Homework 1 Solutions
1. Radioactive wastes are packed in a long, thin-walled cylindrical container. The wastes generate
thermal energy non-uniformly according to the relation
(
( ) ),
where is the local rate of
energy generation per unit volume, is a con

Homework 2 Solutions
1. Two 2 m 1 m plates sandwich an insulating layer. Air is at 30C on the left side, and air at -5C is on
the right side. The two plates and the insulating layer are each 1 cm thick. The thermal conductivity
of the plates and the insul

8/21/15
MCEN3022
Heat Transfer
MWF 8:00 8:50 pm
ECCR 1B40
Instructor: Prof. Jana Milford
Acknowledgments
Many thanks to Professors Julie Steinbrenner
and Je Knutsen for a big hand-up with course
materials!

8/28/15
Heat Transfer
Learning Objectives:
Understand the dimensionality of heat transfer
Understand how the heat conduction equation
is derived from an energy balance on a
differential element
Understand how to simplify the HCE for
common situations

9/2/15
Heat Transfer
Learning Objectives:
Understand the general heat conduction
equation
Specify boundary conditions for heat
conduction problems
Solve the 1-D steady state heat conduction
equation with specified boundary conditions
Announcements
Ho

8/26/15
Heat Transfer
Learning Objectives:
Identify 3 modes of heat transfer
Write expression for heat flow and heat flux
for each mode
Define coefficients required for each
expression
Announcements
Concept inventory due today at noon
Office Hours:
K

9/9/15
Heat Transfer
Learning Objectives:
Solve the 1-D steady state heat equation with
internal heat generation and specified boundary
conditions (Chapter 2)
Understand the concept of thermal resistance
(Chapter 3)
Understand the limited circumstanc

Heat Transfer Homework 11 due Friday 5/4 at 1:00 PM
1. #13.17
2. #13.20
3. Develop one qualitative / conceptual heat transfer question that youd like to see on the final, similar to a tough
clicker question. Any concept weve touched on during the semester

Heat Transfer Homework 10 Solutions
1. A sphere made of polished copper, 1 cm in diameter, is placed in a bucket of water. Assume lumped
capacitance. Choose a reasonable value for material properties, and assume they are independent of T. Estimate
the tim

Heat Transfer Homework 8 Solutions
1. Problem 9.18
Frost layer likely due to stratification of room air (cooler at bottom and warmer at top), causing the heat flux to
be a bit greater at the top than near the bottom, keeping slightly above
.
2. For the mi

Heat Transfer Homework 7 Solutions
1.
A refrigerated milk truck carries 1000 gallons of milk across country at a speed of 65 mph (105 km/h). The air temperature
-6
2
outside is 32C ( = 15.8910 m /s, k = 0.0263 W/m-K, Pr = 0.707). Its roof is essentially f

Heat Transfer Homework 6 Solutions
1.
In wintertime, refineries and other chemical facilities often heat on-site buildings using waste heat from various processes. To accomplish this,
air entering the buildings passes through ventilation ducts containing

Heat Transfer Homework 5 Solutions
1. A sphere of metal alloy is annealed in an oven at a temperature of
= 1000C. The radius of the sphere is = 1 m.
The sphere is initially at a temperature of = 200C. The sphere needs to remain in the oven until 95% of it

Heat Transfer Homework 4 Solutions
1. A cobalt bar with a diameter of 5 cm and an initial temperature of 290 K is placed in a furnace. The furnace
temperature is 1250 K, with a heat transfer coefficient of 75 W/m2-K. How long does it take the center of th

Homework 3 Solutions
1. A 3 ft 3 ft 6 ft commercial oven is designed to cook food at 400 F. The exterior surface temperature of the oven
walls is 120F. The walls of the oven are constructed with a 1/8 layer of stainless steel on the exterior ( = 15 W/mK),