments on
the prevention of liquid channeling and increase of wetted
area are investigated.


Nomenclature


width [m]
area [m2]
amplitude of the surface texture [m]


Greek letters
a inclined angle of the wall plate [degree]
P density [kgm-3]
pu viscosity [Pas]
a surface tension coefficient [Nm- ]
6 liquid film thickness [m]
/Z length of the surface texture [m]

Subsripts
1 liquid phase
g gas phase
m momentum
k phase k
f volume fraction
inertia
v viscosity
gr gravity
st surface tension
N Nusselt theory
w wetted surface
t total surface of the plate


2. Numerical Method

2.1 Computational region and flow conditions

As the outline of the present flow objects, the computational
region and a sample of grid for wetted wall flows are shown
in Figure 1. Additionally, Figure 2 shows two example
images of typical wetted wall flows which are the full film
flow and rivulet flow.
The geometry and flow conditions are set up in order to
validate present simulations by using the existing
experiment studies for the wetted wall flows on the inclined
wall plate (Hoffmann et al., 2005 & 2006; Repke et al.,
2007). The inclined wall plate is the 0.06 x 0.05 m2 stainless
steel plate, a flow field length of 0.06m and width of 0.05m,
which is held by supports on the left and on the right hand
side of same stainless steel. The inclined angle of the wall
plate a is 60 degree referring to the horizontal ground,
which is the inclination used commonly for the commercial
structured packing.
As the gas-hiquid two-phase fluids, the well known air-water
is used. The physical properties of gas and liquid
implemented in this simulation are referred to the existing
experiment (Hoffmann et al., 2006). As the physical
properties of gas, density p, is 1.185 kg/m3, VISCOSity
pg, is 1.831 x 105 Pa-s As the physical properties of
liquid, density pi is 997 kg/m3, VIScosity Ptl is
8.899 x 10-4 Pa -s surface tension coefficient ol is
0.0728 N/m. The static contact angle for air and water on
the stainless steel is applied 70 degree obtained by the
experimental measurement (Hoffmann et al., 2005 & 2006).
The liquid inlet condition is assumed as a uniform film flow
to consider the experimental liquid feeding conditions using


velocity [ms']
time [s]
static pressure [Pa]
gravitational acceleration [mS-2
source term, S,, [Nm-3] or S, [kgm-3S-1]
volume fraction [-]
force [N]
representative velocity [ms']
representative length [m]
Reynolds number [-]
Froude number [-]
Weber number [-]
volumetric flow rate [m3S-1]






7th International Conference on Multiphase Flow
ICMF 2010, Tampa, FL USA, May 30-June 4, 2010


Paper No


Inlet of liquid


Outlet Stainless walls

(a) Computational region


(b) Computational grid


Figure 1: The computational region and a sample of grid for wetted wall flows


Inlet of liquid


Inlet of liquid


Film flow


Film flow


Rivulets


4 Liquid film
3.0
20thickneSS
1.0 [mm]
0.0


4 Liquid film
3.0
thickness
1.0 [mm]
0.0


Outlet'
(a) Full film flow


Outlet '
(b) Rivulet flow (Channeling flow)


Figure 2: Two images of typical wetted wall flows in the present case (Birds-eye view)


an overflowing weir to make the formation of a stable film
flow. The plate and both side supports are implemented as
no-slip walls with given contact angles. The other
boundaries, which are upward, downward outlet and top
boundaries, are set to the pressure outlet conditions by using
defined static pressures.

2.2 CFD modeling for gas-liquid two-phase flows

In this study, CFD simulations are carried out with the
commercial code FLUENT, ANSYS Inc. The
three-dimensional and transient model for gas-liquid
two-phase flow simulations by a volume of fluid (VOF)
model are used to predict the wetted wall flows, because the
existing studies have shown that rivulet flows are influenced
strongly by three dimensional effects and therefore cannot
be predicted by analytical approaches and two-dimensional
CFD simulations (Hoffmann et al., 2005 & 2006, Ataki et
al., 2006, Repke et al., 2007).


The CFD models are based on the universal transport
equations of extensive magnitudes in differential volume of
the fluid. In case of hydrodynamics modeling, two
conservation equations of the mass and momentum are
solved numerically. The mass conservation leads to the
continuity equation, and the momentum conservation gives
the Navier-Stokes equation, as follows:

+ V (p v)= 0 (1)


C1 pp.CV,) _yp cV[. TV1'


+pg+Sm
where v and p are the velocity vector and static pressure of
the fluid, respectively. S,, is the source term vector
expressing the momentum sources such as the surface
tensions, the external forces and so on.
In this study, the set of these two equations is applied into






7th International Conference on Multiphase Flow
ICMF 2010, Tampa, FL USA, May 30-June 4, 2010


forces are defined as follows:

Fix pVl2Ll2 (4)
F7, pg ~VL, (5)

Fi.gr p, P)gLl3 (6)
Fist 1(7)
Normalizing the dominant forces by the inertia force, the
dimensionless groups can be obtained by the following:
F7, p;,VL, pu, 1
(8)
Fix PlV,2L,2 plVILI Rel



FI, tV7Ll2 ~ l2(9)
gL, 1
V,2 Fri
Fis 0 1
(10)
F,, plV,2L,2 plV12LI Wel
The dimensionless groups which characterize the present
liquid flow can be written by the above equations, namely:

Re, = Pt-V i(11)


Paper No


the single field shared among all phases, which is called the
shared-field approach, by using the Eulerian method. In this
case, turbulence is not taken into account since the range of
the Reynolds number of liquid flow indicates laminar.
Additionally, using the VOF model, the interphase surface
tracking technique is applied into the fixed Eulerian mesh.
The set of the above mass and momentum equations can be
accomplished with the relation describing the interphase
surface position. This relation is described by:

+V-Pkk k)=S 3)
dt +Vbk~ n=/ 3
where fk and vk are the volume fraction and velocity vector
of the phase k, respectively. Sf is the source term expressing
the mass sources such as the mass transfer between phases,
supplied mass and so on. In this case, Sf is zero on the
assumption that the mass transfer between gas and liquid
can be negligible.
In this VOF model, these volume fractions are assumed to
be continuous functions of space and time, and the sum of
volume fractions is equal to one. If fk =0, the calculation cell
is empty of the phase k. When fk =1, the calculation cell is
filled with the phase k. For 0< fk <1, the calculation cell
contains the interphase surface between the phase k and one
or more other phases.
As above mentioned, the set of the mass and momentum
equations, which is shared in the single field among the all
phases, is dependent on the volume fractions of all phases
through the fluid properties such as the density, viscosity
and so on.
The effects of surface tensions along the interface between
each pair of phases are implemented with the continuous
surface force (CSF) model proposed by Brackbill et al.
(1992). The surface tension can be considered in terms of
the pressure jump across the interphase surface. In this CSF
model, the addition of surface tension to the VOF model
results in a source term S,, in the momentum equation.
Additionally, in order to consider the effects of wall
adhesion, contact angles between the phases and the walls
are imposed as wall boundary condition. The wall adhesion
model proposed by Brackbill et al. (1992) is used. The
contact angles derived from static data are implemented by
setting the angle of the gradient of the volume fraction at the
wall boundary condition. The local curvature of the
interphase surface in the calculation cell next to the wall is
used to adjust the body force term in the surface tension
calculation.


3 Characterizations of wetted wall flows

3.1 Dominant forces on liquid flows

In this section, the dimensionless groups which characterize
the liquid flow are derived by considering the forces. In the
case of the present wetted wall flows, it is generally
accepted that the dominant forces on the liquid flow
characteristics are four forces: inertia force Fix viscous
force F7, gravitational force Figr and surface tension
Fist. Using the representative velocity VI and length Li
related to the outline system of this liquid flow, the above


Fr, = "
g-L,

We =P V -L


3.2 Definition of dimensionless groups

In this section, the dimensionless groups are redefined by
using the suitable representative quantities in order to apply
it into the present wetted wall flows. It starts to consider the
traditional expression of the falling film thickness
introduced by Nusselt (1916). This expression is the well
known Nusselt theory, in which the balance of only two
forces between gravitational force and friction force on a
fluid element in the film is considered by assuming the
steady continuous liquid film flow to be formed uniformly
on the plate. Using these classical works of Nusselt theory,
both falling film thickness and velocity distribution can be
calculated.
In the case of the falling liquid film flow on the inclined
plate, the liquid film thickness 6, is expressed as follows:

6,= 3l )g#ll-'1' (14)

where QI is the volumetric flow rate of liquid. w is width of
the liquid film on the plate, which is assumed to be equal to
the plate width as full film flow is developed completely on
the whole plate area in this case.
Usmng the hiquid film thickness 6, obtained by the Nusselt
theory, the above derived dimensionless groups are
redefined, which can be applied into the present wetted wall
flows, namely:
PI VI, '
Re, = (15)













































1.4 : Present resluts while increasing liquid flow rate

-n- : Present resluts while decreasing liquid flow rate

*: Experimental data by Hoffmann et al.


0.0 0.5 1.0 1.5 2.0 2.5

Weber number We IN [-]

Figure 3: The wetted areas A,/A, as a function of the Weber number Wel,


7th International Conference on Multiphase Flow
ICMF 2010, Tampa, FL USA, May 30-June 4, 2010



4. Results and Discussion

The present paper investigated and discussed the effects of
the change of liquid flow rate and the wall surface texture
treatments on the characteristics of wetted wall flows which
have the drastic flow transition between the film flow and
rivulet flow.

4.1 Wetted wall flows on the smooth surface

In this section, the effects of the change of liquid flow rate
on the flow transition of wetted wall flows on the smooth
surface are investigated. Additionally, the applicability and
accuracy of the present numerical simulation are validated
by using the existing experiment studies (Hoffmann et al.,
2005 & 2006, Repke et al., 2007).
Figure 3 shows that the wetted areas A, /A, obtained by
present simulations are plotted over the Weber number


Paper No


V 2
Frtw = tw(16)

PI -V1,2 .N
We gy=(17)

where V1N is the averaged liquid film velocity defined by
the following:

V, N= (1 8)

In this study, after-mentioned several present results are
explained relating to these dimensionless groups. Especially,
the Weber number Wel, is used for considering the
balance between inertia force and surface tension, which is
an important parameter for the flow transition phenomenon.


4.0 Liquid film
thickness
1.0 [mm]
0.0


Channeling flow

(b) Wel, =0.42


Channeling flow

(c) Wel, =0.80


Full film flow

(e) WelN=1.44


Channeling flow

(a) Wel, =0.04


(d) Wel, =1.05


Figure 4: The comparison of liquid flow patterns visualized by interphase surfaces between gas and liquid
(While the liquid flow rate is increasing)






7th International Conference on Multiphase Flow
ICMF 2010, Tampa, FL USA, May 30-June 4, 2010



4.2 Effects of wall surface texture treatments

It can be found that the several industrial packing elements
have the wall surface treatments such as small perforations
or texture in order to prevent the liquid channeling as the
film break-up and to increase the wetted area (Valluri et al.,
2005, Ataki et al., 2006, Raynal et al., 2007 & 2009). In this
section, the effects of wall surface texture treatments on the
flow transition of wetted wall flows are investigated.
Figure 5 shows the outline of the small surface texture on
the inclined wall used in the present simulation. The
amplitude a and length /Z of the surface texture are
selected referring to an industrial packing element (Raynal
et al., 2007 & 2009). In this case, the amplitude of the
surface texture is the same order as the liquid film thickness.
An example of results obtained the present simulations is
shown in Figure 6. These two results are simulated under
the same flow conditions. The channeling flow occurs in the
case of the smooth surface wall. The full film flow, however,
is kept on the whole plate in the case of the addition of
small texture on the wall surface. In this flow condition, the
wall surface texture treatments give the approximately 1.17
times larger wetted area than one on the smooth wall.
Thus, the present results show that surface texture
treatments added on the wall can improve the prevention of
liquid channeling and can increase the wetted area.


5. Conclusions

The present study was carried out to investigate the effects
of the change of liquid flow rate and the wall surface texture
treatments on the characteristics of wetted wall flows.
Firstly, present results showed that the hysteresis of flow
transition between the film flow and rivulet flow arose
against the increasing or decreasing stages of the liquid flow
rate which means the Weber number is changing. It should
be denoted that this transition phenomenon is depended on
the history of flow pattern as the change of curvature of
interphase surface which leads to the surface tension.
Additionally, the applicability and accuracy of the present
numerical simulation were validated by using the existing
experiment studies for the wetted wall flows on the smooth
surface.
Secondary, referring to the texture geometry used in an
industrial packing element, the present results show that
surface texture treatments added on the wall can improve
the prevention of liquid channeling and can increase the
wetted area.
As the results, present study showed that this numerical
simulation by using VOF model can be applied into not only
the investigation of wetted wall flow behavior such as film
break-up and rivulet flow but also the optimization of the
design of packmng elements.
In the future, a next step will be to investigate the effect of
wall surface texture more systematically. Furthermore,
another next step will be to investigate more complex
geometries and flow conditions such as industrial large scale
packing with actual flow conditions, and to develop a better
designing method for those two-phase flow processes.


Paper No


Wel, with the existing experimental data. Additionally,
the interphase surfaces between gas and liquid obtained by
the present simulations are shown in Figure 4. The
interphase surfaces between gas and liquid are visualized
using the iso-surfaces which are defined by the specific
volume fraction of liquid. As can be seen in Figure 4, two
types of flow patterns are observed mn this case. First type is
the full film flow, which means only film flow is formed on
the whole plate. Second type is the channeling flow, which
means both of the film flow and rivulet flows are formed on
the plate.
Firstly, as one of new interesting findings in this paper
which has not reported in existing literature, the present
results show that the transition patterns between the full film
flow and rivulet flow, where the wetted area changes
between Aw/A, =1 and less, are different significantly against
the increasing or decreasing stages of the Weber number.
Additionally, this difference of transition shows clearly that
there is the hysteresis phenomenon in the transition region.
While the liquid flow rate is increasing which means the
Weber number is increasing, the wetted area is increasing
continuously from the rivulet flow to the full film flow.
While the liquid flow rate is decreasing which means the
Weber number is decreasing, however, the wetted area
decreases suddenly from the full film flow to the rivulet
flow at the lower critical Weber number than one while the
liquid flow rate is increasing.
It is supposed that the main reason, why the above
hysteresis occurs, is the surface tension depended strongly
on the curvature of the interphase surface between gas and
liquid. When the film flow is formed continuously, the
curvature of the interphase surface is almost zero, and then
the surface tension on the liquid film surface is very low. On
the other hand, when the rivulet flows are formed once, the
surface tension forces strongly on the rivulet surface
because the rivulet has the curvature of the interphase
surface. Thus, it should be denoted that this flow transition
between the film flow and rivulet flow is depended on the
history of flow pattern as the change of curvature of
interphase surface which leads to the surface tension.
Here, the liquid flow rate is changed as step-like pattern not
continuously in this simulation. That means these simulation
results are obtained as the quasi-steady convergent solutions
by using the previous solution at the nearest liquid flow rate
as the initial condition. The hvsteresis pattern observed in
this paper might depend on the variation of the change of
liquid flow rate. This is another interesting point of this
study in the future.
Secondary, as the validation of the present simulation, the
critical range of the flow transition between the film flow
and rivulet flow can be accurately predicted by comparing
between the present simulation results and the experimental
results in Figure 3. Additionally, in terms of the liquid flow
shape, the present simulation results show very good
agreement qualitatively with the experimental photos
obtained by Hoffmann et al. (2006).
These validations show that the present two-phase flow
simulation by using VOF model is capable of predicting the
film break-up and rivulet flow on the inclined wall with
smooth surface.






7th International Conference on Multiphase Flow
ICMF 2010, Tampa, FL USA, May 30-June 4, 2010


Paper No


Inlet of liquid


2a =0.6mm



:.8mm


Gravity


Outlet Stainless walls

(a) Computational region with wall surface texture


(b) Details of the wall surface texture (Zoom of computational grid)


Figure 5: The computational region and a sample grid for wetted wall flows with wall surface texture treatments


erphase surface
ight from the
erence height
m]


(b) The result on the wall with surface texture ( Wel, =1.14)


Figure 6: The comparison of liquid flow patterns visualized by interphase surfaces between gas and liquid
(While the liquid flow rate is increasing)


Acknowledgements

The authors would like to appreciate gratefully the fruitful
conversation and support by our colleagues in the Professor
Chen's research group at the Columbia University.
Additional support was received from IHI Corporation.


References

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performance and pressure drop of structured packing: CFD
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534-543 (2006)

Ataki, A., and Bart, H. J., Experimental and CFD simulation
study for the wetting of structured packing element with
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Brackbill, J. U., Kothe, D. B. and Zemach, C., A continuum
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Bravo, J. L., Rocha, J. A. and Fair, J. R., Mass transfer in
gauze packing, Hydrocarbon Processing, 64, 1, pp. 91-95
(1985).

Bravo, J. L., Rocha, J. A. and Fair, J. R., A comprehensive
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Chen, J., Liu, C., Li, Y., Huang, Y., Yuan, X. and Yu, G.,
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Hoffmann, A., Ausner, I., Repke, J. U. and Wozny, G., Fluid


SInt
3.0 hej
2.0 ref
oM [m


(a) The result on the smooth surface wall ( Wel, =1.14)






Paper No 7th International Conference on Multiphase Flow
ICMF 2010, Tampa, FL USA, May 30-June 4, 2010



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