International Conference on Global Trends in Engineering, Technology and Management (ICGTETM-2016)
Computational Fluid Dynamics: Research Tool for Analysis
of Various Parts of Automotive Systems
V.S.Kathavate1* A.S.Adkine 2
1*
Department of Metallurgy and Materials Science, College of Engineering, Pune, 411005 (India)
Department of Mechanical Engineering, Shreeyash College of Engineering and Technology, Aurangabad,
431005 (India)
2
ABSTRACT- This current article accounts for the
analysis of engine mounting bracket by using
Computational fluid dynamics technique. ANSYS
software was used for the analysis purpose and
results are so obtained pertaining to the optimized
level. This paper gives the little idea about the new
modern techniques used in the CFD and view
progress that has been made the over the distance
revolution in the field of engineering with the
reinforcement of new modern technologies recently
developed. It so addresses the scientist, engineers
and mathematician who are willing to deal with the
field of computational fluid dynamics. The results
were analyzed for stresses and deformations. The
design was tested for different materials like
Aluminium, ERW-1 and ERW-2 along with
suitability of material.
flow, as governed by the NEVIER-STOKES
equation was performed at Los Alamos National
Labs[10]. Meanwhile in two dimensional (2-D)
real, a number of panel codes have been developed
for an airfoil analysis and design. The codes were
typically dealt with boundary layer analysis and so
that which would results in elimination of viscous
effect[10,12].Currently, its main application is as
an engineering method, to provide data that is
complementary to theoretical and experimental
data. This is mainly the domain of commercially
available codes and in-house codes at large
companies[11,12]. Some fundamentals of CFD are
(figure 1);
Key words: CFD–Computational fluid dynamics,
Discretization, FEM – Finite element method,
Grid, ERW-1, ERW-2, ANSYS.
I.
INTRODUCTION
Computational fluid dynamics generally
known as CFD is the progressive research tool for
analysis and evaluation for various types of
mechanical parts designed by the mechanical
industries or automobile sector. The main purpose
of the CFD, using as the research tool is that to
impart a forum for the cross fertilization of the
ideas, tools, techniques and with the imposement of
aeronautical science, geophysics and environmental
science[1-2]. This is applicable for all the
disciplines where fluid flow is taken into an
account.
Being
the best designer one should able to design the
product with maximum efficiency, more comfort
ability that would meet the various requirements of
customers with the phenomenon of optimum
cost[3]. It is very important that to realize the
functional requirement and appearance of the
existing product. In many cases the functional
requirements results in various types of shapes and
sizes
which
has
aesthetically
pleasant
appearance[4]. For ex.: The evaluation of the
streamline shaped Boeing is results in the studies of
Aerodynamics for the precision and effortless
speed.
The first work using computer model
ISSN: 2231-5381
Fig.1 Basic concepts of CFD
A. STAGES OF CFD:
1) During Initial Stage of Processing:
a] The geometry (physical bounds) of the problem
defined.
b] The volume occupied by the fluid is divided into
the small discrete cells (mesh).
c] Physical modeling in terms of all the parameters
(i.e. kinematic, thermodynamic, heat transfer etc.)
(Motion equation+ enthalpy + radiation + species
conversion).
2) Processing Stage:
a] Boundary conditions are defined involving
specified fluid behaviour and properties of
boundaries of the problem are defined.
b] The simulation is started and the equations are
http://www.ijettjournal.org
Page 344
International Conference on Global Trends in Engineering, Technology and Management (ICGTETM-2016)
solved iteratively as steady state or the transient
state.
3) Post Processing: Finally, the analysis is done and
visualization for resulting solution.
4) Pre-screening and Preparation: After identifying
the list of problems and recognizing them, they
must be screened and put them into the decreasing
order of profit and increasing order of investment
as well as difficulty of breaking technology. This
process is carried out to collect technical data,
maintenance data and Performance specifications.
Technical data helps to generate in the stages
including dimensions of parts to be analyzed,
surface
finish interfaces,
tolerances
and
performance and testing quality assurance
requirements. However engineering drawings of
the models are prepared for the prototypes and
drafted with the help of different software exiting
in CAD (i.e. COMPUTER AIDED DESIGN).
5) Numerical Simulation:
a] System-level CFD problems (Includes all
components in the product)
b] Component or detail-level problems (Identifies
the issues in a specific component or a subcomponent)
c] Different
tools for the level of analysis Coupled physics
(fluid-structure interactions).
B.
GENERAL
FACTS
ABOUT
DISCRETIZATION:
Discretization in space
produces a system of ordinary differential equation
for unsteady state problems and algebraic equation
for steady state problems. Implicit or semi implicit
methods are generally used for integrating the
ordinary differential equations which leads to
produce a system usually non linear equation[14].
So by applying NEWTON and PICARD’S
iteration, which will then produces a system of
linear algebraic equation which is non symmetric in
the presence of advection and indefinite in the
presence of the incompressibility[1].
C. METHOD OF DISCRETIZATION:
Domain is discretized into a finite set of
control volumes or cells. The discretized domain is
called the “grid” or the “mesh.”
ISSN: 2231-5381
t
•
General conservation (transport) equations
for mass, momentum, energy, etc., are
discretized into algebraic equations.
•
All equations are solved to render flow
field.
dV
V
V dA
A
dA
A
S dV
V
Table 1 Terms used in equation
Eqn.
continuity
x-mom.
y-mom.
energy
1
u
v
h
D. GRID GENERATION SOFTWARE:
There are in numerous methods
available for generation of mesh. But most
convenient method is by using Finite Element
Method (FEM). In mathematics Finite Element
Method (FEM) is numeric technique for finding
approximate solution to boundary condition
problem. It uses variation method (the calculus of
variation) to minimize the error function and to
produce stable solution. Variety
of
specializations under the umbrella of the
mechanical engineering discipline (such as
aeronautical, biomechanical, and automotive
industries) commonly use integrated FEM in design
and development of their products[13].
Several modern FEM
packages include specific components such as
thermal, electromagnetic, fluid, and structural
working environments. In a structural simulation,
FEM helps tremendously in producing stiffness and
strength visualizations and also in minimizing
weight, materials, and costs.
FEM
allows
detailed
visualization of where structures bend or twist, and
indicates the distribution of stresses and
displacements. FEM software provides a wide
range of simulation options for controlling the
complexity of both modeling and analysis of a
system. FEM allows entire designs to be
constructed, refined, and optimized before the
design is manufactured.
http://www.ijettjournal.org
Page 345
International Conference on Global Trends in Engineering, Technology and Management (ICGTETM-2016)
Fig.2 Procedure of CFD analysis
II. ENGINE MOUNTING BRACKET
In an automotive vehicle, the engine rests
on brackets which are connected to the main-frame
or the skeleton of the car. Hence, during its
operation, the undesired vibrations generated by the
engine and road roughness can get directly
transmitted to the frame through the brackets[15].
This may cause discomfort to the passenger(s) or
might even damage the chassis. When the operating
frequency or disturbance approaches the natural
frequency of a body, the amplitude of Vibrations
gets magnified.
The need for light weight
structural materials in automotive applications is
increasing as the pressure for improvement in
emissions and fuel economy increases. The most
effective way of increasing automobile mileage
while decreasing emissions is to reduce vehicle
weight[1,16]. The noise and vibration occur
because the power that is delivered through bumpy
roads, the engine, and suspension result in the
resonance effect in a broad frequency band. The
ride and noise characteristics of a vehicle are
significantly affected by vibration transferred to the
body through the chassis mounting points from the
engine and suspension[1].
There are two major problems that
engineers must deal with when it comes to
vibration isolation. The first problem is force
isolation, which is frequently encountered in
rotating or reciprocating machinery with
unbalanced masses. The main objective in this
problem is to minimize the force transmitted from
the machine to the supporting foundation. The
second problem is motion isolation. The natural
frequency of the mounting system should be lower
than the engine disturbance frequency to avoid the
excitation of the mounting system resonance. This
will ensure a low transmissibility
ISSN: 2231-5381
Fig 3: Isometric view of the mounting bracket
III. EXPERIMENT
A. Static Structural Analysis of Engine
Mounting:
Static Analysis deals with the conditions
of the equilibrium of the bodies acted upon by
forces. A Static analysis is used to determine the
displacements, stresses, strains and forces in
structures and components caused by loads that do
not induce significant inertia and damping effects.
The kind of loading that can be applied in static
analysis includes External applied forces, pressures
and moments Steady state inertial forces such as
gravity
and
spinning
imposed
non-zero
displacements.
Fig 4: Flow chart for Static Structural analysis
B. Alternative Material for Engine Mounting
Bracket:
a] ALUMINUM: Aluminum has only about one
third the density of steel and the most commercial
aluminum alloys posses substantially higher
specific strength than steel. A vehicle weight
reduction would not only result in higher oil
savings, but also gives a significant reduction in
emission. For these reasons there is preference to
use more aluminium and replace steel in
automotive applications. Aluminium alloy under
consideration has following material properties:
Young’s modulus – 6.9× 109 N/m2
Poisson’s ratio – 0.33
Density – 2770 Kg/m3
Yield strength in tension & compression
– 95×106 N/m2.
http://www.ijettjournal.org
Page 346
International Conference on Global Trends in Engineering, Technology and Management (ICGTETM-2016)
b] ERW-1: Electric resistance welded or high
frequency induction welded steel tubes designated
as ERW. It comprises of 0.12%C, 0.60%Mn,
0.04%S and 0.04%P. This ERW-1 steel contains
following mechanical properties (Table-2);
Table-2 Mechanical Properties of ERW-1
Designation
ERW-1
Tensile
Strength
(MPa)
310
Yield
Strength
(MPa)
160
% Elongation
on (Gauge
length )
20
c] ERW-2: This ERW-2 steel contains 0.25%C,
1.20%Mn, 0.04%S and 0.04%P. It possesses
following mechanical properties (Table-3);
Table 5 Maximum displacement ERW1 v/s Aluminum v/s
ERW2
Maximum
displacement
First Mode
ERW-1
(mm)
29.19
Aluminum
(mm)
29.18
ERW-2
(mm)
25.60
Second Mode
31.13
31.117
27.89
Third Mode
33.22
33.26
30.10
Fourth Mode
34.84
34.82
31.15
Fifth Mode
47.38
47.38
38.83
Sixth Mode
35.51
35.49
31.90
Tensile
Strength
(MPa)
Yield
Strength
(MPa)
ERW-2
380
240
%
Elongation
on (Gauge
length )
15
IV. RESULTS AND DISSCUSSION
A. Modal Analysis: Modal analysis was done for
obtaining the different frequencies for Aluminum,
ERW-1, and ERW-2 materials (Table 4);
Table 4: Frequency ERW-1 v/s Aluminum v/s ERW-2
Frequency
1
2
3
4
5
6
ERW-1
(Hz)
68.897
87.596
106.05
195.83
266.74
520.41
Aluminum
(Hz)
68.796
87.407
106.05
195.79
266.69
520.28
ERW-2
(Hz)
52.56
68.409
85.234
160.652
221
448.324
As the mode of frequency was changed, initially no
change was observed in ERW-1 and Aluminum
material. But ERW-2 shows large variation in
frequency as compared to ERW-1 and Aluminum.
This is probably due to the varying composition
and superior mechanical properties of ERW-2
material(figure 5).
Frequency (Hz)
600
ERW-2
Aluminum
ERW-1
MODES
Fig.6 Maximum displacement ERW-1 v/s ERW-2
The convergence of frequencies for ERW-2
material is good. The first excitation frequency
value for ERW-2 is higher than that of excitation
frequency range of engine. The values of
frequencies are nearly same for ERW-1 and
aluminum bracket.
B. Alternative Material for Engine Mounting
Bracket:
ANSYS software was used for stress analysis and
results are tabulated in Table-5;
Table 6: Stress Distribution among ERW-2, Aluminum and
ERW-1
500
400
ERW- 2
Aluminum
alloy
ERW-1
82.96
64.588
68.87
1.086
3.88
1.90
ERW-1
300
Aluminum
200
ERW-3
100
0
45
35
25
15
5
First Mode
Second…
Third Mode
Fourth…
Fifth Mode
Sixth Mode
Designation
DISPLACEMENT IN mm
Table-3 Mechanical Properties of ERW-2
Mode of Frequency
Von-Mises
stress(max)
(MPa)
Total
deformation
(mm)
Fig.5 Frequency ERW-1 v/s Aluminum v/s ERW-2
ISSN: 2231-5381
http://www.ijettjournal.org
Page 347
International Conference on Global Trends in Engineering, Technology and Management (ICGTETM-2016)
[3] W. Anderson, R. Rausch, D. Bonhaus, “Implicit multigrid
algorithms for incompressible turbulent flows on unstructured
grids”, (1996) J. Comput. Phys. Vol.128 pp 391–408.
STRESS AND
DEFORMATION
350
250
150
ERW-1
50
ALUMINUM
-50
ERW-2
-150
Fig.7 Comparison between ERW-2, Aluminum and ERW-1
It can be anticipated that ERW-2 is the best
material for the desired application.
[4] M.J.H. Anthonissen, B. van’t Hof, A.A. Reusken, “A fnite
volume scheme for solving elliptic boundary value problems on
composite grids”, Computing Vol.61 pp 285–305.
[5] S R Shaha, S V Jain, R N Patel, V J Lakhera, “CFD-for
pump: a review of state-of-the-art” (2013) Procedia Engineering
Vol. 51 pp 715 – 720.
[6] Usha, P.Syamsundar, “Computational analysis on
performance of a centrifugal pump impeller”, (2010)
Proceedings of the 37th National & 4th International Conference
on Fluid Mechanics and Fluid Power. Chennai, India, paper
TM-07.
[7] Yasushi Ito “Challenges in unstructured mesh generation for
practical and efficient computational fluid dynamics
simulations”, (2013) Computers & Fluids Vol.85 pp 47–52.
[8] P.Wesseling, Principles of Computational fluid dynamics,
Springer link (2001).
V. CONCLUSIONS
[9] John W. Slater, CFD analysis NASA OFFICIAL, Tuesday
17,2008, www.grc.nasa.gov.in
Computational Fluid Dynamics is a
powerful way of modeling fluid flow, heat
transfer, and related processes for a wide
range of important scientific and
engineering problems.
A fully integrated numerical method for
flutter analysis with a coupled fluidstructure interaction is presented.
The technique replaces a hands-on process
guided by experience to yield accurate and
reliable low fidelity models.
The Computational fluid dynamics tool,
ANSYS has been used to analyze the
engine mounting bracket. The results
obtained from the static structural and
modal analysis shows that ERW-2 steel is
better than ERW-1 steel. From the results
it can be said that the ERW-2 steel bracket
is safe for the required application.
This work also contributes to the defining
alternative material engine mounting
bracket, in which aluminum alloy were
studied along with ERW-1 and ERW- 2
steel. After analyzing the results, it can be
anticipated that ERW-2 can be proffered
over Aluminum and ERW-1.
Stiffness of ERW-2 found better than
Aluminum, so it may be used for required
application of engine mounting bracket.
[10] ZHANG Baoqiang, CHEN Guoping a, GUO Qintao,
“Static Frame Model Validation with Small Samples Solution
Using Improved Kernel Density Estimation and Confidence
Level Method” (2012) Chinese Journal of Aeronautics, vol. 25
pp 879-886.
[11] ZHANG Man, FU Zhenbo, LIN Yuzhen, LI Jibao“CFD
Study of NOxEmissions in a Model Commercial Aircraft Engine
Combustor” (2012), Chinese Journal of Aeronautics vol. 25 pp
854-863.
[12]Gareth A. Taylor b, Michael Hughes, Nadia Strusevich,
KoulisPericleous“Finite volume methods applied to the
computational modelling of welding phenomena” (2002)
Applied Mathematical Modelling vol.26 pp 309–320.
[13] Slawomir Kozieland, Leifur Leifsson, “Multi-level CFDbased Airfoil Shape Optimization with Automated Low-fidelity
Model Selection” (2013) Procedia Computer Science vol.18 pp
889 –898.
[14] ZHENG Yun, YANG Hui, “Coupled Fluid-structure
Flutter Analysis of a Transonic Fan” (2011) Chinese Journal of
Aeronautics vol.24 pp 258-264.
[15] Jasvir Singh Dhillon, Priyanka Rao, V.P. Sawant “Design
of Engine Mount Bracket for a FSAE Car Using Finite Element
Analysis” (September 2014) Int. Journal of Engineering
Research and Applications ISSN : 2248-9622, Vol. 4, Issue 9
(Version 6), , pp.74-81.
[16] Kichang Kim and Inho Choi, “Design Optimization
Analysis”, SAE TECHNICAL,2003-01-1604.
REFERENCES
[1] A.S.Adkine, V.S.Kathavate, G.P.Overikar, S.N.Doijode,
“Static Behaviour of Engine Mounting Bracket” (April 2015)
International Advanced Research Journal in Science,
Engineering and Technology Vol. 2, Issue 4, pp 68-73.
[2] P. Wesselinga;, C.W. Oosterleeb, “Geometric multigrid with
applications to computational fuid Dynamics” (2001) Journal of
Computational and Applied Mathematics Vol.128 pp 311–334.
ISSN: 2231-5381
http://www.ijettjournal.org
Page 348
International Conference on Global Trends in Engineering, Technology and Management (ICGTETM-2016)
AUTHOR’S AUTOBIOGRAPHY:
V.S.Kathavate is the M.Tech. research student
studying in College Of Engineering, Pune 05. He
has done his UG in Mechanical Engineering with
honours in First Division with Distinction from
Hitech Institute of Technology, Aurangabad. His
main interest lies in Heat and Mass Transfer, Micro
Machining
Process,
Computational
Fluid
Dynamics, and Boundary Layer Thickness. Besides
That Corrosion and its Protection is also his area of
research. During his UG he has done the major
research work on An Experimental Investigation of
Micromilling. This article was published in
Internatio nal
Journal
of
Technology
Enhancements and Emer ging Engineering
Research (ISSN 2 347-4289) for April 2015
issue. He has also attended the various
National level Conferences on Mechanical
Engineering,
Materials
Science
and
furnished the var ious papers and articles
in them. The article Static Behaviour of Engine
Mounting Bracket published in International
Advanced Research Journal on Science,
Engineering and Technology for April, 2015 issue
was also co-authored by him.
ISSN: 2231-5381
A.S.Adkine is the Assistant Professor in
Shreeyash College of Engineering and Technology,
Aurangabad. His main enthu stands in the subjects
like Theory of Machines, Mechanical Drawing and
Management related subjects. During his career he
is very well known and versatile personality among
his subordinates and his student. Currently his
ongoing research is on static and dynamic
behaviour of engine mounting bracket. He has his
publication on Static Behaviour of Engine
Mounting Bracket. This article was published in
International Advanced Research Journal on
Science, Engineering and Technology for April,
2015 issue. Prof. Adkine had attended and
conducted the vario us workshops and
sessions on various subjects like Vibratio n
analysis, ANSYS so ftware tools, Rapid
prototyping, and vario us Manufacturing
process.
http://www.ijettjournal.org
Page 349