This document discusses extended surfaces and fins for heat transfer. It begins with an introduction to extended surfaces and fins, explaining that fins are extended surfaces that increase the available surface area for convection. It then describes different types of fins like straight, radial, and annular fins. Applications of fins in heat exchangers, engines, and electronics are provided. The document also discusses the assumptions made in fin analysis, defines fin efficiency and effectiveness, and lists advantages and disadvantages of using fins.

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

2. 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

3. • 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

4. 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. 5

6. • 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

7. WHY DO WE USE THE FINS ?
• 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

8. 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

9. 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

10. • 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. 11

12. • 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

13. 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

14. 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 different cooling medium
Disadvantage :-
• The weight of body increase due to the Fins .
14

15. THANKING YOU ..
15