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HEAT TRANSFER SIMULATION FROM
FINS OF AN AIR-COOLED ENGINE BY USING CFD
A PROJECT REPORT
Submitted by
ARAVIND.B 12008114006
DASAN SISIL RAJ.G 12008114021
DINESH.R 12008114024
SURESH KUMAR.K 12008114101
In partial fulfilment for the award of the degree
Of
BACHELOR OF ENGINEERING
IN
MECHANICAL ENGINEERING
VELAMMAL ENGINEERING COLLEGE, CHENNAI
ANNA UNIVERSITY: CHENNAI – 600 025
APRIL 2012
ANNA UNIVERSITY: CHENNAI 600 025
BONAFIDE CERTIFICATE
Certified that this project report “Heat Transfer Simulation from Fins of an
Air-cooled Engine by Using CFD” is the bonafide work of “Aravind.B,
Dinesh.R, Dasan Sisil Raj.G, Suresh Kumar.K” who carried out the project
work under my supervision.
SIGNATURE SIGNATURE
Dr. M. Balasubramanian Mr. M. Karthick
HEAD OF THE DEPARTMENT SUPERVISOR
Department of Mechanical Engineering Assistant Professor
Velammal Engineering College Department of Mechanical Engineering
Velammal Engineering College
CERTIFICATE OF EVALUATION
College Code and Name : 120, Velammal Engineering College, Chennai.
Branch & Semester : Mechanical Engineering / VIII Semester.
S.
NO
NAME OF THE
STUDENTS
REG
NUMBER TITLE OF PROJECT
1 ARAVIND.B
12008114006 HEAT TRANSFER
SIMULATION BY
CFD FROM FINS OF
AN AIR-COOLED
ENGINE
2 DASAN SISIL RAJ.G
12008114021
3 DINESH.R
12008114024
4 SURESH KUMAR.K 12008114101
The report of the project work submitted by the above students in partial
fulfilment for the award of Bachelor of Engineering Degree in MECHANICAL
ENGINEERING of Anna University, Chennai was evaluated and confirmed to
be the report of work done by above students and then evaluated
INTERNAL EXAMINER EXTERNAL EXAMINER
ACKNOWLEDGEMENT
We express our sincere thanks to Shri. M.V. Muthuramalingam, Chairman,
Mr. M.V.M. Velmurugan, CEO, Dr.R.S. Kumar, Principal and
Dr.G.Prabhakaran, Vice-Principal of Velammal Engineering College for
their support and creating a comfortable atmosphere required for this project.
We are very much grateful to Dr.M. Balasubramanian, Professor and Head
of Department of Mechanical Engineering, Velammal Engineering College
for his encouraging support and useful suggestions during this work.
We express our profound sense of gratitude to Mr. M. Karthick, Assistant
Professor, Department of Mechanical Engineering, Velammal Engineering
College for his excellent guidance, help and constant encouragement throughout
the project work as our project guide.
We take this opportunity to thank all teaching members of our department for
their suggestion and help. We also thank all non-teaching staff for their co-
operation and help during this project work.
Last but not the least; we thank our parents who have been the source of
inspiration and support for us throughout this project work. We also thank all
those who have either directly or indirectly helped during this project work.
ABSTRACT
The main objective of this project is to analyze the various
cross-sections of fins which are currently being used in air cooled engines
for heat transfer by using CFD.Initially various details about the current
trends in engine designing were studied. The various dimensions of all the
components of the engine are measured using standard measurement tools
such as Vernier callipers, metre scale, etc. Various preliminary designs were
obtained which were then subjected to different analysis and finally a
modified design will thus be arrived.
The various parameters taken into consideration for optimization are
✓ Heat transfer rate
✓ Air Flow & Resistance Offered To Flow
✓ Surface Area
✓ Weight of the component
✓ Cost
The proposed design of the fin is considered to be far more effective and
efficient than the existing design. It also involves least amount of material
among all different alternatives and hence it requires less cost for production.
This project aims to achieve an optimized design for engine fins.
CONTENTS
Chapter no. Title Page no.
List of Figures
List of Tables
List of Symbols & Notations
i
ii
iii
1. Introduction
1.1 About IC Engines
1.2 Brief History of IC Engines
1.3 Types of IC Engines
1.4 Working of IC Engines
1.5 IC Engine – Cooling System
1.6 Heat Transfer
1.7 Heat Transfer through Fins
1.8 Fin Cross-Sections
1.9 Fin Materials
1.10 Fin Uses
1
1
2
2
3
4
6
8
10
11
11
2. Literature review 12
3. Single-Cylinder Four Stoke SI Engine
3.1 Engine Specifications
3.2 Cylinders
3.3 Pistons
3.4 Crankshaft & Connecting Rod
3.5 Flywheel
3.6 Heat Sink
16
16
17
18
18
18
4. Software’s Used
4.1 Introduction to Pro/E Wildfire 5.0
4.2 ANSYS CFX
19
21
5. Design of Fins
5.1 Rectangular Fin
5.2 Parabolic Fin
26
28
6. Modeling & Analysis
6.1 Pro/ENGINEER Modeling
6.1.1 Rectangular Fin
6.1.2 Trapezoidal Fin
6.1.3 Parabolic-1 Fin
6.1.4 Parabolic-2 Fin
33
34
36
37
6.2 Analysis in ANSYS
6.2.1 Rectangular Fin
6.2.2 Trapezoidal Fin
6.2.3 Parabolic-1 Fin
6.2.4 Parabolic-2 Fin
6.3 Bajaj Pulsar 150cc Engines
39
45
51
57
63
7. Results & Discussions
7.1 Comparison of Various Fin Parameters
7.2 Results
References
71
72
73
List of Figures
Fig no. Description Page no.
1.1 Stages of IC Engine Combustion 3
1.2 Triangular, Rectangular & Trapezoidal Fins 10
1.3 Parabolic & Cylindrical Fins 10
3.1
4.1
4.2
Single Cylinder 4-Stroke Engine
Spray Development in IC Engines
BorgWarner Turbo & Emission Systems
17
23
24
5.1 Rectangular Fin 26
5.2 Parabolic Fin (Case 1) 28
5.3 Parabolic Fin Efficiency 29
6.1 Pro/E model of Engine w/ Rectangular Fin 34
6.2 Pro/E model of Engine w/ Trapezoidal Fin 35
6.3
6.4
Pro/E model of Engine w/ Parabolic-1 Fin
Pro/E model of Engine w/ Parabolic-2 Fin
37
38
6.5
6.6
6.7
6.8
6.9
6.10
6.11
6.12
6.13
6.14
6.15
6.16
Meshed View (Rectangular Fin)
Temperature Contour (Rectangular Fin)
Heat Flux Contour (Rectangular Fin)
Stream Flow (Rectangular Fin)
Temperature Bar chart (Rectangular Fin)
Heat Flux Bar Chart (Rectangular Fin)
Temperature Vs Length (Rectangular Fin)
Velocity Vs Length (Rectangular Fin)
h Vs Length (Rectangular Fin)
Meshed View (Trapezoidal Fin)
Temperature Contour (Trapezoidal Fin)
Heat Flux Contour (Trapezoidal Fin)
40
41
41
42
42
43
43
44
44
46
47
47
6.17
6.18
6.19
6.20
6.21
6.22
6.23
6.24
6.25
6.26
6.27
6.28
6.29
6.30
6.31
6.32
6.33
6.34
6.35
6.36
6.37
6.38
6.39
6.40
6.41
6.42
6.43
6.44
Stream Flow (Trapezoidal Fin)
Temperature Bar chart (Trapezoidal Fin)
Heat Flux Bar Chart (Trapezoidal Fin)
Temperature Vs Length (Trapezoidal Fin)
Velocity Vs Length (Trapezoidal Fin)
h Vs Length (Trapezoidal Fin)
Meshed View (Parabolic-1 Fin)
Temperature Contour (Parabolic-1 Fin)
Heat Flux Contour (Parabolic-1 Fin)
Stream Flow (Parabolic-1 Fin)
Temperature Bar chart (Parabolic-1 Fin)
Heat Flux Bar Chart (Parabolic-1 Fin)
Temperature Vs Length (Parabolic-1 Fin)
Velocity Vs Length (Parabolic-1 Fin)
h Vs Length (Parabolic-1 Fin)
Meshed View (Parabolic-2 Fin)
Temperature Contour (Parabolic-2 Fin)
Heat Flux Contour (Parabolic-2 Fin)
Stream Flow (Parabolic-2 Fin)
Temperature Bar chart (Parabolic-2 Fin)
Heat Flux Bar Chart (Parabolic-2 Fin)
Temperature Vs Length (Parabolic-2 Fin)
Velocity Vs Length (Parabolic-2 Fin)
h Vs Length (Parabolic-2 Fin)
Pulsar Engine (Original)
Temperature Contour (Original)
Temperature Contour (Case 1)
Temperature Contour (Case 2)
48
48
49
49
50
50
52
53
53
54
54
55
55
56
56
58
59
59
60
60
61
61
62
62
63
63
64
64
6.45
6.46
6.47
6.48
6.49
6.50
6.51
6.52
6.53
6.54
6.55
6.56
Heat Flux Contour (Original)
Heat Flux Contour (Case 1)
Heat Flux Contour (Case 2)
Stream flow (Original)
Stream flow (Case 1)
Stream flow (Case 2)
Temperature vs. Length (Original)
Temperature vs. Length (Case 1)
Temperature vs. Length (Case 2)
Velocity vs. Length (Original)
Velocity vs. Length (Case 1)
Velocity vs. Length (Case 2)
65
65
66
66
67
67
68
68
69
69
70
70
i
List of Tables
Table
no.
Description Page no.
1
2
Mesh Information (Rectangular Fin)
Mesh Information (Trapezoidal Fin)
40
46
3 Mesh Information (Parabolic-1 Fin) 52
4 Mesh Information (Parabolic-2 Fin) 58
5
Comparison of various Profiles
71
ii
List of Symbols & Notations
Term Symbol/Notation
Efficiency η
Convective heat transfer coefficient
Fin Effectiveness
Fin Efficiency
Overall Surface Efficiency
Thermal Conductivity
Heat transfer along the length of Fin
Heat transfer at the base of Fin
Heat transfer without Fin
Fin Base Temperature
Surrounding Temperature
Bare Surface Area
Surface area of fin
Surface area of engine without fin
h
𝜖𝑓
𝜂𝑓
𝜂𝑜
K
𝑄𝑙
𝑄𝑏
𝑄𝑤𝑓
𝑇𝑏
𝑇∞
𝐴𝑏
𝐴𝑠
𝐴𝑤𝑓
iii
1
CHAPTER 1
1. Introduction
A fin is a surface that extends from an object to increase the rate of
heat transfer to or from the environment by increasing convection. Increasing
the temperature difference between the object and the environment, increasing
the convection heat transfer coefficient, or increasing the surface area of the
object increases the heat transfer. Sometimes it is not economical or it is not
feasible to change the first two options. Adding a fin to an object, however,
increases the surface area and can sometimes be an economical solution to heat
transfer problems. The Selection of a proper fin is very essential in establishing
the heat transfer as the fin’s shape and dimensions affect the heat transfer to
great extent. Our project deals with the design and analysis of various fin cross-
sections by CFD to determine the heat transfer for each fin and to find out the
effective cross-section.
1.1 About IC Engines
The internal combustion engine is an engine in which the
combustion of a fuel occurs with air inside a combustion chamber. In an internal
combustion engine, the expansion of the high-temperature and high –pressure
gases produced by combustion apply direct force to some component of the
engine. This force moves the component over a distance, transforming chemical
energy into useful mechanical energy.
The internal combustion engine can work in two, four and even in
six strokes. Commonly two-stroke IC engine are used in motor cycles and four-
stroke IC engine are used in automobiles, trucks etc.
2
The IC engines use fossil fuels like petrol (gasoline), diesel and some gaseous
fuels and a mixture of liquid-gas fuel.
1.2 Brief History of IC Engines
Christiaan Huygens designs gunpowder to drive water pumps, to
supply 3000 cubic meters of water/day for the Versailles palace gardens,
essentially creating the first idea of a rudimentary internal combustion piston
engine in 17th century. The engine was based on the Stirling cycle which is a
closed cycle regenerative cycle. Hence all engines having working principle
based on the Stirling cycle were named Stirling engines. In 1823, Samuel
Brown patented the first internal combustion engine to be applied industrially.
It was compression less and based on what Hardenberg calls the “Leonardo
cycle,” which, as the name implies, was already out of date at that time. Later in
1862, German inventor Nikolaus Otto was the first to build and sell the engine.
He designed an indirect-acting free-piston compression less engine whose
greater efficiency won the support of Eugen Langen and then most of the
market, which at that time was mostly for small stationary engines fuelled by
lighting gas. Rudolf Diesel demonstrated the diesel engine in the 1900 using
peanut oil (biodiesel)
1.3 Types of IC Engines
There are generally 2 main types of Stirling engines.
a) Reciprocating IC Engine
A Reciprocating IC engine consists of a piston in a cylinder which
is free to slide inside the cylinder along the stroke length. The piston has piston
rings which are in contact with cylinder walls.
3
The reciprocating output of the piston is converted to the rotational motion
using connecting rod and crank shaft. The rotational power generated is utilized
for useful purposes.
b) Rotary IC Engine
Wankel engine is a rotary IC engine. The Wankel engine (rotary
engine) does not have piston strokes. It operates with the same separation of
phases as the four-stroke engine with the phases taking place in separate
locations in the engine. In thermodynamic terms it follows the Otto engine
cycle, so may be thought of as a “four-phase” engine. While it is true that three
power strokes typically occur per rotor revolution due to the 3:1 revolution ratio
of the rotor to the eccentric shaft, only one power stroke per shaft revolution
actually occurs; this engine provides three power ‘strokes’ per revolution per
rotor giving it a greater power-to-weight ratio than piston engines.
1.4 Working of IC Engines
Fig 1.1 Stages of IC engine Combustion
4
Internal combustion engines have four basic steps that repeat with every two
revolutions for four-stroke and one revolution for two-stroke engine:
1. Intake stroke: The first stroke of the internal combustion engine is also
known as the suction stroke because the piston moves to the maximum volume
position (downward direction in the cylinder). The inlet valve opens as a result
of piston movement, and the vaporized fuel mixture enters the combustion
chamber. The inlet valve closes at the end of this stroke.
2. Compression stroke: In this stroke, both valves are closed and the piston
starts its movement to the minimum volume position (upward direction in the
cylinder) and compresses the fuel mixture. During the compression process,
pressure, temperature and the density of the fuel mixture increases.
3. Power stroke: When the piston reaches the minimum volume position, the
spark plug ignites the fuel mixture and burns. The fuel produces power that is
transmitted to the crank shaft mechanism.
4. Exhaust stroke: In the end of the power stroke, the exhaust valve opens.
During this stroke, the piston starts its movement in the minimum volume
position. The open exhaust valve allows the exhaust gases to escape the
cylinder. At the end of this stroke, the exhaust valve closes, the inlet valve
opens, and the sequence repeats in the next cycle. Four-stroke engines require
two revolutions.
Many engines overlap these steps in time: Jet engines do all steps
simultaneously at different parts of the engines.
1.5 IC Engine – Cooling System
In the Combustion Chamber, the fuel along with air is burned to
produce thermal energy.
5
This thermal energy is converted into mechanical energy by the piston &
cylinder setup and utilized to run the vehicle. Not all the thermal energy that is
produced is converted to useful work. Some energy is absorbed by the piston &
cylinder which raises the heat of the engine. The heating of engine parts is not
desired as it will damage the engine parts and burn the lubricants. So, cooling
must be done.
Engines with higher efficiency have more energy leave as
mechanical motion and less as waste heat. Some waste heat is essential: it
guides heat through the engine, much as a water wheel works only if there is
some exit velocity (energy) in the waste water to carry it away and make room
for more water. Thus, all heat engines need cooling to operate. Cooling is also
needed because high temperatures damage engine materials and lubricants.
Internal-combustion engines burn fuel hotter than the melting temperature of
engine materials, and hot enough to set fire to lubricants. Engine cooling
removes energy fast enough to keep temperatures low so the engine can survive.
Air-cooled and liquid-cooled engines are both used commonly.
Each principle has advantages and disadvantages, and particular applications
may favour one over the other. For example, most cars and trucks use liquid-
cooled engines, while many small airplane and low-cost engines are air-cooled.
a) Air-Cooled Engine
Cars and trucks using direct air cooling uses atmospheric air to
remove the heat from the engine. Fins are used for increasing the area of
exposure of the engine to the flowing air. The air at very high velocity flows
over the surface of the fins and collects the heat and it gets exhausted back into
the atmosphere. This uses both the conduction and forced convection mode of
heat transfer.
6
Advantage: “AIR” is naturally available in atmosphere. So, the coolant is
cheap and abundant. It also eliminates the need for some complex circuits
to handle the coolant. Thus making the engine more compact in size and
light in weight.
Disadvantage: The machining of fin follows number of processes and it is
considered to be tedious process. The heat transfer rate is not stable and
changes with temperature and pressure.
b) Liquid-Cooled Engine
Liquid-Cooling is mostly employed in marine vehicles which uses sea
water to remove the heat from engine. In some cases, chemical coolants are also
employed (in closed systems) or they are mixed with seawater cooling.
Advantage: Heat transfer from the engine to the sea water is high.
Disadvantage: Because of the high temperature and pressure of sea water
acquired by collecting the heat from the engine cylinder, the sea water
becomes an agent to cause severe corrosion in the coolant pipes. When the
atmospheric temperature is very low, it freezes the coolant and it stuck in
the pipelines. Thus causing a trouble to start the engine.
1.6 Heat Transfer
Heat transfer is concerned with the generation, use, conversion
and exchange of thermal energy and heat between physical systems. The heat
exchanging aspect found its application in most of the cooling systems in
automobile and various manufacturing machines used in workshops. So, the
exchange of heat between the system and surrounding must be effective in order
to reduce the power input and increases the power output.
7
The Heat transfer can takes place through all the phases of matter
i.e. Solids, liquids, gases and even through vacuum. Depending on the mode of
heat transfer, it is classified as:
➢ Conduction
➢ Convection
➢ Radiation
The convection mode of heat transfer found its application in most
of the automobile parts and in almost all the industries in the present world.
Convection is defined as transfer of heat from one place to
another through the bulk motion of the fluids. The fluid collects the heat from a
solid or another fluid through diffusion and transfers it to other substrate.
Among the three mode of heat transfer, the behaviour of the
convective heat transfer is complicated and the rate of heat transfer is not
constant. The rate of heat transfer is influenced by a number of parameters
which change with time. So, the design of the convective system must be
optimized to improve the efficiency and effectiveness of the system.
Mathematically the convective heat transfer is represented by
Newton’s law of Cooling: which states that “The rate of heat loss of a body is
proportional to difference in temperatures between the body and its
surroundings”. It is given by
𝑑𝑄
𝑑𝑡 = �̇� = ℎ. 𝐴. (𝑇𝑒𝑛𝑣 − 𝑇(𝑡)) = −ℎ. 𝐴∆𝑇(𝑡)
Where,
Q is thermal energy in joules
h is heat transfer co-efficient
8
A is surface area of heat being transferred
T is temperature of objects surface and interior
Tenv is the temperature of environment
ΔT(t) is the time-dependent thermal gradient between
environment and object.
One possible approach for development is to vary the surface area
and the heat transfer co-efficient to improve the rate of heat transfer.
1.7 Heat Transfer through Fins
The Rate of heat transfer in the fin is affected by number of fixed
and variable parameters which makes it more complex to determine the
performance of the fin. The performance varies independently. The heat transfer
from a fin is influenced by many fixed and variable parameters such as air flow
velocity, temperature, heat flux at cylinder wall, fin geometry, size, shape,
material etc.
Fin performance can be described in three different ways. To
optimize the fin performance, modifications are done to improve all the
following factors.
Fin Effectiveness: It is the ratio of the fin heat transfer rate to
the heat transfer rate of the object if it had no fin. It is denoted by εf.
𝜖𝑓 = 𝑞𝑓
ℎ. 𝐴𝑐,𝑏 . 𝜃𝑏
Where Ac.b is the fin cross-sectional area at the base.
9
Fin Efficiency: It is the ratio of the fin heat transfer rate to the
heat transfer rate of the fin if the entire fin were at the base temperature. It is
denoted by ηf.
𝜂𝑓 = 𝑞𝑓
ℎ. 𝐴𝑓 . 𝜃𝑏
Af in this equation is equal to the surface area of the fin. Fin
efficiency will always be less than one.
This is because assuming the temperature throughout the fin is at
the base temperature would increase the heat transfer rate.
Overall Surface Efficiency: It is the efficiency for an array of
fins. It is denoted by ηo.
𝜂𝑜 = 𝑞𝑡
ℎ. 𝐴𝑡 . 𝜃𝑏
Where At is the total area and qt is the sum of the heat transfer
rates of all the fins.
The fin performance and the heat transfer rate can be increased
in two different ways:
➢ To increase convection heat transfer coefficient h.
➢ To increase the surface area As.
Increasing h may require the installation of a pump or fan, or
replacing the existing pumps or fans with a larger ones. This approach in some
cases may or may not be practical. Besides in some cases, it may not be
adequate. The alternative is to increase the surface area by modifying the cross-
section of the fin.
10
1.8 Fin Cross-Sections
According to the Newton’s law of cooling,
Q=-h.A.ΔT
the rate of heat transfer is proportional to the surface area. So as the surface area
increases, the heat transfer and hence the fin performance increases. The cross-
section must be chosen in such a way that the surface area is more in order to
improve the area of contact with the fluid.
Some commonly used fins based on their cross-section is shown
below:
11
1.9 Fin Materials
Another way to increase the heat transfer is by selecting a proper
material which has a high thermal conductivity and less weight.
Aluminium is commonly used in making fin because of its
lighter weight. Aluminium is remarkable for the metal’s low density and for its
ability to resist corrosion due to the phenomenon of passivation.
Structural components made from aluminium and its alloys are
vital to the aerospace industry and are important in other areas of transportation
and structural materials. The most useful compounds of aluminium, at least on a
weight basis, are the oxides and sulphates. The thermal conductivity of
aluminium is 237 W·m−1·K−1
Other materials such as Copper ( 401 W·m−1·K−1 ), Steel etc. can
also be used.
1.10 Fin Uses
Fins are most commonly used in heat exchanging devices such
as radiators in cars and heat exchangers in power plants. They are also used in
newer technology such as hydrogen fuel cells. Nature has also taken advantage
of the phenomena of fins. The ears of jackrabbits and Fennec Foxes act as fins
to release heat from the blood that flows through them.
12
CHAPTER 2
2. Literature Review
Pulkit Agarwal, Mayur Shrikhande and P. Srinivasan [4].An air-cooled
motorcycle engine releases heat to the atmosphere through the mode of forced
convection. To facilitate this, fins are provided on the outer surface of the
cylinder. The heat transfer rate depends upon the velocity of the vehicle, fin
geometry and the ambient temperature. Many experimental methods are
available in literature to analyze the effect of these factors on the heat transfer
rate. However, an attempt is made to simulate the heat transfer using CFD
analysis. The heat transfer surface of the engine is modeled in GAMBIT and
simulated in FLUENT software. An expression of average fin surface heat
transfer coefficient in terms of wind velocity is obtained. It is observed that
when the ambient temperature reduces to a very low value, it results in
overcooling and poor efficiency of the engine.
Dhritiman Subha Kashyap [2].In the quest for designing better, more powerful
and fuel efficient engines, engine thermal management system design plays a
pivotal part. Optimal engine operating efficiency demands optimal heat transfer,
which, in turn, demands on accurate determination of the heat transfer co-
efficient. This parameter depends on a variety of factors like air flow speed over
the fins, operating temperature, fin width and pitch. Factors like air flow and
operating temperature change frequently, so predicting an all-encompassing
formula for predicting the heat transfer co-efficient is highly non-trivial in
nature. This paper looks at some efforts, both experimental and computer
simulations, to formulate this. Moreover, it also tries to evaluate the
assumptions used for deriving the formulas, in an effort to find the
shortcomings plaguing each of these in some aspect.
13
Rosli Abu Bakar, Chiew Chen Wee, Gan Leong Ming [6].The extended
surfaces for the cooling purpose were removable where it is attached onto the
engine block using fasteners. Two types of analyses were carried out, which are
the thermal analysis and the static analysis using the results from the thermal
analysis. The results showed that the removable fins are transferring heats like
normal fins but have higher temperature and the deformations are rather small.
The high temperature causes high thermal stresses on the cylinder assembly.
S.H. Barhatte, M. R. Chopade, V. N. Kapatkar [5].Extended surfaces,
commonly known as fins, often offer an economical and trouble free solution in
many situations demanding natural convection heat transfer. Heat sinks in the
form of fin arrays on horizontal and vertical surfaces used in variety of
engineering applications, studies of heat transfer and fluid flow associated with
such arrays are of considerable engineering significance. The main controlling
variable generally available to designer is geometry of fin arrays. Considering
the above fact, natural convection heat transfer from vertical rectangular fin
arrays with and without notch at the center have been investigated
experimentally and theoretically. Moreover notches of different geometrical
shapes have also been analyzed for the purpose of comparison and optimization.
In the present study, the fin flats are modified by removing the central fin
portion by cutting a notch. This paper presents an experimental analysis of the
results obtained over a range of, fin heights and heat dissipation rate. Attempts
are made to establish a comparison between the experimental results and results
obtained by using CFD software.
S. V. Naidu, V. Dharma Rao, B. Govinda Rao, A. Sombabu and B.
Sreenivasulu [1].The problem of natural convection heat transfer from fin arrays
with inclination is studied experimentally and theoretically to find the effect of
inclination of the base of the fin array on heat transfer rate.
14
A numerical model is developed by taking an enclosure, which is formed by
two adjacent vertical fins and horizontal base. Results obtained from this
enclosure are used to predict heat transfer rate from the fin array. All the
governing equations related to fluid in the enclosure, together with the heat
conduction equation in both the fins are solved by using Alternate Direct
Implicit method. Numerical results are obtained for temperature along the
length of the fin and in the fluid in the enclosure. The experimental studies have
been also carried out on two geometric orientations viz., (a) vertical base with
vertical fins (vertical fin array) and (b) horizontal base with vertical fins
(horizontal fin array), with the five different inclinations like 00, 300, 450, 600,
and 900. The experimental results are compared with the numerical results
computed by the theoretical analysis shows the good agreement”.
Esmail M.A. Mokheimer [7].Performance of annular fins of different profiles
subject to locally variable heat transfer coefficient is investigated in this paper.
The performance of the fin expressed in terms of fin efficiency as a function of
the ambient and fin geometry parameters has been presented in the literature in
the form of curves known as the fin-efficiency curves for different types of fins.
These curves, that are essential in any heat transfer textbook, have been
obtained based on constant convection heat transfer coefficient. However, for
cases in which the heat transfer from the fin is dominated by natural convection,
the analysis of fin performance based on locally variable heat transfer
coefficient would be of primer importance. The local heat transfer coefficient as
a function of the local temperature has been obtained using the available
correlations of natural convection for plates. Results have been obtained and
presented in a series of fin-efficiency curves for annular fins of rectangular,
constant heat flow area, triangular, concave parabolic and convex parabolic
profiles for a wide range of radius ratios and the dimensionless parameter m
based on the locally variable heat transfer coefficient.
15
The deviation between the fin efficiency calculated based on constant heat
transfer coefficient, reported in the literature, and that presently calculated based
on variable heat transfer coefficient, has been estimated and presented for all fin
profiles with different radius ratios.
Masao Yoshida, Soichi Ishihara, Yoshio Murakami, Kohei Nakashima and
Masagao Yamamoto [3].Effects of the number of fins, pitch, and wind velocity
were investigated using various experimental cylinders of air-cooled engine
motorcycle. Experimental cylinder that had different number of fins and pitches
were tested in a wind-tunnel. Then the temperature inside the cylinder, surface
of the fin and the in space between the fins were measured. Results indicated
that the heat transfer from the cylinder didn’t improve when the cylinder had
more no. of fins and too narrow a fin pitch at low velocities as it was difficult
for the air to flow into the narrower space between the fins and hence the
temperature increased. We also obtained the expression for the average surface
heat transfer coefficient derived from the fin pitch and wind velocity. This
expression is useful in fin design of an air-cooled engine.
16
CHAPTER 3
3. Single-Cylinder Four Stroke SI Engine
Various parts of the engine are described below.
3.1 Engine Specifications
Power: 9.7KW
Speed: 8700rpm
Torque: 11.68N @ 6500rpm
Compression Ratio: 9.5 ± 0.5:1
3.2 Cylinders
Cylinder is made of aluminium. In this cylinder, the actual
displacement of the piston due to expansion of the working fluid, namely air-
fuel mixture, takes place. This cylinder will have an extended surface for heat
transfer to take place. The cylinder will also have holes that will enable it to be
mounted on a stand by means of bolts. Various details about the engine cylinder
are as follows:
Cylinder Bore: 57mm
Cylinder Stroke: 57mm
Cylinder Thickness: 16mm
Engine Displacement: 150cc
17
3.3 Pistons
This piston is actually a hollow thin walled cylinder, made hollow
in order to reduce the weight. It is designed to function inside the displacement
piston.
It is made up of aluminium. The displacement piston has a long piston rod that
connects it to the connecting rod. The piston rod and the connecting rod are
connected to each other through a fork and pin arrangement.
Piston Outer Diameter: 57mm
Piston Inner Diameter: 50mm
Fig 3.1 Single Cylinder 4-Stroke Engine
18
3.4 Crankshaft & Connecting Rod
A connecting rod is used in this engine. The connecting rods are
attached to a crank shaft. The crank shaft converts the motion of the connecting
rods to a rotary motion.
Crankshaft is a shaft that transmits the motion generated by the
pistons to the flywheel. The purpose of connecting it to the flywheel is to have a
steady output, without any pulsation in output torque.
3.5 Flywheel
Flywheel is the inertial mass of the engine that makes the output
torque of an engine constant. The output torque of an engine does not stay
constant in all stages of operation of the engine, but varies at each stage. Such
pulsations will not result in desired working of the engine. Hence the flywheel
provides momentum to the crankshaft, making the whole operation smooth.
3.6 Heat Sink
The heat sink is a series of circumferential aluminium fins are a
part of the outer wall of the cylinder. Fins are extended surfaces that enhance
the heat transfer rate. The heat sink will lower the steady state temperature of
the cylinder.
Length of Fin: 38.5mm
Width of Fin: 1 – 3mm
Pitch: 10mm
No. of Fins: 12
19
CHAPTER 4
4.1 Introduction to Pro/ENGINEER Wildfire 5.0
Pro/ENGINEER Wildfire 5.0.release offers numerous
enhancements that set the bar for product development efficiency and
productivity. With a full range of integrated 3D CAD/CAM/CAE applications,
Pro/ENGINEER connects and ensures the seamless flow of digital product
information to cross-functional teams as well as to customers, partners, and
suppliers, whether or not they are Pro/ENGINEER users. Simple, powerful,
connected, Pro/ENGINEER Wildfire 5.0 improves both personal and process
productivity. A few of the enhancements in this new release are highlighted
below:
a) Streamline Detailed Design Processes
➢ Create and edit designs faster with a more intuitive user interface, real-
time model regeneration, simplified detailing workflows, and more.
➢ Accommodate design changes more confidently with greatly enhanced
failure diagnostics and recovery tools.
➢ Create spot, plug, fillet, and groove welds with ease using new weld
features, annotations, and simulation enhancements.
➢ Improve your design efficiency for plastic parts with a new rib tool,
curvature continuous rounds, sketch points and coordinate systems for
patterns, real-time previews for UDFs, and dynamic editing capabilities.
20
➢ Prevent product failures earlier in the design process with a new module
for electromechanical clearance and creepage analysis. You can identify
where an electrical current will jump gaps and creep along conductive
surfaces.
➢ Create pipes faster on the fly with a new Piping Design user interface.
➢ Bring products to life with enhanced, real-time photorealistic rendering.
Added support for shadows and reflections, perspective views, and
exploded-state animations shows your products to your advantage.
➢ Extend data exchange capabilities to leverage the most from imported
designs, including free support for Autodesk Inventor and Solid Works.
With industry-leading non geometric data exchange, you can preserve
3D notes, annotations, and metadata in neutral formats.
b) Easier Simulation, Verification, and Validation
➢ Create machine design simulation easier. You can drive slot motor
components along curves, quickly create belts to show kinematic and
dynamic coupling, analyze dynamic gears, and show 3D contact
simulations.
➢ Verify and validate designs faster with expanded analysis capabilities
such as heterogeneous units and support for materials plasticity. You can
streamline your workflow with an intuitive dashboard user interface for
surface and volume regions.
➢ Improved display for icons and labels enhances your visual cues.
21
➢ Provide more intuitive workflows, an easy-to-use tool manager, and
HTML-based process documentation for greater efficiency in production
machining. You can quickly and easily duplicate tool paths and leverage
the Process Manager for turning operations such as area turning,
grooving, and profile turning.
4.2 ANSYS CFX
ANSYS CFX software is a high-performance, general purpose
fluid dynamics program that has been applied to solve wide-ranging fluid flow
problems for over 20 years. At the heart of ANSYS CFX is its advanced solver
technology, the key to achieving reliable and accurate solutions quickly and
robustly. The modern, highly parallelized solver is the foundation for an
abundant choice of physical models to capture virtually any type of phenomena
related to fluid flow. The solver and its many physical models are wrapped in a
modern, intuitive, and flexible GUI and user environment, with extensive
capabilities for customization and automation using session files, scripting and a
powerful expression language.
ANSYS CFX is integrated into the unified ANSYS Workbench
platform, which forms the foundation for the industry’s broadest and deepest
suite of advanced engineering simulation technology. This easy-to-use platform
provides access to bi-directional parametric CAD connections, powerful
geometry and meshing tools, an automated project-level update mechanism,
pervasive parameter management, multiphysics simulation management, and
integrated optimization tools. As a result of these tight connections, ANSYS
CFX delivers benefits that include the ability to:
➢ Quickly prepare product/process geometry for flow analysis without
tedious rework
22
➢ Avoid duplication through a common data model that is persistently
shared across physics — beyond basic fluid flow
➢ Easily define a series of parametric variations in geometry, mesh, physics
and post-processing, enabling automatic new CFD results for that series
with a single mouse click
➢ Improve product/process quality by increasing the understanding of
variability and design sensitivity
➢ Easily set up and perform multiphysics simulations
The bottom line: ANSYS CFX delivers unprecedented
productivity in CFD simulation, enabling Simulation Driven Product
Development
a) Proven Solver Technology
ANSYS CFX runs robustly and efficiently for all physical
models and flow types including steady-state or transient, incompressible or
compressible flows (from low subsonic to hypersonic), laminar or turbulent
flows, Newtonian or non-Newtonian flows, and ideal or real gases.
For decades, ANSYS CFX software has focused on a solution strategy using
coupled algebraic multi-grid techniques that delivers fast and reliable
convergence that is completely scalable with mesh size, one that requires no
user input or numerical adjustments. In addition, it is insensitive to high-aspect
ratio mesh cells to allow boundary layers to be captured efficiently and
accurately. For maximum accuracy in all simulations, it uses second-order
advection schemes by default.
23
The solver delivers excellent performance on all types of problems and is
particularly powerful in flows in which inter-equation coupling is significant.
Examples of this include rotating flow with strong Coriolis terms, combusting
flows and high-speed flow with strong pressure gradients.
Careful discretization is necessary to provide robust and accurate
answers to the range of situations encountered in industrial CFD. ANSYS CFX
software's default high-resolution discretization delivers on both counts. The
adaptive central bounded numeric scheme locally adjusts the discretization to be
as close to second order as possible while ensuring stable simulation.
Fig.4.1 Spray development in internal combustion engines
b) Heat Transfer
Optimizing heat transfer can be critical in many types of
industrial equipment, like turbine blades, engine blocks and combustors, as well
as in the design of buildings and structures. In such applications, an accurate
prediction of convective heat transfer is essential. In many of these cases, the
diffusion of heat in solids and/or heat transfer by radiation also plays an
important role.
24
ANSYS CFX software features the latest technology for
combining fluid dynamics solutions using conjugate heat transfer (CHT) for the
calculation of thermal conduction through solid materials. The solid domain
meshes for CHT regions can be created independently, and then general grid
interfaces (GGI) used to attach any non-conformal meshes that are created.
Additional related features include the ability to account for heat conduction
through thin baffles, thermal resistance at contact areas between solids and
through coatings on solid surfaces, and advection in CHT solids due to motion.
ANSYS CFX incorporates a wealth of models to capture all types of radiative
heat exchange in and between fluids and solids — from fully and semi-
transparent to radiation, or opaque. The most flexible model is the Monte Carlo
model that simulates the physical interactions between photons and their
environment by tracing a representative number of rays through the simulation
domain. It can simulate any variation from optically thick to thin (or
transparent) media, both in fluids and solids. To maximize efficiency, the
radiation mesh can be automatically coarsened in regions in which changes in
the radiation field are small.
Fig 4.2 Detailed analysis of fluid flow through automotive turbocharger turbine
ANSYS CFX Courtesy BorgWarner Turbo & Emission Systems.
25
c) Improved Design Point Behaviour
Only design points affected by a change to the project will be
marked as out of date. Any change that is not relevant to the parametric study,
such as adding a standalone system or making a change downstream of the
parametric study, will not cause design points to go out of date. Likewise, only
the out-of-date components and systems will be updated during a design point
update operation. The improved behaviour often reduces the amount of time and
computer resources necessary for a design point update.
You can now specify whether design points will be updated
beginning from the current design point (DP0) or starting from the previous
design point. In some situations, it may be more efficient to update design
points starting from parameter values from the previous design point, rather
than starting from DP0 each time.
Output parameter values are now displayed in the Table of
Design Points and Details views as they are calculated. In previous releases, no
updated values were shown until the entire design point update was complete.
This capability allows design points that are only partially updated to show up-
to-date parameter values for those parameters which were updated successfully.
d) Using Excel with ANSYS Workbench Products
Leveraging the calculation capabilities of Microsoft Office Excel, you can now
perform parametric analyses to create design points and design exploration
studies via the Microsoft Office Excel option in the Component Systems
toolbox of ANSYS Workbench.
26
CHAPTER 5
5. Design of Fins: Thermal Analysis
5.1 Rectangular Fin
The Rectangular fin considered is 38.5mm long and 3mm thick.
This Rectangular fin is a circumferential fin which revolves around the engine
cylinder up to 360 degree.
Fig 5.1 Rectangular Fin
Efficiency of the rectangular fin from HMT data Book [17] is given by
η =
tan h [ml√(1 + r2r1
) 2⁄ ]
ml√(1 + r2r1
) 2⁄
Where m = √2h
kt
27
Heat transfer co-efficient, h = 100 W/m2K
Thermal Conductivity for Aluminium, k = 221.8 W/mK
Outer radius, 𝑟2 = 0.075m
Inner radius, 𝑟1 = 0.0365m
𝑚 = √2 x 100
221.8 x 0.003 = 17.33
Efficiency,
η =
tan h [17.33 x 0.0385√(1 + 0.0750.0365) 2⁄ ]
17.33 x 0.0385√(1 + 0.0750.0365) 2⁄
= 82.1%
Heat transfer along the length of fin, HMT data Book [17]
𝑄𝑙 = 𝜂 𝐴𝑠 ℎ (𝑇𝑏 − 𝑇∞)
As=0.30m2(Using Pro/E Software)
𝑄𝑙 = 0.821 x 0.30 x 100 x 74.038 = 1848.23W
Heat transfer at the base of the fin
𝑄𝑏 = 𝐴𝑏 ℎ (𝑇𝑏 − 𝑇∞)
Ab=.028m2(Using Pro/E Software)
𝑄𝑏 = 0.028 x 100 x 74.038 = 208.106W
28
Heat transfer from the system without fin
𝑄𝑤𝑓 = 𝐴𝑤𝑓 ℎ (𝑇𝑏 − 𝑇∞)
𝑄𝑤𝑓 = 𝜋 x 0.073 x 0.15 x 100 x 74.038 = 254.56W
Effectiveness, 𝜖 = 𝑄𝑓
𝑄𝑤𝑓 =
𝑄𝑙+𝑄𝑏
𝑄𝑤𝑓
ϵ = 1848.23 + 208.108
254.56 = 8.07
5.2 Parabolic Fin
Design 1: The one sided parabolic fin is considered to have a length of
38.5mm and sides of 3mm and 1mm.
Fig 5.2 Parabolic Fin (Case 1)
The X-axis of the graph is,
𝑚 = 𝐿 (2ℎ
𝑘𝐴𝑝)
12⁄
= 0.0385 (2 𝑥 100
225 𝑥 7.98 𝑒−5)1
2⁄= 0.6
29
Fig 5.3 Graph for Parabolic Fin Efficiency
ro/rb=0.075/0.0365=2.05
The corresponding value of efficiency for the curve m=0.6 & ro/rb=2.05 on Y-
axis is
Fin Efficiency, η = 87%
Heat transfer along the length of fin, HMT data Book [17]
𝑄𝑙 = 𝜂 𝐴𝑠 ℎ (𝑇𝑏 − 𝑇∞)
As=0.289m2(Using Pro/E Software)
𝑄𝑙 = 0.87 x 0.289 x 100 x 74.038 = 1866.1W
30
Heat transfer at the base of the fin
𝑄𝑏 = 𝐴𝑏 ℎ (𝑇𝑏 − 𝑇∞)
Ab=.028m2(Using Pro/E Software)
𝑄𝑏 = 0.028 x 100 x 74.038 = 208.108W
Heat transfer from the system without fin
𝑄𝑤𝑓 = 𝐴𝑤𝑓 ℎ (𝑇𝑏 − 𝑇∞)
𝑄𝑤𝑓 = 𝜋 x 0.073 x 0.15 x 100 x 74.038 = 254.56W
Effectiveness, 𝜖 = 𝑄𝑓
𝑄𝑤𝑓 =
𝑄𝑙+𝑄𝑏
𝑄𝑤𝑓
ϵ = 1866.1 + 208.108
254.56 = 8.14
Design 2: The two sided parabolic fin with its end trimmed is considered to
have a length of 38.5mm and sides of 3mm and 1mm.
The X-axis of the graph is,
𝑚 = 𝐿 (2ℎ
𝑘𝐴𝑝)
12⁄
= 0.0385 (2 𝑥 100
225 𝑥 7.98 𝑒−5)1
2⁄= 0.6
ro/rb=0.075/0.0365=2.05
31
The corresponding value of efficiency for the curve m=0.6 & ro/rb=2.05 on Y-
axis from the graph (Fig 5.3) is
Fin Efficiency, η = 87%
Fig 5.4 Parabolic Fin (Case 2)
Heat transfer along the length of fin, HMT data Book [17]
𝑄𝑙 = 𝜂 𝐴𝑠 ℎ (𝑇𝑏 − 𝑇∞)
As=0.291m2(Using Pro/E Software)
𝑄𝑙 = 0.87 x 0.291 x 100 x 74.038 = 1875.34W
Heat transfer at the base of the fin
𝑄𝑏 = 𝐴𝑏 ℎ (𝑇𝑏 − 𝑇∞)
Ab=.028m2(Using Pro/E Software)
𝑄𝑏 = 0.028 x 100 x 74.038 = 208.107W
32
Heat transfer from the system without fin
𝑄𝑤𝑓 = 𝐴𝑤𝑓 ℎ (𝑇𝑏 − 𝑇∞)
𝑄𝑤𝑓 = 𝜋 x 0.073 x 0.15 x 100 x 74.038 = 254.56W
Effectiveness, 𝜖 = 𝑄𝑓
𝑄𝑤𝑓 =
𝑄𝑙+𝑄𝑏
𝑄𝑤𝑓
𝛜 = 𝟏𝟖𝟕𝟓.𝟑𝟒 + 𝟐𝟎𝟖.𝟏𝟎𝟖
𝟐𝟓𝟒.𝟓𝟔 = 8.18
Similarly For a Trapezoidal Fin we get
Heat transfer along the length of fin, 𝑄𝑙= 1834.22W
Heat transfer at the base of the fin, 𝑄𝑏= 208.108W
Heat transfer from the system without fin, 𝑄𝑤𝑓= 254.156W
Effectiveness, 𝛜 = 𝟏𝟖𝟑𝟒.𝟐𝟐 + 𝟐𝟎𝟖.𝟏𝟎𝟖
𝟐𝟓𝟒.𝟓𝟔 = 8.02
33
CHAPTER 6
6. Modeling & Analysis
6.1 Pro/ENGINEER Modelling
6.1.1 Rectangular Fin
a) Modelling Sequence:
➢ Extrusion of engine cylinder.
➢ Revolution for extended surfaces.
➢ Pattern of extended surfaces.
➢ Profile Creation for inlet outlet sparkplug.
➢ Sweep profile section created above.
b) Detailed Procedure:
1. File – set working directory - Project – Ok
2. File – New – Part – Ok
3. Extrude – Define Internal Sketch – draw Hollow Circle – Depth – Ok
4. Revolve – Define Internal sketch – Profile section (Rectangle) – Ok
5. Pattern – Revolve – Direction – 1st direction – (7nos/13mm offset) – 2nd
direction – (6nos/13mm offset) – Ok
6. Sweep – Thin Projection – Sketch Profile – draw Section – enter
Thickness (2.5 mm) - Ok
7. Sweep – Thin Projection – Define internal Sketch – inlet/outlet valve
profile – Ok
8. Sweep – Cut – Sketch selection – use Profiles in 6 & 7 – Draw section –
Ok
9. Group 6, 7 & 8 – Mirror – select plane – Ok
34
10. File – Save – Ok
Fig 6.1 Pro/E model of Engine with Rectangular Fin
6.1.2 Trapezoidal Fin
a) Modelling Sequence:
➢ Extrusion of engine cylinder.
➢ Revolution for extended surfaces.
➢ Pattern of extended surfaces.
➢ Profile Creation for inlet outlet sparkplug.
➢ Sweep profile section created above.
b) Detailed Procedure:
1. File – set working directory - Project – Ok
35
2. File – New – Part – Ok
3. Extrude – Define Internal Sketch – draw Hollow Circle – Depth – Ok
4. Revolve – Define Internal sketch – Profile section (Parabolic 1) – Ok
5. Pattern – Revolve – Direction – 1st direction – (7nos/13mm offset) – 2nd
direction – (6nos/13mm offset) – Ok
6. Sweep – Thin Projection – Sketch Profile – draw Section – enter
Thickness (2.5 mm) - Ok
7. Sweep – Thin Projection – Define internal Sketch – inlet/outlet valve
profile – Ok
8. Sweep – Cut – Sketch selection – use Profiles in 6 & 7 – Draw section –
Ok
9. Group 6, 7 & 8 – Mirror – select plane – Ok
10. File – Save – Ok
Fig 6.2 Pro/E model of Engine with Trapezoidal fin
36
6.1.3 Parabolic-1 Fin
b) Modelling Sequence:
➢ Extrusion of engine cylinder.
➢ Revolution for extended surfaces.
➢ Pattern of extended surfaces.
➢ Profile Creation for inlet outlet sparkplug.
➢ Sweep profile section created above.
c) Detailed Procedure:
11. File – set working directory - Project – Ok
12. File – New – Part – Ok
13. Extrude – Define Internal Sketch – draw Hollow Circle – Depth – Ok
14. Revolve – Define Internal sketch – Profile section (Parabolic 1) – Ok
15. Pattern – Revolve – Direction – 1st direction – (7nos/13mm offset) – 2nd
direction – (6nos/13mm offset) – Ok
16. Sweep – Thin Projection – Sketch Profile – draw Section – enter
Thickness (2.5 mm) - Ok
17. Sweep – Thin Projection – Define internal Sketch – inlet/outlet valve
profile – Ok
18. Sweep – Cut – Sketch selection – use Profiles in 6 & 7 – Draw section –
Ok
19. Group 6, 7 & 8 – Mirror – select plane – Ok
20. File – Save – Ok
37
Fig 6.3 Pro/E model of Engine w/ Parabolic-1 Fin
6.1.4 Parabolic-2 Fin
a) Modelling Sequence:
➢ Extrusion of engine cylinder.
➢ Revolution for extended surfaces.
➢ Pattern of extended surfaces.
➢ Profile Creation for inlet outlet sparkplug.
➢ Sweep profile section created above.
b) Detailed Procedure:
1. File – set working directory - Project – Ok
2. File – New – Part – Ok
38
3. Extrude – Define Internal Sketch – draw Hollow Circle – Depth – Ok
4. Revolve – Define Internal sketch – Profile section (Rectangle) – Ok
5. Pattern – Revolve – Direction – 1st direction – (7nos/13mm offset) – 2nd
direction – (6nos/13mm offset) – Ok
6. Sweep – Thin Projection – Sketch Profile – draw Section – enter
Thickness (2.5 mm) - Ok
7. Sweep – Thin Projection – Define internal Sketch – inlet/outlet valve
profile – Ok
8. Sweep – Cut – Sketch selection – use Profiles in 6 & 7 – Draw section –
Ok
9. Group 6, 7 & 8 – Mirror – select plane – Ok
10. File – Save – Ok
Fig 6.4 Pro/E model of Engine w/ Parabolic-2 Fin
39
6.2 Analysis in ANSYS
The Pro/E model is converted into an .iges format and imported
into ANSYS Workbench for analysis.
6.2.1 Rectangular Fin
a) Analysis Sequence:
➢ Import the Pro/E model
➢ Creation of named selections
➢ Meshing of model
➢ Setup of run parameters
➢ Solution
➢ Post-Processing
b) Detailed Procedure:
1. File – New – Project – Ok
2. CFX solver – Geometry – import geometry – Rec.iges file - Ok
3. Named selections – Base, Cylinder head, Cylinder & Head Walls, Valves
& Spark Plug - Ok
4. Mesh – Automatic – Patch Independent - Ok
5. Setup – Domain 1 – Engine – Solid – Domain 2 – System – Fluid - Ok
6. Setup – Boundary – Inlet velocity – Turbulence - Ok
7. Setup – Boundary – Outlet Pressure – Relative - Ok
8. Setup – Boundary – Base, Cylinder Head – Temperature – Ok
9. Setup – Boundary – Cylinder wall, Fins – heat transfer co-efficient – Ok
10. Setup – Boundary – inlet/outlet valve, Spark Plug , Head walls - Ok
40
Fig 6.5 Meshed View
Table 1: Mesh Information
No. of Nodes 236353
No. of elements 1100183
Tetrahedra 1100183
11. Solution – Output control – no. of iterations (100) – Ok
12. Solution – Output control – Convergence Criteria (1 e-5) – Ok
13. Solution – Run – Ok
14. Results – Contours (Temperature, Heat Flux) – Stream line Flow – Chart
(Temp Vs Length ; Velocity Vs Length ; h Vs Length) – Ok
15. File – Save – project - Ok
45
6.2.2 Trapezoidal Fin
a) Analysis Sequence:
➢ Import the Pro/E model
➢ Creation of named selections
➢ Meshing of model
➢ Setup of run parameters
➢ Solution
➢ Post-Processing
b) Detailed Procedure:
1. File – New – Project – Ok
2. CFX solver – Geometry – import geometry – Trap.iges file - Ok
3. Named selections – Base, Cylinder head, Cylinder & Head Walls, Valves
& Spark Plug - Ok
4. Mesh – Automatic – Patch Independent - Ok
5. Setup – Domain 1 – Engine – Solid – Domain 2 – System – Fluid - Ok
6. Setup – Boundary – Inlet velocity – Turbulence - Ok
7. Setup – Boundary – Outlet Pressure – relative - Ok
8. Setup – Boundary – Base, Cylinder Head – Temperature – Ok
9. Setup – Boundary – Cylinder wall, Fins – heat transfer co-efficient – Ok
10. Setup – Boundary – inlet/outlet valve, Spark Plug , Head walls - Ok
46
Fig 6.14 Meshed View
Table 2: Mesh Information
No. of Nodes 244423
No. of elements 1138621
Tetrahedra 1138621
11. Solution – Output control – no. of iterations (100) – Ok
12. Solution – Output control – Convergence Criteria (1 e-5) – Ok
13. Solution – Run – Ok
14. Results – Contours (Temperature, Heat Flux) – Stream line Flow – Chart
(Temp Vs Length ; Velocity Vs Length ; h Vs Length) – Ok
15. File – Save – project - Ok
51
6.2.3 Parabolic-1 Profile
a) Analysis Sequence:
➢ Import the Pro/E model
➢ Creation of named selections
➢ Meshing of model
➢ Setup of run parameters
➢ Solution
➢ Post-Processing
b) Detailed Procedure:
1. File – New – Project – Ok
2. CFX solver – Geometry – import geometry – Para-1.iges file - Ok
3. Named selections – Base, Cylinder head, Cylinder & Head Walls, Valves
& Spark Plug - Ok
4. Mesh – Automatic – Patch Independent - Ok
5. Setup – Domain 1 – Engine – Solid – Domain 2 – System – Fluid - Ok
6. Setup – Boundary – Inlet velocity – Turbulence - Ok
7. Setup – Boundary – Outlet Pressure – relative - Ok
8. Setup – Boundary – Base, Cylinder Head – Temperature – Ok
9. Setup – Boundary – Cylinder wall, Fins – heat transfer co-efficient – Ok
10. Setup – Boundary – inlet/outlet valve, Spark Plug , Head walls - Ok
52
Fig 6.23 Meshed View
Table 3: Mesh Information
No. of Nodes 242087
No. of elements 1127783
Tetrahedra 1127783
11. Solution – Output control – no. of iterations (100) – Ok
12. Solution – Output control – Convergence Criteria (1 e-5) – Ok
13. Solution – Run – Ok
14. Results – Contours (Temperature, Heat Flux) – Stream line Flow – Chart
(Temp Vs Length ; Velocity Vs Length ; h Vs Length) – Ok
15. File – Save – project - Ok
57
6.2.4 Parabolic-2 Profile
a) Analysis Sequence:
➢ Import the Pro/E model
➢ Creation of named selections
➢ Meshing of model
➢ Setup of run parameters
➢ Solution
➢ Post-Processing
b) Detailed Procedure:
1. File – New – Project – Ok
2. CFX solver – Geometry – import geometry – Para-2.iges file - Ok
3. Named selections – Base, Cylinder head, Cylinder & Head Walls, Valves
& Spark Plug - Ok
4. Mesh – Automatic – Patch Independent - Ok
5. Setup – Domain 1 – Engine – Solid – Domain 2 – System – Fluid - Ok
6. Setup – Boundary – Inlet velocity – Turbulence - Ok
7. Setup – Boundary – Outlet Pressure – relative - Ok
8. Setup – Boundary – Base, Cylinder Head – Temperature – Ok
9. Setup – Boundary – Cylinder wall, Fins – heat transfer co-efficient – Ok
10. Setup – Boundary – inlet/outlet valve, Spark Plug , Head walls - Ok
58
Fig 6.32 Meshed View
Table 4: Mesh Information
No. of Nodes 254975
No. of elements 1190979
Tetrahedra 1190979
11. Solution – Output control – no. of iterations (100) – Ok
12. Solution – Output control – Convergence Criteria (1 e-5) – Ok
13. Solution – Run – Ok
14. Results – Contours (Temperature, Heat Flux) – Stream line Flow – Chart
(Temp Vs Length ; Velocity Vs Length ; h Vs Length) – Ok
15. File – Save – project - Ok
63
6.3 Bajaj Pulsar 150cc Engine
Fig 6.41 Pulsar Engine (Original)
Fig 6.42 Temperature Contour (Original)
71
CHAPTER 7
7.1 Comparison of Various Fin Parameters
Table 5: Comparison of Various Profiles
Parameters Rectangular Trapezoidal Parabolic-1 Parabolic-2
η 82% 84% 87% 87%
𝑸𝒍(W) 1848.3 1834.22 1866.3 1875.97
𝑸𝒃(W) 208.106 208.106 208.106 208.106
𝑸𝒘𝒇(W) 254.56 254.56 254.56 254.56
𝝐 8.07
Reference
8.02
(1% less)
8.14
(1% more)
8.18
(2% more)
Volume(𝒎𝟑) 7.99 𝑒−4 6.29 𝑒−4 6.61𝑒−4 5.85𝑒−4
Mass(kg) 2.16
Reference
1.70
(21% less)
1.79
(17% less)
1.53
(26% less)
Vmin(ms-1) 3 4.8 4.8 5.2
𝑻min(K) 343.3 342.1 342.4 339.8
Maximum
Heat
Liberated(W)
-1376 -1303 -1282 -1216
72
7.2 Results & Discussions
From the CFD analysis, it is inferred that the parabolic fins are
more preferable than existing cross-sections. Resistance to airflow is one of the
parameters which have been used for optimization. Parabolic fins have least
resistance to airflow and the minimum velocity is 3 – 5 m/s greater than the
existing design.
The Parabolic fins have minimum temperature that is possible
by means of convection. The minimum temperature is 4 – 5 ̊C lesser than the
existing design (Rectangular) which is observed in parabolic-2. The heat
generation rate follows the sequence which is as follows: Heat generation is
minimum for a rectangular profile and maximum for parabolic-2.
Surface area is maximum for the rectangular fin and minimum
for the parabolic-1. The efficiency of a parabolic fin depends on the width at
the base of the cylinder. If the width is increased then the heat liberated is
increased and the bare surface area is reduced.
Heat liberated varies from 1000 to 1500 W/m2. The maximum
heat flux is observed in the parabolic-2 and minimum heat transfer co-efficient
is observed in rectangular Effectiveness in various cases vary from 8-8.2 and it
is maximum for case-2 of parabolic fins.
The mass of the components is another parameter for
optimization. It is found that the case-2 of parabolic fins have the minimum
mass of 1.53 kg which is 25% less than the equivalent value in rectangular
case.
73
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Yoshida,JSME Intl Journal,2006
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Shrikhande and P. Srinivasan ,WCE 2011, July 6 - 8, 2011, London, U.K.
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