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 AssemblyArea of Interest

Theoretical Background

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lXX

S ji

lXX

S ij

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Theoretical Background (Cont.)

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ftt A

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bft ANAA

cf wLA 2

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c

cf mL

mLtanh

mLmkhmLxLmmkhxLm

b sinh)/(cosh)(sinh)/()(cosh

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

Length (m) thickness (m)width (m) Lc t P h k0.019 0.002 0.210 0.020 0.002 0.423 100.000 53.000

Af Ab At m nf θb qt0.008 0.013 0.064 43.644 0.800 0.632 55.410 651.498

Length (m) thickness (m)width (m) Lc t P h k0.019 0.002 0.210 0.020 0.002 0.423 100.000 252.000

Af Ab At m nf θb qt0.008 0.013 0.064 20.015 0.900 0.290 55.410 679.434

Steel Top Fins

Aluminum Top Fins

Temperature Distribution (Top Fins)

0

0.2

0.4

0.6

0.8

1

1.2

0 0.01 0.02 0.03 0.04 0.05

Length (m)

θ/θb

Aluminum

Steel

Results and Discussion: Side Fin Design Comparison Solutions

Length (m) thickness (m)width (m) Lc t P h k0.051 0.004 0.229 0.053 0.004 0.465 100.000 53.000

Af Ab At m nf θb qt0.024 0.010 0.083 30.959 0.580 1.173 55.410 583.892

Length (m) thickness (m)width (m) Lc t P h k0.051 0.004 0.229 0.053 0.004 0.465 100.000 252.000

Af Ab At m nf θb qt0.024 0.010 0.083 14.198 0.850 0.538 55.410 801.786

Steel Side Fins

Aluminum Side Fins

Temperature Distribution (Side Fins)

0

0.2

0.4

0.6

0.8

1

1.2

0 0.01 0.02 0.03 0.04 0.05

Length (m)

t/tb

Aluminum

Steel

Results and Discussion: Heat Transfer Comparison for Type III Design

Top Fins (W) Top Fins (W)Side Fins (W) Side Fins (W)Total (W) Total (W)

Δq (W) 245.8301481.220 1235.390

583.892651.498

Total Heat Transferred by Aluminum Fins Total Heat Transferred by Steel Fins679.434801.786

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_Files/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-546-

26532/Lab%20Projects/Project%>.

Questions