PROBLEM 7.24
KNOWN: Plate dimensions and initial temperature. Velocity and temperature of air in parallel flow
over plates.
FIND: Initial rate of heat transfer from plate. Rate of change of plate temp
PROBLEM 3.10
KNOWN: A layer of fatty tissue with fixed inside temperature can experience different
outside convection conditions.
FIND: (a) Ratio of heat loss for different convection conditions, (b)
PROBLEM 1.5
KNOWN: Thermal conductivity and thickness of a wall. Heat flux through wall. Steady-state
conditions.
FIND: Value of temperature gradient in K/m and in C/m.
SCHEMATIC:
k = 2.3 W/mK
qx = 10
Homework # 1 Due in class on Thursday Jan 14, 2016
Given:
1. A sphere of area A, mass m0, specific heat C0, which is initially at a temperature T0.
2. A finite pool of liquid of mass m1, specific heat
Homework # 6 Solution
Due in class Thursday February 25, 2016
7.9
2 m/s
0.2m
10 mm
There are 25 strips, each is 10 mm long. The x positions at the beginning and the end of each
strip can be obtained f
Homework # 8 Solution
Due in class Thursday March 10, 2016
Textbook problems Assume fully developed flow if needed
9.6
Lets estimate the Grashof number: GrL
15.9 106
k 0.0263
gL3T
2
Pr 0.707
For 1m
Homework # 7 Solution
Due in class Thursday March 3, 2016
air 0.005 kg s , Tm ,in 20o C , h 25W m2 K
Circular pipe with D 50 mm, L 3m, m
8.18
c p 1006 J kg K
a) Uniform heat flux q 1000W m2 :
q DLq 4
Homework # 5 Solution
Problem 6.3
Air flow over a heated surface. Normally one would have to solve the convection equation for
the temperature profile, but in this case its already done and given to u
Homework # 4
This is a review before the midterm, so it will involve everything we had learned up to this week.
Since the midterm is coming up next week, I will not ask you to turn in this set of home
Homework # 6
Due in class Thursday February 25, 2016
Textbook problems:
7.9
Part a only. Remember to evaluate properties at the film temperature
1
2
Ts T
7.17
7.39
Parts a and b only
7.49
Part a only
PROBLEM 14.44
KNOWN: Thick plate of pure iron at 1000C subjected to a carburizing process with sudden
exposure to a carbon concentration CC,s at the surface.
FIND: (a) Consider the heat transfer analo
PROBLEM 14.34
KNOWN: Radius of a spherical organism and molar concentration of oxygen at surface. Diffusion
and reaction rate coefficients.
FIND: (a) Radial distribution of O2 concentration, (b) Rate
PROBLEM 14.32
KNOWN: Pressure, temperature and mole fraction of CO in auto exhaust. Diffusion coefficient for
CO in gas mixture. Film thickness and reaction rate coefficient for catalytic surface.
FIN
PROBLEM 14.25
KNOWN: Temperature and pressure of helium stored in a spherical pyrex container of prescribed
diameter and wall thickness.
FIND: Mass rate of helium loss.
SCHEMATIC:
ASSUMPTIONS: (1) Ste
PROBLEM 14.22
KNOWN: Oxygen pressures on opposite sides of a rubber membrane.
FIND: (a) Molar diffusion flux of O2, (b) Molar concentrations of O2 outside the rubber.
SCHEMATIC:
ASSUMPTIONS: (1) One-d
PROBLEM 14.21
KNOWN: Pressure and temperature of hydrogen inside and outside of a circular tube. Diffusivity
and solubility of hydrogen in tube wall of prescribed thickness and diameter.
FIND: Rate of
PROBLEM 14.3
KNOWN: Partial pressures and temperature for a mixture of CO2 and N2.
FIND: Molar concentration, mass density, mole fraction and mass fraction of each species.
SCHEMATIC:
A CO2 , M A = 44
Chapter 11 I Heat Exchangers
Like many real-world situations. the customer hasn't
revealed, or doesn’t know. additional requirements that
would allow you to proceed directly to a ﬁnal conﬁgu—
ration.
Problems
I Problems
to
“.Wwig’w’go‘fFZi.
(itmtluvlion
1.1
1.2
The thermal conductivity of a sheet of rigid, extruded
insulation is reported to be it: 0029 me-K. The
measured temperature difference a
PROBLEM 11.23
KNOWN: Counterflow concentric tube heat exchanger.
FIND: (a) Total heat transfer rate and outlet temperature of the water and (b) Required length.
SCHEMATIC:
ASSUMPTIONS: (1) Negligible
PROBLEM 12.3
KNOWN: Thickness and temperature of aluminum plate. Irradiation. Convection conditions.
Absorptivity and emissivity.
FIND: Radiosity and net radiation heat flux at top plate surface, rate
PROBLEM 8.34
KNOWN: Initial food temperature and mass flow rate. Length of heating and cooling sections in a
food sterilizer. Diameter of sterilizer tube. Time-at-temperature constraint, and constrain
PROBLEM 2.58
KNOWN: Qualitative temperature distributions in two cases.
FIND: For each of two cases, determine which material (A or B) has the higher thermal conductivity,
how the thermal conductivity
PROBLEM 4.13
KNOWN: Electrical heater of cylindrical shape inserted into a hole drilled normal to the
surface of a large block of material with prescribed thermal conductivity.
FIND: Temperature reach