Lester Dabu and Lyndon Smith
MEM 345
Dr. Cho
June 1, 2017
The emissivity of a window refers to its tendency to radiate absorbed heat, which is one
of the three methods by which heat is transferred. When solar energy or sunlight, hits an noncoated window,
NEEM 345 Heat Transfer Midterm #1 4—24—14 Name, y (:1 i 0
Z ’ 1 Consider a small copper sphere of diameter 1 cm with a constant heat generation rate
/0 of 20 000 000 W/ms. The initial temperature of the copper sphere 1s 400° C which IS
*
MEM 345 Heat Transfer Special Assignment Radiation Chapter 12
Hard copy of onepage report should be submitted in class, due May 5, 2016 Thursday.
Two students can work together.
Spectral emissive power
1. Objective is to produce a graph of the spectral em
Example 3.6 (7th ed p.138) Critical Insulation Thickness (6th ed Example 3.5)
(due date April 19, 2016 - Tuesday)
Using the numbers in the example, plot q (heat loss from pipe to the surroundings) over a
range of insulation thickness from zero to 4 cm. As
" lVIEM 345 Heat Transfer Midterm #1 4—24—14 Name: )4 ”Q
l. A metal pipe is used to transport steam in a room for which the air temperature is 25°C. Neglect
the radiation heat transfer.
Given: Steam temperature = 486 K = 213°C; Tair = 25°C; hsteam (at i
MEM345 The 5th Bonus Problem (total 30 points) Radiation problem (chapter 13)
Due date May 24, 2016 (Tuesday)
Thermal Equilibrium Temperature
Consider a primary shield having a conical shape with cone angle of 30 degrees, which is
considered as the primar
MEM345 The 4th Bonus Problem (total 30 points) Radiation problem (chapter 12)
Due date May 17, 2016 (Tuesday)
1 WTC Building at New York has glass windowpanes that are specially coated to let light
in and keep heat out. Please explain the basic concept of
Abdulhameed Abdal
MEM 345
May 12, 2016
Bonus
World Trade Center Building at New York has glass window panels that are specially
coated to let light in and keep heat out. This type of coat is Viracon Low E-insulating
W
glass, VRE 15-54. As given that the s
5/26/16
Review: How to find mean fluid velocity in pipe flow?
How to find the mean temperature in pipe flow?
Why cant we use the same method as in um?
Discussion
5/26/16
Mean%Quan(es%(cont.)%
Mean temperature
Hence,
Tm =
2
Tm =
2
um ro
A uc pT dAc
c
! p
MEM345 Recitation Quiz Week 5
Stefan- Boltzmann
E, = (IT; E 60'7"4
Radiation thermal energy transfer [W]:
Wien s displacement law: Amax-
OOoo
. \=tr~b2 macho: regisn
Inn 7': 289311m-K
\
f
l 7"
A [5830K
/ zooox \
is" it! '
:
a) Using the spectral emiss
MEM34S Recitation Quiz Week 7 [ch6] Name
0
Determine the convective heat transfer coefc
" z 95 kW/mz
ill
. Airy
V: 160 mis
Ta, = 115060
a>
->
-)~
Original
conditions
For a flow over a flat plate: q: hA(Twa11 Tf1uid) - kA
%) =qu - Area
wall
lent h on the
noxVxN. v. - W /-/ . QM? \ 1t. 1. \
MEM345 Recitation Quiz #6; Week 9 (Convection Chapters 68) Name _
/(.
TABLE .316 Thermophysical Properties of Saturated Water ( I. V
gamxwwmmummwmwamuwcansax.Wwwwxwtmmva:uamvmm , L gm _ Wmmgfw
Speci Heat 0f Speci Therm
MEM 345 The third bonus problem (total 30 points) Quenching problem (chapter 5)
Due date April 28, 2016 (Thursday)
Consider a small copper sphere of diameter 1 cm with a constant heat generation rate of
30,000,000 W/m3. The initial temperature of the copp
5/17/16
Example: Air flow over a flat plate
< 5x105, So, Laminar flow
1
5/17/16
Example: Air flow over a flat plate
2
5/17/16
Example 7.1
Objective
To find cooling rate of the plate
needed to maintain the plate
at 27oC.
Note air pressure is very low.
Exam