TOPIC :- EXTENDED SURFACE
HEAT TRANSFER
1
*ASSIGNMENT *
Department of dairy Technology

SUBMITTED BY :- HEMANT ARUN THAKARE
Enrollment No :- D/21/059
Course code :- DE-205 (HMT)
Submitted to :- Er. Santosh chopde sir
Date of submission :- 05/10/2022
2

• 1) Introduction
• 2) Fins
• 3) Why do we use fins ?
• 4)Types of fins
• 5)Application of extended surface
• 6) Advantages / Disadvantages
• 7) Some Assumption
• 8) Efficiency of fins
3
INDEX

INTRODUCTION :-
• An extended surface (also known as a combined conduction
and –convection).
• Extended surfaces may exist in many situation but are
commonly used as fins to enhance heat transfer by increasing
the surface area available for convection
4

5

• FINS :-
• Fins are the extended portion of surfaces .
• The heat is transferred from the body to fins by
means the conduction then this heat from the fins
Is transferred away by convection
• Without use of fins is insufficient to cool or heat
the Body ..
6

WHY DO WE USE THEFINS?
• To increase the rate of heat transfer
• To maintain the engine body temperature excessive amount
of heat is to be desipated
• To dissipitate heat more heat transfer area is needed
• Its helps to loose heat from engine to the air at a faster rate.
7

Straight fin
• TYPES OF FINS
2) Radial Fins :-
Radial fins are fitted on the cylinder
surface
*Used in Induction type motor
1)Straight Fins:- The straight
fins are arranged normally to the
surface of the body and in parallel
directions . These are uniform fins
Radial Fin
8

3) Annular fins :-
The annular fins are of annular shape
fixed on the periphery of the cylinder
body.
Used in liquid- gas heat exchanger
Annular Fin
4)Pin Fins :-
The fins have a lower cross section
area but in this case the surface area
Exposed to the conection is more
9

• APPLICATIONS OF EXTENDED SURFACE
Fins are most commonly used in heat exchanging devices .
• 1) Economisers for steam power plants
• 2) On engine surfaces in bikes
• 3) Compressors
• 4) Condensors of refrigerator or AC
• 5) Electric Transformer
• 6) On electric motor
• 7) Electric and electronic components
10

11

• 1) Steady state heat conduction
• 2) No internal heat generation within the fins
• 3) Uniform heat transfer coefficient(h) over the e
entire surface of fin
• 4) Homogenous and isotropic fins material
• 5) One dimensional heat conduction
• 6) Negligible Radiation
The following assumption are made for the analysis of heat
Heat flow through fin are
12

EFFICIENCY OF FINS :-
1)Fin efficiency is the ratio of heat transfer from the actual
fin to the heat transfer of an imaginary fin
EFFECTIVENESS:-
Fin effectiveness shows the relation between the rate of
Heat transfer By using fins and by without using fins
13

ADVANTAGES OF FIN :-
• Increase the rate of heat transfer
• Easy and cheap way For cooling of equipment’s
• Its not necessary to increase the Convective heat transfer
By using the differentcooling medium
Disadvantage :-
• The weight of body increase due to the Fins .
14

THANKING YOU ..
15