MMAE 525
H.W.5
Due April 2, 2012
Problem 5.1 Water (p=80 atm, T = 250 C) flows though a square channel a x a = 10 mm x
10 mm. The velocity is 5 m/s. Calculate the heat transfer coefficient using:
a) the Colburn equation.
b) Assume the channel is smooth an
MMAE 525 Exam 2
March 12. 2012
Last Name:_
Problem 1
(5 points)
Define and give units if applicable:
1. Thickness of thermal BL :
laminar flow_
turbulent flow _
2. Nusselt number= _ _[
3. Thermal diffusivity _[
4. Prandtl Number _[
].
].
].
SOLUTION : see
MMAE 525
H.W.3
Due Feb. 27, 2012
Problem 3.1 We would like to define the desired thermal properties for deck surfaces so that one
will not be burned when walking on the surface after it has been exposed to the sun for a long period
of time. We would like
MMAE 525 Exam 1
February 13, 2012
Name:_
Problem 1 The temperature of the human body is 36.5 C at the core (or arterial blood) level which is
approximately 1 cm away from the skin.
a) Calculate the skin temperature, Tskin, when the body is in 20 C air, wi
MMAE 525
H.W.4
Due March 7 zzzz, 2012
Problem 4. 1 The temperature profile at a location in water flowing over a flat surface is
experimentally measured to be
T = 20 + 80 e800 y
where T is in oC and y in m is the distance measured normal to the surface w
MMAE 525
1. Heat Transfer Resistances
1D
steady state.
dT
Q = kA
dn
1.1
1. Resistances for 1D heat flow; steady state.
Analogy between HT and transfer of el. Charge (Ohms Law)
I=
U
R
T
R
Q=
T1 = TH
kA
1.1 Plate having thickness L and area A
Q = kA( n
MMAE 525
0. Introduction
1.1
Energy, heat transfer and work
starage inf low outlow
=
rate
rate rate
S = I O
I
Energy Conservation
dE
=QW
dt
The conservation laws do not provide
information about T fields and fluxes.
Additional equations such as the
MMAE 525
April 20, 2012
Problem 6.1 " Compute qmax for saturated water at 1 atm on a large flat plate if the plate is located:
a) on earth. The terrestrial gravitational acceleration is g0 = 9.81 m/s2.
b) on the moon, where the gravitational acceleration
Chapter 4
TRANSIENT HEAT CONDUCTION
1.
2.
3.
4.
Lumped systems, Bi<0.1
1D transients in finite solids (plates, cylinders and spheres)
Semiinfinite solids
2D and 3D transients
4.1 LUMPED SYSTEM ANALYSIS, T(t)
A copper ball in air can be
modeled as a lu
2. Fins and Fin Resistances
2.1 Heat exchangers
Liquid
hL, TL
Air
hg, Tg
Tg
TL
Q12 =
Q12 =
T1 T2
1
0.003
1
+
+
500 A 100 A 1010 A
T1 T2
1
L
1
+
+
hL A kA hg A
Q12 =
T1 T2
1
0.003
1
+
+
500 A 100 A 10 (10 A)
Fin model: T(x) only
TC hC
L = 0.1m
L = 0.05m
hH
MMAE 525 HW 3
Monday, Sept. 28, 2015
Problem 3.1 A thermocouple (TC) junction is to be used for temperature measurement of the
gas stream. The convection coefficient between the junction and the gas stream is h = 400
W/m2K. The relevant properties of the
MMAE 525
HW 2 due Monday Sept. 21, 2015
Problem 1.
a) Derive the differential fin equation.
b) Assume that fin is infinite. Apply the appropriate boundary conditions, and solve the differential
equation.
c) Assume finite fin with insulated tip. Apply the
MMAE 525 HW 1
Due Monday, September 14, 2015
Problem 1. A spherical bulb is used in microgravity condition for an
experiment at the International Space Station. It provides underwater
illumination in the large tank of water at T w =20 C. The diameter of
t

Fundamentals of Heat Transfer MMAE 525  01
Time
Where
5:00 to 7:30 PM pm
Instructor:
Days
M
PH 108
Prof. A. G. Ostrogorsky, E1 246; AOstrogo@iit.edu
Office Hours: _Monday _2:00 to 3:00 PM_
Textbook:
E1243 C
Y.A. Cengel, A.J. Ghajar, Heat and Mass tran