Conduction-Convection systems
and Fins
What are Fins ?
Fins are extended surfaces used to increase
the rate of heat transfer.
It is made of highly conductive materials such
as aluminum.
Analysis of Fins
Steady state operations
No heat generation
Constan

ChE 300: Transport Phenomena II
(Heat Transfer)
M. Mozahar Hossain PhD PEng
Department of Chemical Engineering
King Fahd University of Petroleum &
Minerals
Dhahran 31261, Saudi Arabia
Case 1: ?
Case-2
Case-2

Handouts [X
List of Symbol:
L Length
Lc Corrected n length (Chap. 2)
m Mass
r51 Mass rate of ow
M Molecular weight (Chap. ll)
:1 Molecular density
N Molal diffusion rate, moles per
unit time (Chap. 11)
p Pressure, usually N/ml, Pa
Perimeter
q Heat-transfe

Heat Exchangers
Heat Exchangers
Chee 318
1
Heat Exchangers
A heat exchanger is used to exchange heat between two fluids
of different temperatures, which are separated by a solid wall.
Heat exchangers are used to carry out energy conversion and
utilizati

Empirical and Practical Relations for
Forced-Convection Heat Transfer
Chapter 6
1
Introduction
Convection is the mechanism of heat transfer
through a fluid in the presence of bulk fluid motion.
It is classified as natural (or free) and forced
convection

Effectiveness-NTU method
1
This method is used when the inlet or outlet
temperatures are needed to be evaluated for
a GIVEN HEX.
The LMTD analysis frequently requires a
iterative solution.
The effectiveness-NTU method is based on the
effectiveness of t

Chapter 10
Heat Exchangers (HEX)
1
The application of the heat transfer principles
to the design of HEX is extremely important.
Economics play a key role in the design and
selection of HEX.
Weight and size are also important.
2
Heat exchangers are dev

Flow across tube bank
1
Because many heat exchanger
arrangements involve multiple row of
tubes, the heat transfer characteristics for
tube banks are of important interest.
Tube arrangements could be of two types:
staggered and in-line
2
3
Heat transfer

Steady-State Conduction
One Dimension
Start with the most general heat equation
Heat transfer in one direction
No heat generation
Steady state
Integrating
Fouriers law from x1 to x2 and from
T1 to T2
- For constant k
- For variable
Conduction Thermal Res

Unsteady State Conduction
Chapter 4
1
Transient Heat Conduction: Analytical Solution
Consider an infinite plate of thickness 2L, initial
temperature = Ti, at time equal zero the surfaces are
lowered to T=T1
2
Lumped Heat Capacity
Energy Balance:
Where

Flow across cylinders and
spheres
Flow across cylinders and spheres is important as the
flow inside tubes.
The boundary layer determines the heat transfer
characteristics.
The pressure gradient causes a boundary layer
separation on the back side when t

Radiation Heat Transfer
Chapter 8
1
Introduction
Conduction and convection heat transfer
require the presence of a medium while
radiation does not.
All objects with temperatures above absolute
zero radiate energy.
Energy is transferred by electromagnet

Chapter 3
Steady-State Conduction
Multiple Dimensions
The heat Equation
The heat flow in the x and y directions
The total heat flow at any point in the material
is the resultant of the qx and qy at that point
Isotherms and Heat Flow Lanes
Shape Factor

Chapter 5
Convection Heat Transfer
1
Introduction
In the previous chapters, we discussed the
mechanism and calculations of conduction
heat transfer.
Convection was considered only as a boundary
condition for the conduction problem.
In this chapter, we

Forced Convection
9 Fluid motion past a surface increases the rate of heat transfer
between the surface and the fluid.
9 For example, a brisk wind increases our discomfort on a cold
day.
9 A flowing fluid transports thermal energy by virtue of motion.
9 F

Chapter 3
One-Dimensional Steady-State Conduction
Chapter 3
Chee 318
1
Course Road Map
Chapter 1:
E in E g E out E st
Conservation of Energy
When there are no contributions of kinetic, potential, internal energy and work
E in qin
and E out qout
Can be wri

King Fahd University of Petroleum & Minerals
Department of Chemical Engineering
CHE-300: Transport Phenomena II (Heat Transfer)
Fall 2015 (Term 151)
Instructors:
Dr. Mamdouh A. Al-Harthi (Coordinator)
Dr. Isam Al-Jundi
Course Description:
Modes of heat t

King Fahd University of Petroleum & Minerals
Department of Chemical Engineering
CHE-300: Transport Phenomena II (Heat Transfer)
Spring 2014/2015 (Term 142)
Instructors:
Dr. Isam H. Aljundi (Coordinator)
Dr. Abdulhadi Aljuhani
Course Description:
Modes of