Fin Design for Maximum
Thermal Dissipation
ME 450: Computer Aided Engineering Analysis
Instructor: Dr. Nema
Group Members:
Wei-Yuan Chu, Brad Holtsclaw, Nick Metzger,
Breanne Walters
Objectives


Maximize Thermal Dissipation by
Designing a Fin System that will Draw
Heat Away from the Engine Casing
Using Aluminum Alloy and Carbon Steel
as Materials, we will analyze which
material makes a better fin.
Introduction



Engine is used to run a small blower
It is assumed that the motor casing will be
subjected to cooling by a fan or other suitable
ventilation.
Main area of concern is drawing heat into the
fin system in order to dissipate it into the air.
Complete Assembly
Area of Interest
Theoretical Background




E in  E g  E out  E st
dT
dT
dT
q  kT  k (i
j
k
)
dr
d
dz
''
;
q ''  h(T  Ts )
Si 
Xj X
l
Sj 
X  Xi
l
Theoretical Background (Cont.)
 NA f

qt  hAt 1 
(1   f ) b
At


At  NA f  Ab
A f  2 wLc
Lc  L 
f 
t
2
tanh mLc
mLc
 cosh m( L  x)  (h / mk ) sinh m( L  x)

b
cosh mL  (h / mk ) sinh mL
Model Details (Solid Modeling)
Solid Models were created in Pro-Engineer and
Converted to IGES Files to Import into Ansys
Model Details (Type I)



SOLID 92
Element Type
5,829 Elements
10,706 Nodes
Model Details (Type II)



SOLID 92
Element Type
16,196 Elements
29,355 Nodes
Model Details (Type III)



SOLID 92
Element Type
16,196 Elements
29,355 Nodes
Boundary Conditions

Temperature of
65.56oC applied to
Internal Surface to
Simulate Operating
Conditions
Boundary Conditions (Cont.)


Ambient
Temperature of
10oC
Film Coefficient of
100 W/m*oC (for
cooling airspeed
of 10 m/s)
Results and Discussion:
S.S. Temperature Distribution
(Type I) – Steel Top Fins


Carbon
Steel Top
Fins
Max.
Temp. in
Fins is
55.078oC
Results and Discussion:
S.S. Temperature Distribution
(Type I) – Aluminum Top Fins


Aluminum
Top Fins
Max.
Temp. in
Fins is
60.218oC
Results and Discussion:
S.S. Temperature Distribution
(Type II) – Steel Top Fins


Steel Top
Fins
Max.
Temp. in
Fins is
50.885oC
Results and Discussion:
S.S. Temperature Distribution
(Type II) – Aluminum Top Fins


Aluminum
Top Fins
Max.
Temp. in
Fins is
55.777oC
Results and Discussion:
S.S. Temperature Distribution
(Type III) – Steel Top and Side Fins


Steel Top
and Side
Fins
Max.
Temp. in
Fins is
50.885oC
Results and Discussion:
S.S. Temperature Distribution
(Type III) – Aluminum Top and Side Fins


Aluminum
Top and
Side Fins
Max.
Temp. in
Fins is
55.777oC
Results and Discussion:
Transient Response
(Type III) – Aluminum Top and Side Fins
Results and Discussion: Top Fin Design
Comparison Solutions
Temperature Distribution (Top Fins)
Aluminum
1.2
Steel
1
θ/θb
0.8
0.6
0.4
0.2
0
0
0.01
0.02
0.03
0.04
0.05
Length (m)
Steel Top Fins
Length (m) thickness (m)
width (m)
0.019
0.002
0.210
Af
Ab
At
0.008
0.013
0.064
Aluminum Top Fins
Length (m) thickness (m)
width (m)
0.019
0.002
0.210
Af
Ab
At
0.008
0.013
0.064
Lc
t
0.020
m
P
0.002
nf
43.644
Lc
0.800
t
0.020
m
P
0.002
nf
20.015
0.900
h
k
100.000
53.000
θb
qt
0.632
55.410
651.498
0.423
h
k
100.000
252.000
θb
qt
0.290
55.410
679.434
0.423
Results and Discussion: Side Fin Design
Comparison Solutions
Temperature Distribution (Side Fins)
Aluminum
1.2
Steel
1
t/tb
0.8
0.6
0.4
0.2
0
0
0.01
0.02
0.03
0.04
0.05
Length (m)
Steel Side Fins
Length (m) thickness (m)
width (m)
0.051
0.004
0.229
Af
Ab
At
0.024
0.010
0.083
Aluminum Side Fins
Length (m) thickness (m)
width (m)
0.051
0.004
0.229
Af
Ab
At
0.024
0.010
0.083
Lc
t
0.053
m
P
0.004
nf
30.959
Lc
0.580
t
0.053
m
P
0.004
nf
14.198
0.850
h
k
100.000
53.000
θb
qt
1.173
55.410 583.892
0.465
h
k
100.000 252.000
θb
qt
0.538
55.410 801.786
0.465
Results and Discussion: Heat Transfer
Comparison for Type III Design
Total Heat Transferred by Aluminum Fins
Top Fins (W)
679.434
Side Fins (W)
801.786
Total (W)
1481.220
Total Heat Transferred by Steel Fins
Top Fins (W)
651.498
Side Fins (W)
583.892
Total (W)
1235.390
Δq (W)
245.830
Impact Statements

The Addition of Fins will Aid in the Heat
Dissipation from the Motor Casing, making the
Part More Safe for General Use

Motor Casing with Type III Fins Will have a
Reduced Surface Temperature and Less of a
Chance of Overheating the Interior Electronics
and Causing a Fire
Conclusions



Total Heat Transferred from Aluminum
Fin is 245.83 W Greater than that from
the Steel Fin.
Efficiency for Aluminum Fin is Greater
than that of Steel.
Aluminum is the Best Choice for the Fin
Material.
References
Nematollahi, Khosrow. "Oncourse, ME 450." Scheduled Reading and Assignments.
IUPUI. 23 Apr 2007
<https://oncourse.iu.edu/access/content/user/knematol/Filemanager_Public_Fil
es/ME450LectureNotesCh13r>.
Incropera, Frank, David Dewitt, and Theodore Bergman. Fundamentals of Heat and
Mass Transfer. 6th. Hoboken NJ: Wilet & Sons, 2007.
Rengifo, Gustavo. "Oncourse, ME 546." ME 546 Resources, Project #1. IUPUI. 23
Apr 2007 <https://oncourse.iu.edu/access/content/group/SP07-IN-ME-54626532/Lab%20Projects/Project%>.
Questions