LECTURE 1

29 March 2021

Heat Transfer
PPE-211
Dr Atif Javaid

atifjavaid@uet.edu.pk
Department of Polymer & Process
Engineering, UET, Lahore
Outline
 Course Details
 Course Objectives and Learning
Outcomes
 Course contents
 Reading materials
 Course details
 Course basics
Course Objectives
• Providing a general introduction to heat
transport phenomena which will equip
students with skills and knowledge
necessary to quantitatively analyse systems
and processes where the phenomena play a
critical role.
• Understand fundamentals of heat transfer
mechanisms in fluids and solids and their
applications in various heat transfer
equipment in process industries
Course Learning Outcomes (CLOs)
Students should be able to,

CLO-1: To understand the theory of heat transfer with

respect to its applications in process industry. (PLO1; C1)

CLO-2: To apply techniques and knowledge of heat

transfer in selection and design of heat transfer equipment
(PLO-3; C3).
 Course Contents
SECTION-I
(a) Introduction: Modes of heat transfer and their governing equations
(b)Heat transfer by conduction in solids: Basic law of conduction, thermal
conductivity, steady state conduction and unsteady state conduction
(c) Principles of heat flow in fluids : Typical heat exchange equipment, heat flux
and heat transfer coefficients

SECTION-II
(a) Heat transfer to fluids without phase change: Boundary layers, heat transfer
by forced convection in turbulent flow, effect of roughness, natural
convection and heating and cooling of fluids in forced convection
(b)Heat transfer to fluids with phase change: Heat transfer from condensing
vapors, drop-wise and film type condensation, Nusselt equations, heat
transfer to boiling liquids, sub-cooled boiling , pool boiling, thermo-siphon
re-boilers and forced circulation re-boilers
 Course Contents cont’d
SECTION-III
(a) Heat-exchange equipment: General design of heat exchange equipment,
shell and tube heat exchangers, 1-1 exchanger, tube and tube sheets, shell
and baffles, multi-pass exchangers and 2-4 exchangers
(b)Correlations of LMTD in multi-pass exchangers: Heat transfer coefficients
in shell and tube exchangers, choice of tube side fluid, cross-flow
exchangers
(c) Types of heat exchangers: Plate type exchangers, extended surface
equipment, type of extended surface and scraped surface exchangers
(d)Design of Heat Exchangers: Counter-flow double pipe exchanger, 1-2
Parallel-counterflow shell and tube exchanger
(e) The Effectiveness-NTU method
SECTION-IV
(a) Condensers and vaporizers
Evaporation: Types of evaporators, single effect and multiple effect
evaporators, performance of tubular evaporators , methods of feeding and
vapor recompression
 Reading Materials
Text Books:
 TL. Bergman, AS. Lavine, FP. Incropera, DP. DeWitt,
Fundamentals of Heat and Mass Transfer, 8th Edition,
Wiley, 2017. ISBN: ES8-1-119-32042-5.
 WL. McCabe, JC. Smith, and P. Harriott, Unit Operations
of Chemical Engineering. 7th ed., New York, McGraw-
Hill, 2005. ISBN: 9780072848236
Reference Books:
 DQ. Kern, Process Heat Transfer, McGraw-Hill, 1950
(ISBN: 9780074632178)
 YA. Cengel, Heat Transfer: A Practical Approach, 2nd
Edition, McGraw-Hill, 2002 (ISBN-13: 978-0072458930)
 JM. Coulson and JF. Richardson, Chemical Engineering:
Fluid Flow, Heat Transfer, and Mass Transfer, 6th Edition,
Butterworth-Heinemann, 1999 (ISBN: 9780750644440)
 M. Peters, K. Timmerhaus, R. West, Plant Design and
Economics for Chemical Engineers, Fifth Edition,
McGraw-Hill, 2002.
 Course Distribution
COURSE OVERVIEW
Week Topics Recommended Readings Objectives CLO PLO
TL Bergman, AS Lavine,
FP Incropera, DP DeWitt, Heat Transfer and
Basics of Heat Fundamentals of Heat and Thermodynamics
1 CLO1 PLO1
Transfer Mass Transfer, 8th Conduction
Edition, Wiley, 2017. Convection
Chap 1
Basics of Heat TL Bergman, AS Lavine, Radiation CLO1 PLO1
Transfer FP Incropera, DP DeWitt,
Fundamentals of Heat and
Heat Transfer Mass Transfer, 8th
2 by Conduction Edition, Wiley, 2017. Steady-state conduction CLO1 PLO1
Principles of Chap 1
heat flow in W. L. McCabe et. al., Unit Typical heat exchange CLO1 PLO1
fluids Operations of Chemical equipment
Engineering, Ch. 10, 11
 Course Distribution
Principles of heat Energy balance, Heat flux; Log CLO1 PLO1
flow in fluids Mean Temperature Difference
Heat transfer to (LMTD), Individual and overall
3
fluids without heat-transfer coefficients,
phase change Nusselt number; Prandtl and
TL Bergman, AS Lavine, thermal Boundary layers CLO1 PLO1
FP Incropera, DP Heat transfer by forced CLO1 PLO1
Heat transfer to
DeWitt, Fundamentals of convection in turbulent flow
4 fluids without
Heat and Mass Transfer, Estimation of wall temperature CLO2 PLO3
phase change
8th Ed, Wiley, 2017. Effect of roughness
Heat transfer to boiling liquids, CLO1 PLO1
Heat transfer to sub-cooled boiling , pool CLO2 PLO3
5 fluids with phase boiling, thermo-siphon re-
change (Boiling) boilers and forced circulation
re-boilers
 Course Distribution
TL Bergman, AS Lavine, FP CLO1 PLO1
Heat transfer to
Incropera, DP DeWitt, Heat transfer from condensing CLO2 PLO3
fluids with
6 Fundamentals of Heat and vapors, drop-wise and film type
phase change
Mass Transfer, 8th Edition, condensation, Nusselt equations
(Condensation)
Wiley, 2017.
Double Pipe Exchangers CLO1 PLO1
Calculations for Film CLO2 PLO3
Counterflow:
Coefficients; Calculations for
7 Double Pipe
Pressure Drop in Pipes and Pipe
Exchangers
Annuli; Design of a Double Pipe
Benzene-Toluene Exchanger
D Q Kern, Process Heat
Double Pipe Exchangers in CLO1 PLO1
Transfer, Chapter 6
Series-parallel Arrangements CLO2 PLO3
Counterflow: The True Temperature Difference;
8 Double Pipe Design of a Example 6.S. Double
Exchangers Pipe Lube Oil-Crude Oil
Exchanger in Series-parallel
Arrangement
9 MIDTERM
 Course Distribution
D Q Kern, Process The Calculation of an Existing 1-2 CLO2 PLO3
10
Shell & Tube Heat Transfer, Chapter Exchanger
11 Heat Exchanger 7,8 Exchangers Using Water CLO2 PLO3
12 Calculation of Existing 2-4 Exchanger CLO2 PLO3
TL Bergman, AS Types of heat exchangers: Plate type CLO1 PLO1
Heat-exchange Lavine, FP Incropera, exchangers, extended surface CLO2 PLO3
13
equipment DP DeWitt, equipment, type of extended surface
Fundamentals of Heat and scraped surface exchangers
Heat-exchange and Mass Transfer, 8th CLO1 PLO1
14 Condensers and vaporizers
equipment Edition, Wiley, 2017.
Types of evaporators, single effect CLO1 PLO1
15 Evaporation
W. L. McCabe et. al., and multiple effect evaporators CLO2 PLO3
Unit Operations of Performance of tubular evaporators , CLO1 PLO1
16 Evaporation Chemical Engineering methods of feeding and vapor CLO2 PLO3
recompression
17 FINAL EXAMINATION
Course Details
Course Work: 3 Credit Hours & Contact Hours
Laboratory Work: 1 Credit Hour and 3 Contact Hours
Weekly Lectures:
Lecture 5-6 - Monday, Lecture 3-4 – Tuesday
Lectures Breakdown is in course file (available in Class Lectures
on MS Teams)
Assessment:
Mid Term Examination (30%)
Final Examination (40%)
2 Short MCQ type quizz during the course duration (20%)
One assignment (to be submitted electronically via Turnitin) &
One 5-min presentation on a specific topic (ALREADY
STUDIED PREVOUSLY) during the course duration (10%)
 Regular Oral Question/Answer sessions
Attendance 75% Attendance is mandatory
Focus of the course
• (Equilibrium) Thermodynamics deals mainly with
systems in equilibrium and their properties
• This course deals with rate processes in systems which
are not in equilibrium
• Transport of heat : conduction, convection, radiation
• Main goal is to understand the roles and effects of
different heat transport processes
• Various representative applications in physical, chemical
and biological applications are examined
Heat Transfer vs Thermodynamics
• Thermodynamics: energy can be transferred by
interactions (work and heat) of a system with its
surroundings. Thermodynamics deals with the end states
of the process during which an interaction occurs and
provides no information concerning the nature of the
interaction or the time rate at which it occurs.

• Heat transfer (or heat) is the movement of thermal

energy due to a temperature difference. Whenever a
temperature difference exists in a medium or between
media, heat transfer must occur.
Structure of subject
• Basic concepts and laws
• Mathematical formulation of laws
• Use of appropriate mathematical formulation in
particular physical setting (mathematical model
formulation)
• Analysis of mathematical formulation
• Interpretation of results (what do you learn?)
• Use of physical intuition+ mathematical analysis
• Maths is used as a language
• Subject has the flavor of engineering-science
Emphasis of course
• Course emphasizes real understanding of
underlying principles as opposed to remembering
facts
• Use of first principles approach to employ
concepts to new applications
• No spoon feeding (spoon feeding is crippling)
• An adequate understanding of principles involves
being able to employ them in new situations
(problem solving is crucial)
• Emphasize broad scope of subject
How to approach the course

• Be patient!
• Keep an open mind
• Work persistently
• Don’t dissipate energy resisting
• Get used to different styles of teaching/learning: don't expect
similar styles as those in college
• Serious mentally engagement with the subject required
• Do not have preconceived notions about engineering, science,
“theory”, applications or even what may be interesting or relevant
• Challenge yourself!
• Take an exploratory approach to the subject(s) and find things
that interest you
Applications of transport processes:
Chemical Engineering

• Heat transport applications: Boiling, heat

exchangers, condensation
• Mass transport applications: absorption,
distillation, evaporation.
• Examples from both traditional as well as
emerging areas of chemical engineering

Applications in aeronautical, mechanical, materials, biomedical,

environmental systems
Other applications in Engineering

• Solar radiation and energy transfer

• Transport of pollutants in the atmosphere
• Dynamics of the atmosphere
• Response of materials in a variety of settings (eg
rocket/air flight, nuclear reactors)
• Fabrication and manufacture of products/materials

Semiconductor processing: chemical vapour deposition

Introduction
Functions
• A function is a relation which associates a real number x, with
another real number f(x)
• The real numbers x lie in a set called the domain
• Functions can be described by their graph (a plot of y=f(x) vs x)
• Can generalize this notion to functions of many variables: g(x,y):
Graph: z= g(x,y)
• Physical significance: functions are the basic way of describing
continuous processes/systems
(Domain of functions usually have an interval e.g.: [a,b], or [0, ∞])
• The notion of a field (e.g. Velocity field, temperature field)
Introduction
Derivatives
• Continuous function : Particular class of functions such that at
any point x0, lim (x  x0) f(x) exists and is equal to the value
of the function there, f(x0)

• Derivative of a function:
df/dx= lim (h  0) [f(x+h) –f(x)]/h
(assuming this limit exists)
• For a function to be differentiable at any point it is necessary
(but not sufficient) that it is continuous
• Derivative represents the rate of change of f w.r.t x
Introduction
Integration
Integration is essentially a continuous summation
Problem: Given a function f(x), find the area under the curve
between x= a and x=b
b
A   f(x)dx
a

Integration either indefinite or definite

Integration is the opposite operation to differentiation

 df 
b
f(b) - f(a)    dx
a
dx 
Physical examples: measures area under the curve of f, from a to b
Introduction
Functions of many variables
Given function f(x,y), can define partial derivatives (one variable at
a time)
f f Derivative of the function w.r.t one variable
,
x y keeping the other fixed
Can repeat the differentiation operation to obtain higher derivatives
 2f  2f  2f
, 2,
x y xy
2

2 f 2 f
For most “well-behaved” functions 
xy yx
Introduction

Gradient
Consider a function of three spatial variables x,y,z
f(x,y,z)
 f f f 
Gradient function f   , , 
 x y z 

The gradient function is a vector: its x-component contains

information of the rate of change of f w.r.t x, and similarly for y
and z components
Introduction
Heat & Heat Transfer
• Heat: Heat is energy! Heat is the energy transferred (passed)
from a hotter object to a cooler object.
• Heat Transfer: Transfer (passing) of heat from one object to
another due to temperature gradient. Heat always moves in
direction from: higher temperatures to lower temperatures.
warm to cool
• Always! Always! Always from high energy to low!
• Hot objects in a cooler room will cool to room temperature.
• Cold objects in a warmer room will heat up to room
temperature.
Introduction
Question #1
• If a cup of coffee and an ice cream were left on
the table in a room what would happen to them?
Why?
• Cup of coffee will cool until it reaches room
temperature. Ice cream will melt and then the
liquid will warm to room temperature.
• This is because nature works to balance heat
energy! Equal energy for all!
Introduction

Question #2

• As the cup of coffee cools,

how is the heat energy moving? Why?
• The heat in the cup of coffee is moving
from the cup of coffee into the air.
This is because heat energy always
moves in the direction from higher
temperatures to a lower temperatures.
Introduction

Question #3
• As ice cream melts, how is
the heat energy moving? Why?
• The heat in the air is moving from the air
into the ice cream.
This is because heat energy always
moves in the direction from higher
temperatures to a lower temperatures.