Name:
EML 4140 Exam 2
Spring 2015
EML 4140 Heat Transfer
Exam 2 Spring 2015
Problem 1 (25 points)
A fluid flows through a pipe with inside diameter D = 0.12 m and length L = 75 m. The flow rate of the
fluid is 0.26 kg/s. The pipe is maintained at a consta
EML 4140 Radiation Heat Transfer
Fall 2011
Time: M W F, Period 2 (8:30 am 9:20 am)
Location: WM 0100
Instructor
Dr. Jrg Petrasch,
Department of Mechanical and Aerospace Engineering
330 MAEB
[email protected]
Name:
EML 4140 Exam 1
Spring 2015
EML 4140 Heat Transfer
Exam 1 Fall 2014
NOTES
If you are using Table 5.1, round up Bi to the nearest number listed in the table do not
interpolate; e.g., if Bi = 0.016 then use values for Bi = 0.02.
In all problems, wri
PROBLENI 5.5
IC‘JO‘WX: Geometries of various objects. Material and-"or properties. Cases {a} through {d}:
Convection heat transfer coefficient between object and surrounding ﬂuid. Case (e): Emissivity of
sphere. initial temperature. and temperature of sur
PROBLEIVI 5.49
KNOWN: Thickness. properties and initial temperature of steel slab. Convection conditions.
FIND: Heating time required to achieve a minimum temperatLu‘e of 550°C in the slab.
SCI-IEMATIC:
Combustion —D T = 800°C _
_._., I100: 250 100le '- ‘
PROBLEII 113
KNOWN: Dimensions and surface temperatures of a flat plate. Velocity and teniperatm'e of air
and water flow parallel to the plate.
FIND: {a} Average convective heat transfer coefficient. convective heat transfer rate. and drag
force when L =
PROBLEl-I 8.10
KNOWN: Thermal energy equation describing laminar. fully developed ﬂow in a circular pipe with
viscous dissipation.
FIND: (a) Left hand side of equation integrated over the pipe volume. viscous dissipation term
integrated over the same volu
PROBLEM 1.47
KNOWN: Dimensions of a milk carton. Temperatures of milk carton and surrounding air.
Convection heat transfer coefficient and surface emissivity.
FIND: Heat transferred to milk carton for durations of 10, 60, and 300 s.
SCHEMATIC:
Tsur
qconv
PROBLEM 2.11
KNOWN: One-dimensional system with prescribed thermal conductivity and thickness.
FIND: Unknowns for various temperature conditions and sketch distribution.
SCHEMATIC:
ASSUMPTIONS: (1) Steady-state conditions, (2) One-dimensional conduction,
PROBLEM 4.62
KNOWN: Nodal temperatures from a steady-state finite-difference analysis for a cylindrical fin of
prescribed diameter, thermal conductivity and convection conditions ( T , h).
FIND: (a) The fin heat rate, qf, and (b) Temperature at node 3, T3
PROBLEM 6.8
KNOWN: Variation of local convection coefficient with x for free convection from a
vertical heated plate.
FIND: Ratio of average to local convection coefficient.
SCHEMATIC:
ANALYSIS: The average coefficient from 0 to x is
1 x
C x -1/4
=
h
dx
x
PROBLEM 5.52
KNOWN: Thickness, initial temperature and properties of steel plate. Convection conditions at both
surfaces.
FIND: Time required to achieve a minimum temperature.
SCHEMATIC:
=7800 kg/m3
cp = 500 J/kg-K
k = 45 W/m-K
Steel plate:
Ti = 300oC
T(0
PROBLEM 7.17
KNOWN: Temperature, pressure and Reynolds number for air flow over a flat plate of uniform
surface temperature.
FIND: (a) Rate of heat transfer from the plate, (b) Rate of heat transfer if air velocity is doubled and
pressure is increased to
PROBLER-l 3.90
KNOW’X: Geometrj.r and boundary conditions of a nuclear fuel element.
FIND: (a) Expression for the temperature distribution in the fuel. {13) Form of temperature
distribution for the entire system.
S CHER-IATIC:
Sfeel—AE
ASSUMPTIONS: (I)
Roger Tran-Son-Tay
EML 4140 - Heat Transfer
Homework 6
HOMEWORK #6
(Due in class on Monday 9th March, 2015)
1. Problem 6.6
2. Problem 6.8
3. Problem 6.13
4. Problem 6.17
5. Problem 6.18
1/1
Roger Tran-Son-Tay
EML 4140 - Heat Transfer
Homework 10
HOMEWORK #10
(Due in class on Friday 17th April, 2015)
1. Problem 12.63
2. Problem 12.75
3. Problem 12.115 (assume that water surface is gray & diffuse)
4. Problem 13.1
5. Problem 13.11
1/1
Roger Tran-Son-Tay
EML 4140 - Heat Transfer
Homework 1
HOMEWORK #1
(Due in class, Friday 16th January, 2015)
1. Problem 1.4
2. Problem 1.27
3. Problem 1.29
4. Problem 1.36
5. Problem 1.45 (omit part c)
1/1
Roger Tran-Son-Tay
EML 4140 - Heat Transfer
Homework 2
HOMEWORK #2
(Due in class, Friday 23rd January, 2015)
1. Problem 2.6
2. Problem 2.10
3. Problem 2.12
4. Problem 2.29
5. Problem 2.47
1/1
Roger Tran-Son-Tay
EML 4140 - Heat Transfer
Homework 3
HOMEWORK #3
(Due in class, Friday 1st February, 2015)
1. Problem 3.2
2. Problem 3.8
3. Problem 3.18
4. Problem 3.27
5. Problem 3.60
1/1
Roger Tran-Son-Tay
EML 4140 - Heat Transfer
Homework 4
HOMEWORK #4
(Due in class, Friday 6th February, 2015)
1. Problem 3.61
2. Problem 3.89
3. Problem 3.114
4. Problem 3.131 (omit part b)
5. Problem 3.159
1/1
PROBLEJI 7.1
KNOW}? Temperature and velocity of ﬂuids in parallel ﬂow over a ﬂat plate.
FIND: [a] Velocity and thermal boundary layer thicknesses at a prescribed distance from the leading
edge. and For each ﬂuid plot the boundaly layer thicknesses as a fu
Heat Transfer Practice Problem 2
Consider a flat plate subject to parallel flow of air on the top with u 6
m
and T 25o C. The
s
surface temperature of the plate is 55o C .Find the average convective heat transfer coefficient and the
rate of heat transfer
Heat Transfer Practice Problem
A 25.4mm x 25.4mm square 2024-T6 aluminum bar of length 20 cm is heated to 400 K in an electric
furnace. The bar is then to be cooled by free convection in either a liquid h 300
W
or in air
m2 K
W
h 10 2
, both at 300
Heat Transfer Exam 2 Spring 2016
NAME:_
Closed book, 2 pages of notes allowed. 50 minute time limit.
1) A 2m x 5m flat plate with a constant surface temperature of 350 K has water at 1 bar and 300 K
flowing over it at 0.1 m/s across the short dimension. F
Heat Transfer Exam 1 Spring 2016
NAME:_
Closed book, 2 pages of notes allowed. 50 minute time limit.
1) A stone ( k = 2 W/m-K) wall of a castle is found to be 1 m thick. If the inside temperature is 20oC and
the outside temperature is -10oC find the heat
PROBLEM 7.6
KNOWN: Velocity and temperature profiles and shear stress-boundary layer thickness
relation for turbulent flow over a flat plate.
FIND: (a) Expressions for hydrodynamic boundary layer thickness and average friction
coefficient, (b) Expressions
PROBLEM 7.29
KNOWN: Dimensions of aluminum heat sink. Temperature and velocity of coolant (water) flow
through the heat sink. Power dissipation of electronic package attached to the heat sink.
FIND: Base temperature of heat sink.
SCHEMATIC:
w1 = 100 mm
S
PROBLEM 6.23
KNOWN: Velocity of water flowing over a flat plate. Length of plate. Variation of local convection
coefficient with x. Water temperature.
FIND: Average convection coefficient for roughness applied over the range 0 xr L.
SCHEMATIC:
u
T
xr
Ts
x
PROBLEM 12.15
KNOWN: Emissive power of a diffuse surface.
FIND: Fraction of emissive power that leaves surface in the directions /4 /2 and 0 .
SCHEMATIC:
ASSUMPTIONS: (1) Diffuse emitting surface.
ANALYSIS: According to Eq. 12.15, the total, hemispherical
PROBLEM 12.52
KNOWN: Area, temperature, irradiation and spectral absorptivity of a surface.
FIND: Absorbed irradiation, emissive power, radiosity and net radiation transfer from the surface.
SCHEMATIC:
ASSUMPTIONS: (1) Opaque, diffuse surface behavior, (2
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ENU 4800, 2015
Due by April 22th
HW #4
1. Questions #1 (15 Points)
In the outer un-restructured region of an LMFBR fuel pin, the fission gases are present as very
small bubble (radius <10). In this form the fission gases can be treated as solid fission pr
ENU-4144
Homework Set #1
Nathan Doerr
1. Determine the capacity factor for this two unit plant for 2016.
24 months total with 20.5 months in energy production
20.5/24 = 85.4%
The capacity factor is 85.4%
2. Provide a cogent discussion of the reason(s) why
ENU-4144
April 1, 2017
Homework Assignment #4
(30) 15. Consider the BWR class materials; develop three objective questions with answers for
the material prior to Auxiliary Systems.
1) The minimum DNBR in any part of the core of a BWR is 1.9, true or false