MMAE 323 Midterm Exam
10 March 2015
Last Name:_ First Name _
Problem 1 In the experimental setup shown in Fig. 1, the specimens A and B are rods 2-cm in diameter. Specimens
A and B are made out of 304 stainless steel with a thermal conductivity of 15.2 W/

2nd integration: T ( x ) =
q ' 2
x + C1 x + C2
2k
Applying the BCs,
BC(1) x=0,
T1 =
q '
0 + C1 0 + C2 ;
2k
T1 = C2
q '
L + C1 = q ' L + kC1 ;
BC(2) qS = k
k
T ( x) =
C1 =
qS q ' L
k
;
q' 2 qS q' L
x +
x + T1
2k
k
Problem 2.2 A slab is insulated on o

MMAE 323 Heat and Mass Transfer
HW 9 Due Thursday, April 30 at the beginning of the class
Problem 9.1 A 0.2 m diameter shallow flat pan with adiabatic sides is filled with water at 1 C is
left outdoors at night. The sky is clear, so that its effective tem

Due Thursday, 26 Feb. 2015
MMAE 325 HW 4
Problem 4.1 An 8-cm-diameter potato ( = 1100 kg/m3, cp = 3900 J/kgK, k = 0.6 W/mK), initially
at a uniform temperature of 25 C, is baked in an oven at 170 C until a temperature sensor inserted to
the center of the

AIAA JOURNAL
Vol. 44, No. 1, January 2006
One-Step Aeroacoustics Simulation
Using Lattice Boltzmann Method
X. M. Li, R. C. K. Leung, and R. M. C. So
Hong Kong Polytechnic University, Hong Kong, Peoples Republic of China
The lattice Boltzmann method (LBM)

Qconduction = kA
dT
T
kA
dn
x
Range: [cm2/s]
metals
0.1 to 1
insulators
0.01 to 0.001
gases
0.2
Range: D[cm2/s]
solids
10-6 to 10-23
liquids
10-4 to 10-7
gases
1 to 10-2
Typical values of h[W/m2-K]
Qconvection = hA(TH TC )
1.6

NAME _
A hot potato with a surface temperature of 375oF
(190.6 C) and emissivity of 0.93 radiates to a large
room with walls at 70oF (21.1 C). To keep the potato
warm, someone covers it loosely with a single layer of
aluminum foil, which has an emissivity

Radiation Heat Transfer
Introduction
Electromagnetic wave spectrum
Thermal radiation: 0.1 m < l <100 m.
Emission depends on T[K] and properties of emitting surface.
E = h =
hc
Plancks const.=6.626 10-34 Js = 4.13610-15 eVs
c= 299,792,458 m/s
MMAE 322 Radi

4. Extended Surfaces; FINS:
Fin temperature to vary only along
the fin length; temperature variation
along other directions is negligible.
This is certainly the case for fins
made of thin metal sheets such as
the fins on a car radiator.
Error involved in

Transient Heat Conduction
1. LUMPED SYSTEM ANALYSIS
Interior temperature of some
bodies remains essentially
uniform at all times during a
heat transfer process.
The temperature of such
bodies can be taken to be a
function of time only, T(t).
Heat transfer

MMAE 323 Final Exam, 2014
Name (print): _
Problem 1. (10 points) Large electrical currents are often carried in aluminum conductors (k_aluminum=190 W/m-K).
Consider a long, 2-cm diameter cable covered by insulation 2-mm thick. For a particular application

MMAE 323
H.W.7
Spring 2015
Problem 7. 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 and cal

Due Thursday, April 2, 2015
MMAE 323 HW 6
Problem 6. 1 Water at 20 C flows over the flat plate at U = 0.5 m/s. The temperature of the plate is
40 C.
a) Find the thickness of the viscous boundary layer 0.5m from the leading edge.
b) Find the thickness T of

Modeling in HT and MT
Approximate
-geometry
-properties
- h
- 1-D .
1
Analogy between HT and transfer of el. charge
(steady state and 1-D).
U E
I=
=
R
R
Q=
T
R
T ( x)
Ohms Law
HT
TH
TL
TH
TL
1.2
1. Plate having thickness L and area A
Q = kA (n )
dT
dn
x=n

THERMODYNAMICS AND HEAT TRANSFER
E = W + Q
Thermodynamics is typicaly concerned with the amount
of (a) heat transfer and (b) work transfer as a system goes
from equilibrium state to another.
Heat Transfer:
Q=?
T= ?
dT
Q = kA
dx
Mass Transfer:
J= ?
C=?

MMAE 323 HW 1
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 the bulb is d=2 cm.
What is the

MMAE 323 HW 4
SOLUTION
Due
Problem 4.1
A hot dog is 12-cm-long and 2 cm in diameter is initially at 5 C. It is placed into water (Tw=100C) while the
heat transfer coefficient is h= 300 W/m2K. The properties of the h

MMAE 323 HW 2
Due Tuesday February 7, 2017
Problem 2.1 The curing of concrete is an exothermic reaction; the curing process produces volumetric
heating. If a concrete slab is thick enough, the temperature can rise to the point where thermal stresses may
c

TRANSIENT HEAT CONDUCTION IN SURFACE LAYERS
or
The SEMI-INFINITE SOLID model
Semi-infinite solid has one single plane surface at x=0, and
extends to infinity in all directions.
For short short enough time, transient in confined to the thin
surface layer (

MMAE 323 Midterm Exam Spring 2017
Last Name: _ First Name_
Problem 1 One method used to determine the thermal conductivity is to sandwich an electric
heater between two identical plates.
Consider two pieces of material A, each piece is 1-cm thick, 10-cm w

MMAE 323 HW 1
Due Monday January 29 2014
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 the b

323 HW 2
Due Wednesday February 5, 2014
ww
Problem 2.1: The plate shown in Fig. 2 has thermal
conductivity k= 10 W/m-K. The boundary conditions are
given in the figure.
a) Derive an expression for T(x) in the plate, as a
function of S W / m2 and other par

Updated solution for HW #4 Problem #2
Resolution done with EES, step by step:
Code:
/ HW #4
/ Problem 2
/ Updated solution G. Bonnavion A. Ostrogorsky
/ Properties:
k=164
rho=8500
c=400
h=400
k_air=0,025
Volume=4/3*pi*(D/2)^3
Area=4*(D/2)^2*pi
/"a) Determ

MMAE 325 HW 3
Thursday Feb. 19, 2015
Probem 3.1
a) Derive the differential fin equation, assuming steady state.
b) Assume that fin is infinite. Apply the appropriate boundary conditions, and solve the
differential equation.
c)
Assume finite fin with insul

MMAE 525
H.W.5
Due March 5, 6:30 PM, 2013
Problem 5.1 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 wo

MMAE 325 HW 5
Due March 2nd 2017
Problem 5.1
Problem 5.2 A thick wood slab (k = 0.17 W/m C and =1.28 x10-7 m2/s) that is initially at
a uniform temperature of 25C is exposed to hot gases at 550C for a period of 5 minutes. The
heat transfer coefficient bet