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Abstract— Axial flow fans, while incapable of developing high pressures, they are well suitable for handling large volumes of air at
relatively low pressures. In general, they are low in cost and possessgood efficiency, and can have blades of airfoil shape. Axial flow fansshow good efficiencies, and can operate at high static pressures ifsuch operation is necessary. Our objective is to model and analyze
the flow through AXIAL FANS using CFD Software and drawinference from the obtained results, so as to get maximum efficiency.The performance of an axial fan was simulated using CFD and theeffect of variation of different parameters such as the blade number,noise level, velocity, temperature and pressure distribution on the
blade surface was studied. This paper aims to present a final 3D CAD
model of axial flow fan. Adapting this model to the availablecomponents in the market, the first optimization was done. After thisstep, CFX flow solver is used to do the necessary numerical analyses
on the aerodynamic performance of this model. This analysis resultsin a final optimization of the proposed 3D model which is presentedin this article.
Keywords — ANSYS CFX, Axial Fan, Computational FluidDynamics (CFD), Optimization.
I.I NTRODUCTION
HE axial flow fan is extensively used in many engineering
applications. This type of fan is used in a wide variety of
applications, ranging from small cooling fans for electronics tothe giant fans used in wind tunnels. Axial flow fans are
applied for air conditioning and industrial process
applications. Its adaptability has resulted in implementation
into large scale systems, from industrial dryers to automotive
engine cooling and in-cabin air recirculation systems [1], [2].
The extended use of axial flow fans for fluid movement and
heat transfer has resulted in detailed research into the
performance attributes of many designs. Numerical
investigations have been performed to quantify the
performance of axial fans and their flow characteristics [3].
Axial fans blow air along the axis of the fan, linearly, hence
their name. The axial-flow fans have blades that force air to
move parallel to the shaft about which the blades rotate [4].With the expressive computer capability and extensive
development in the simulation field, CFD have drawn
attention in recent years. With the help of CFD, the complex
3-D geometries of equipment can now be modeled with only
minor simplifications [5]. CFD models, if created correctly,
can account for the complex flows in equipment. CFD models
for axial fans have been used to evaluate the flow behavior
and characteristics. The models provide sufficiently accurate
predictions over a range of operating conditions, which are not
possible using other methods. In this paper, CFD was used to
Hemant Kumawat is a Mechanical Engineer, from VIT University,
Vellore, Tamil Nadu, India (2014) (phone: +917073195809; e-mail:[email protected]).
model the flow passing through an axial fan. The objective
was to determine ways to increase the efficiency.
Fig. 1 Axial fan assembly
Axial flow fans, while incapable of developing high
pressures, they are well suitable for handling large volumes of
air at relatively low pressures [6]. In general, they are low in
cost and possess good efficiency, and can have blades of
airfoil shape. The operating principle of axial-flow fans is
simply deflection of air. Flow can be decomposed into two
components: axial velocity and tangential or circumferential
velocity. Axial velocity is the desired velocity since it moves
air from/to the desired spaces and tangential velocity is an
energy loss in axial fans or it can be converted into static
pressure as in case of vane axial fans.
II. EXPERIMENTATION
The first step is to identify a typical axial flow fan that can
be reproduced as a 3-D CAD Solidworks® software
engineering drawing package (Fig. 2).
The 3-D models are then imported into the CFD software,
remodeled into different sections, and refined to generate a
finite volume meshing. This is a crucial step, where details of
the geometrical shape need to be defined precisely. The flow
domain is also created (Fig. 3), and the final meshing of all
components needs to be accurate. Any errors in the drawings
and flow area need to be corrected before continuing.
Modeling and Simulation of Axial Fan Using CFDHemant Kumawat
T
World Academy of Science, Engineering and Technology
International Journal of Mechanical, Aerospace, Industrial, Mechatronic and Manufacturing Engineering Vol:8, No:11, 2014
1899International Scholarly and Scientific Research & Innovation 8(11) 2014 scholar.waset.org/1999.8/10000214
I n t e r n a t i o n a l S c
i e n c e I n d e x ,
A e r o s p a c e a n d M e c h a n i c a l E n g i n
e e r i n g V o l : 8 ,
N o : 1 1 ,
2 0 1 4 w a s e t . o r g / P u b l i c a t i o n / 1 0 0 0 0 2 1 4
http://scholar.waset.org/1999.8/10000214http://scholar.waset.org/1999.8/10000214http://waset.org/publication/Modeling-and-Simulation-of-Axial-Fan-Using-CFD/10000214
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Fig. 2 Solidworks CAD model
Fig. 3 Computational domain
The second step is to import the files
preprocessor, which will solve the flow
flow fields boundary conditions are set. Tmass flow, outlet pressure, fluid properti
characterization, such as moving internal
solid walls. The next step is to set the si
3-D steady and turbulent problem (Fig. 4).
The simulation is preceded with the
the data, applying the basic theory of
balancing the mass continuity and mo
numerical form and thereafter pr
predictions of the flow variables. The pro
completed by defining the boundary
controls, and convergence monitors. Ass
ideal and dry air at standard atmosp
boundary conditions include fixed wall,
of fan
of fan
into the CFD code
equations. Here, the
hese include inlet aires, and flow domain
zone and stationary
ulation process as a
.
FD code processing
fluid mechanics by
entum equations in
oducing numerical
lem setup process is
conditions, solver
ming the flow to be
heric pressure, the
oving internal zone,
zero pressure at outlet, and
The residual values of all
during the iteration process.
monitored for convergence a
conditions are not satisfied.
output data and present tstreamline (Fig. 5) and conto
Fig. 4 Simul
Fig. 5 Velocit
III.
R ESULTS
On post-processing the
observations are present
temperature contour plots, a
Optimized design results
design for temperature cont
variable mass flow rate at inlet.
variables solved are monitored
his iteration process needs to be
d repeated if the numerical error
The final step is to analyze the
hem in the form of velocityr plots (Fig. 6).
ation parameters
streamline of fan
ND DISCUSSION
numerical CFD results, the
ed as velocity streamlines,
nd static pressure contour plots.
ere then compared with initial
our and velocity streamline and
World Academy of Science, Engineering and Technology
International Journal of Mechanical, Aerospace, Industrial, Mechatronic and Manufacturing Engineering Vol:8, No:11, 2014
1900International Scholarly and Scientific Research & Innovation 8(11) 2014 scholar.waset.org/1999.8/10000214
I n t e r n a t i o n a l S c
i e n c e I n d e x ,
A e r o s p a c e a n d M e c h a n i c a l E n g i n
e e r i n g V o l : 8 ,
N o : 1 1 ,
2 0 1 4 w a s e t . o r g / P u b l i c a t i o n / 1 0 0 0 0 2 1 4
http://scholar.waset.org/1999.8/10000214http://scholar.waset.org/1999.8/10000214http://waset.org/publication/Modeling-and-Simulation-of-Axial-Fan-Using-CFD/10000214
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presented in the form of contour plots.
separately for initial and optimized design
Fig. 6 Pressure contour of
A. Initial Design
Initially designed fan is having 7
designed fan, results were compiled for ai
22 m/s and having the outlet pressure as
shows the turbulence kinetic energy con
designed fan.
Fig. 7 Turbulence K.E. contour of initia
Fig. 8 shows the pressure contour of in
fan. By observing the pressure contour,
negative to positive scale; hence, creatin
the outlet.
Fig. 9 shows the temperature contour
axial fan. Variation in temperature occ
temperature of air and frictional h
variation is not uniform on the blade su
figure. Color (showing temp contour) is
Sudden change in temperature on the blad
the formation of thermal cracks which ca
Moreover, the airfoil design of the blade
esults are compiled
s.
an
lades. For initially
r flowing at a rate of
atmospheric. Fig. 7
tour plot of initially
lly designed fan
itially designed axial
ressure ranges from
g a pressure zone at
of initially designed
rs because of room
ating. Temperature
rface as seen in the
drastically changing.
e surface will lead to
n damage the blade.
gets distorted due to
the high temperature meltin
Temperature of the output
goes down.
Fig. 8 Pressure conto
Fig. 9 Temperature con
Fig. 10 Velocity stream
. Blade life is highly decreased.
air is also increased. Efficiency
r of initially designed fan
our of initially designed fan
line of initially designed fan
World Academy of Science, Engineering and Technology
International Journal of Mechanical, Aerospace, Industrial, Mechatronic and Manufacturing Engineering Vol:8, No:11, 2014
1901International Scholarly and Scientific Research & Innovation 8(11) 2014 scholar.waset.org/1999.8/10000214
I n t e r n a t i o n a l S c
i e n c e I n d e x ,
A e r o s p a c e a n d M e c h a n i c a l E n g i n
e e r i n g V o l : 8 ,
N o : 1 1 ,
2 0 1 4 w a s e t . o r g / P u b l i c a t i o n / 1 0 0 0 0 2 1 4
http://scholar.waset.org/1999.8/10000214http://scholar.waset.org/1999.8/10000214http://waset.org/publication/Modeling-and-Simulation-of-Axial-Fan-Using-CFD/10000214
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Fig. 10 shows the velocity streamlines
fan. By observing the plot, velocity
uniform over fan wheel which implie
uniform. Large variation in velocity ca
blade. As we can see from Fig. 10,
streamlines changes drastically as we moMoreover, there is a reduction in velocit
uniform flow will result in huge noise a
and will decrease the overall efficiency.
B. Optimized Design
Optimized designed fan is having 11 b
designed fan results were compiled
conditions as for the initially designed f
rate of 22 m/s and having the outlet pres
Fig. 8 illustrates the temperature co
designed fan.
Fig. 11 Temperature contour of optimiz
Fig. 11 shows the temperature co
designed axial fan. Variation in temperat
room temperature of air and frictional
variation is almost uniform on the blade s
same throughout the blade. This is evi
color pattern of temperature contour of
there is less chances of formation of
design of the fan blade remains uncha
working life of fan. Blade life is increaseoutput air is same or nearly same as i
increases.
Fig. 12 shows the velocity strea
designed fan. By observing the plot, vel
uniform which implies that flow is
variation in velocity across the blade is
streamlines is almost same across the bla
output. We get the desires output velocit
to the parameters given. As a result of u
lesser or negligible noise and all acoustic
and hence efficiency is increased.
of initially designed
streamlines are not
s that flow is not
be seen across the
the colour of the
ve across the blade.at outlet. This non
d acoustic problems
lades. For optimized
for same working
n - air flowing at a
sure as atmospheric.
tour of optimized
ed designed fan
tour of optimized
re occurs because of
eating. Temperature
urface or it is almost
dent form the same
lade. In this design
hermal cracks. The
ged throughout the
. Temperature of thenput air. Efficiency
lines of optimized
city streamlines are
uniform. Required
achieved. Color of
de, i.e., at input and
at output according
niform flow, we get
problems are solved
Fig. 12 Velocity streamli
IV.
CO
The results from the nu
insightful understanding of t
an axial fan with different
CFD analysis was performe
optimized designed axial fan
optimized design were then
axial fan. The key and impor
follows:
1) The CFD modeling sho
helpful in initiating fu
numerical study of the a
2)
CFD results were presstreamlines, which provi
air around the fan for dif
3)
The different parameter
noise, and turbulence,
performing CFD analysi
with an optimum numbe
compared to the fan wi
general, as a compromi
five to twelve blades a
optimized design is havi
ACKNO
The author thanks the ma
their support and permissio
expresses gratitude to all o
who contributed to the job d
of the operation to achieve th
R EF
[1]
S. Jain, and Y. Deshpande, “C
Air Flow Distribution,” in
and Technology, Vol : 6 2012-[2]
Mahajan Vandana N., ShekhAxial Flow Fan using Ansys,
Engineering Technology, E-IS
[3]
Prof. Jigar S. Patel Prof. Shai
Performance of Axial Fan Pe
ne of optimized designed fan
CLUSION
erical simulations provided an
e behavior of fluid flow around
umber of fan blades. Numerical
for both initially designed and
. The numerical CFD results for
compared with initially designed
ant outcomes of this study are as
n in this study proved to be very
rther and more comprehensive
ial fan.
ented in the form of velocityded actual flow characteristics of
ferent number of fan blades.
s like temperature, pressure, fan
were also considered while
s. The study revealed that a fan
r of fan blades performed well as
h less number of fan blades. In
se between efficiency and cost,
e good practical solutions. Our
g 11 blades.
LEDGEMENT
nagement of VIT University for
to publish this paper. He also
the faculties and lab assistants
esign, preparation, and execution
e results presented in this paper.
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orld Academy of Science, Engineering
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lesh M. Patel, “Parameter Affecting the
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World Academy of Science, Engineering and Technology
International Journal of Mechanical, Aerospace, Industrial, Mechatronic and Manufacturing Engineering Vol:8, No:11, 2014
1902International Scholarly and Scientific Research & Innovation 8(11) 2014 scholar.waset.org/1999.8/10000214
I n t e r n a t i o n a l S c
i e n c e I n d e x ,
A e r o s p a c e a n d M e c h a n i c a l E n g i n
e e r i n g V o l : 8 ,
N o : 1 1 ,
2 0 1 4 w a s e t . o r g / P u b l i c a t i o n / 1 0 0 0 0 2 1 4
http://scholar.waset.org/1999.8/10000214http://scholar.waset.org/1999.8/10000214http://waset.org/publication/Modeling-and-Simulation-of-Axial-Fan-Using-CFD/10000214
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[4]
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[6]
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World Academy of Science, Engineering and Technology
International Journal of Mechanical, Aerospace, Industrial, Mechatronic and Manufacturing Engineering Vol:8, No:11, 2014
1903International Scholarly and Scientific Research & Innovation 8(11) 2014 scholar.waset.org/1999.8/10000214
I n t e r n a t i o n a l S c
i e n c e I n d e x ,
A e r o s p a c e a n d M e c h a n i c a l E n g i n
e e r i n g V o l : 8 ,
N o : 1 1 ,
2 0 1 4 w a s e t . o r g / P u b l i c a t i o n / 1 0 0 0 0 2 1 4
http://scholar.waset.org/1999.8/10000214http://scholar.waset.org/1999.8/10000214http://waset.org/publication/Modeling-and-Simulation-of-Axial-Fan-Using-CFD/10000214