PROBLEM 3.24
KNOWN: Representative dimensions and thermal conductivities for the layers of fire-fighters
protective clothing, a turnout coat.
FIND: (a) Thermal circuit representing the turnout coat; tabulate thermal resistances of the layers
and processes

Last Time
Convection heat and mass transfer similarity
Nusselt and Sherwood numbers
Evaporative cooling
Problems with Evaporative Cooling and Other Modes of Heat
Transfer
Let's say that a liquid layer experiences both thermal convection and evaporativ

Announcements
Mid-term reminder
Friday, Nov 7th, in this room
105 min., starting at 6pm and 7pm
If you are taking it at 7pm, either come early to put your name on a list, or contact me via
email
This is important if I do not have confirmation that yo

Lecture 15 Mid-Term Review II: Transient Conduction
and External Convection Heat/Mass Transfer (Lectures 8
to 13)
Lecture 8: Heat Transfer with Variation in Space and
Time
Boundary conditions: a combination of
= 0 (adiabatic) and
=
The solution is the

Last Time
Conduction roadmap
Introduction to convection
Governing equations
Navier-Stokes equations (velocity)
Energy equation (temperature)
Mass transfer equation (species concentrations)
Review of velocity boundary layers
Lecture 10 Convection Bo

Last Time
Transient conduction with spatial variation
The Fourier number
Lecture 9 Conduction Roadmap, Introduction to
Convection (Appendix E, 6.1)
Conduction Roadmap
In the past lectures, we introduced several methods for solving conduction heat trans

Announcements
Homework #1 has been graded
Mean is 25/30
RNG told me to grade problems 3,1,6,5,2,4
So the graded problems were 1, 3 and 6
Since we need to vacate the room quickly after lecture, homeworks will be returned in the discussion
sections
For HW

Last Time
Boundary and initial conditions for the heat equation
Thermal resistance analysis
Lecture 4 (3.1, 3.2, 3.3)
Contact Resistance
Generally we model temperature to be a continuous function in space
Sometimes, however, the temperature difference

Announcements
First homework is due 21:00 tonight (officially)
Unofficially, we'll collect homeworks first thing in the morning on Tuesday, as we need to check out the
dropbox key, so you can take a couple extra hours
Reminder: I have extra office hour

Last Time
Multidimensional steady-state conduction
Shape factors
Dimensionless heat transfer
A brief introduction to numerical methods
What is the most likely approximate value of the
dimensionless heat transfer, , for an unknown shape
a) 1.0
b) 3 108

Last Time
Heat conduction with volumetric heat generation
Volumetric Conduction and the Thermal Resistance Analysis
In the book, it is noted that it is incorrect to apply thermal resistance concepts to
problems with volumetric heat generation
While tha

Announcements
Make sure to register your iClicker on
http:/www1.iclicker.com/
Discussion sections start today
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Relation of Heat Transfer to the First and Second Laws
Fouriers Law
The Heat Equation
The heat equation, with variable properties

Last Time
Introduced basic concepts of heat transfer
Heat flux
Total heat transfer
Conduction
Convection
Radiation
Heat Transfer's relation to the First Law
Convection of cold air around a hot surface is
more efficient (faster) than just conduction (if

Problem 1: Two parallel rectangular surfaces have areas of 100001112 each, and are
close enough to each other that it can be assumed that they form an enclosure. The
surfaces radiate only towards each other. The green surface has 81 = 0.5, T1 =
200K, q1 =

Course Information
Instructor: Pavel P. Popov ([email protected])
Office Hours: TBD @ 1114 Engineering Gateway
Teaching Assistant: Jin Dang
Office Hours: TBD @ 1114 Engineering Gateway
Textbook: Fundamentals of Heat and Mass Transfer, 7th Ed.
by Bergman

Announcements
Reminder mid-term is tonight in this room (1hr 45min)
6-8pm or 7-9pm
If you are taking it 7-9pm, either come 5 min. early, or let me know via email
Lecture 16 Internal Flow: Hydrodynamics and
Thermal Considerations, Laminar Flow in Circul

Announcements
HW#3 due Tuesday at 9pm
HW#4 has been posted
Last homework before the exam, covers the last of the material that will be on the
exam
Since HW#4 covers Friday's lecture as well, it will be due next Wednesday at 9pm
Next week, I'll hold e

PROBLEM 2.50
KNOWN: An electric cable with an insulating sleeve experiences convection with adjoining air and
radiation exchange with large surroundings.
FIND: (a) Verify that prescribed temperature distributions for the cable and insulating sleeve satisf

PROBLEM 1.12
KNOWN: Dimensions and thermal conductivity of food/beverage container. Inner and outer
surface temperatures.
FIND: Heat flux through container wall and total heat load.
SCHEMATIC:
ASSUMPTIONS: (1) Steady-state conditions, (2) Negligible heat

PROBLEM 1.57
KNOWN: Silicon wafer positioned in furnace with top and bottom surfaces exposed to hot and cool
zones, respectively.
FIND: (a) Initial rate of change of the wafer temperature corresponding to the wafer temperature
Tw,i = 300 K, and (b) Steady

Last Time
Radiation exchange between multiple finite surfaces
View factors
Radiative surface resistance
Geometric resistance
Lecture 25 Radiative Heat Exchange I General
Approach (13.3-13.4)
Radiative Exchange Between Multiple Surfaces in an Enclosure

Announcements
HW #8 will be posted by tomorrow morning
Due next Friday evening, but since we can't get the dropbox keys until Monday morning
Last homework for the class
Next week
Monday: practice problems for Radiation
Wed/Fri: review for the final

Announcements
Final exam is on Wednesday, Dec 17th 13:30-15:30 in this room (RH 101)
Homework #7 solutions have been posted
Homework #8
Due this Friday evening, you can turn it in by Monday morning
Solutions will be posted at noon on Monday, no late

Announcements
No evening office hours today
HW #7 due Friday, so there will be evening office hours on Friday
Last Time
Radiation emission and absorption from real surfaces
Kirchoff's law
Grey surfaces
A surface satisfies = if
a) It is in thermodynam

Announcements
Final is Wednesday, Dec 17th, 13:30 15:30
Problem 1: Chapter 8 20pts.
Problem 2: Chapter 9 25pts.
Problem 3: Chapter 12 20pts.
Problem 4: Chapter 13 35pts.
First part of problem 4 will require calculation of view factors, but if you cannot

Announcements
I will be doing both discussion sections today
HW #7 will be posted on Friday
Due next Friday, Dec 5th
Last homework will be due Friday Dec 12th
Final exam is Wed, Dec 17th, 13:30 15:30pm
Any preferences for final exam difficulty?
a) Sa

Last Time
Combined Forced and Free Convection
Introduction to Radiation
In the formula = 1/ ,
the Nusselt numbers for forced and free
convection are added when:
a) The forced and free convection flows are
in the same direction
b) The forced and free con

Announcements
Mid-term will be returned in lecture on Friday
HW#4 will be returned next week
Lecture 18 Laminar and Turbulent Flow in Circular
Pipes, Correlations for Non-Circular Pipes, Heat
Transfer Enhancement, Intro to Free Convection (8.48.7, 9.1)