ME 339 Heat Transfer - Exam 1 Solutions
September 30, 2013
1
Problem 1 (30 points)
Consider steady radial heat transfer in a cladded pipe, as shown. The pipe wall is made of copper. The thermal
conductivity of copper may be taken to be 400 W/mK. The cladd
PROBLEM 12.19
KNOWN: Diameter and temperature of burner. Temperature of ambient air. Burner efficiency.
FIND: (a) Radiation and convection heat rates, and wavelength corresponding to maximum spectral
emission. Rate of electric energy consumption. (b) Effe
ME 339
Heat Transfer
Sample Exam 2
These are problems from old exams. They do not constitute a complete Exam 2.
1. An engineer wishes to design an industrial process to cool water droplets at
T = 90C by
shooting them with a velocity of 10 cm/s into stagna
ME 339
Heat Transfer
Instructor: Prof. Jayathi Murthy
Fall 2012
Lecture 12
In-Class Exercises
Ludwig Prandtl
Father of modern aerodynamics
Published his boundary layer theory in 1904,
revolutionizing fluid mechanics
His student, Theodore von Karman,
im
ME 339
Heat Transfer
Instructor: Prof. Jayathi Murthy
Fall 2012
Lecture 8
Problem 5.22
Given: Furnace wall of carbon steel
initially at Ti=300K.
Exposed to hot furnace gases
Thin ceramic coating on furnace
side with Rt,f = 0.01 m2 K/W. Other
side adiaba
PROBLEM 12.14
KNOWN: Surface area, and emission from area A1. Size and orientation of area A2.
FIND: (a) Irradiation of A2 by A1 for L1 = 1 m, L2 = 0.5 m, (b) Irradiation of A2 over the range 0
L2 10 m.
I1 = 1000 W/m2sr
SCHEMATIC:
A1
x
1
L2 = 0.5 m
2
L1
BASIC EQUATION SHEET
Conservation Laws
.
.
.
.
.
Control Volume Energy Balance: Ein Eout Egen Est ; Est mC p dT
.
dt
.
Surface Energy Balance: Ein Eout 0
Conduction
T
"
; qcond qcond A
x
T
T
T
Heat Flux Vector: q" q" i q" j q" k k
i
j
x
y
z
y
z
x
"
Fou
The University of Texas at Austin
Department of Mechanical Engineering
ME 339
HEAT TRANSFER
Unique #18515
1. COURSE DESCRIPTION
Heat transfer plays a central role in nearly every engineering system or process, and is encountered
routinely in industries as
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ME 339
Heat Transfer
Instructor: Prof. Jayathi Murthy
Fall 2012
Lecture 22: Introduction to Radiation
In-Class Exercises
Problem 12.3
2
Problem 12.14
3
Problem 12.19
4
ME 339
Heat Transfer
Instructor: Prof. Jayathi Murthy
Fall 2012
Lecture 22: Introduction to Radiation
Heat Transfer
Objectives
In this lecture, we will begin to look at radiation heat
transfer. The material is relatively complex, so we will cover
it in fi
ME 339
Heat Transfer
Instructor: Prof. Jayathi Murthy
Fall 2012
Lecture 16: Laminar and Turbulent
Heat Transfer in Pipes
Objectives
In this lecture, we will delve deeper into heat transfer in
pipes, considering both laminar and turbulent flows.
There are
PROBLEM 13.45
KNOWN: Long V-groove machined in an isothermal block.
FIND: Radiant flux leaving the groove to the surroundings and effective emissivity.
SCHEMATIC:
ASSUMPTIONS: (1) Groove surface is diffuse-gray with uniform irradiation and radiosity
distr
Chapter 6: Intro to convection
Boundary Layer Features
Boundary Layers: Physical Features
Velocity Boundary Layer
A consequence of viscous effects
associated with relative motion
between a fluid and a surface.
A region of the flow characterized by
shea
PROBLEM 2.31
KNOWN: Wall thickness, thermal conductivity, temperature distribution, and fluid temperature.
FIND: (a) Surface heat rates and rate of change of wall energy storage per unit area, and (b)
Convection coefficient.
SCHEMATIC:
ASSUMPTIONS: (1) On
The University of Texas at Austin
Department of Mechanical Engineering
ME 339
HEAT TRANSFER
Unique #18060
1. COURSE DESCRIPTION
Heat transfer plays a central role in nearly every engineering system or process, and is encountered
routinely in industries as
PROBLEM 2.16
KNOWN: A rod of constant thermal conductivity k and variable cross-sectional area Ax(x) = Aoeax
where Ao and a are constants.
FIND: (a) Expression for the conduction heat rate, qx(x); use this expression to determine the
temperature distribut
PROBLEM 6.4
KNOWN: Surface temperatures of a steel wall and temperature of water flowing over the
wall.
FIND: (a) Convection coefficient, (b) Temperature gradient in wall and in water at wall
surface.
SCHEMATIC:
ASSUMPTIONS: (1) Steady-state conditions, (