Last updated:
5/9/2012

Student
Projects

The projects described here are each simple enough that
they may be assigned to undergraduates taking a first heat transfer
course. They may be implemented using
MS Excel or some other user-friendly computational package. Thorough (4-6 pages) instructions for each of
the first six were included in the first edition of Heat
Transfer Tools and seven of the first eight have been assigned in MAE 314 - Heat and Mass
Transfer. They will all be included
in *Heat Transfer Today* when it is
published in 2013.

1. One-dimensional,
Steady-state Conduction in Composite Systems.

This project studies
steady-state conduction in series/parallel configurations, such as are used in
conventional stud-wall (balloon) residential construction. The discussion includes both
the planar isotherm model and the straight-line heat flux model. A similar insulating arrangement is seen to
the right in this 1950’s photograph of a DC-6 aircraft interior.

2. Mr. Jefferson’s Monticello Problem

This project involves a finite-difference
calculation of transient conduction in a slab subject to a time-varying
convective boundary condition at one surface.
In this case the slab corresponds to a wall of

3.

A 21^{st} century improvement on __and__ thermal resistance in one
package. Slightly under 2% of new homes
built in the

b. International
Solar Energy Conference 2004 Paper

c. Writeup

4. Transient Conduction at the Interface
between Two Materials.

In this project we model a finger touching a hot
material as a, one-dimensional, transient conduction problem. We test flesh-soapstone, flesh-cast iron and
flesh-Space Shuttle tile (shown at right) and compare and contrast the
resulting behavior. The interface
between the flesh and other material provides an interesting numerical
challenge for students, as do the significantly different thermal properties of
the three hot materials. (Write-up)

5. Convective Heat and Mass Transfer from a Runner.

This problem is an
embellishment of the common textbook problem of approximating a runner as a
cylinder in cross-flow. We compute both
the sensible and latent heat transfer as a function of the runner’s speed
relative to the wind, ambient air temperature and relative humidity. The air and water property functions Excel/VBA
workbook makes it a simple matter to test a wide range of parameters
without having to look up all the needed properties (some 11 of them) manually.

6. Transmissivity of
Glass.

Here we use tabulated
spectral values to compute the total transmissivity of regular glass and “Low E” glass to both solar
(short wavelength) and terrestrial radiation.
The required integration is done using Simpson’s 1/3 Rule, and the
resulting values are compared with values obtained using the tabulated
blackbody radiation functions in conjunction with a simple “hat” approximation
of the actual curves seen to the right.

New Projects ready to be included in *Heat Transfer Today*:

7. Mr.
Washington’s Dung Repository.

Here we provide some design
guidance for our first President by solving analytically the one-dimensional,
steady-state conduction equation with volumetric generation. The volumetric heat generation comes from the
composting of manure and other organic matter.
The actual structure at Mount Vernon,

8. Evaporative Cooling of Water
in a *Lister* (or Lyster) Bag.

In this project we approximate
the water-containing, semi-permeable, canvas bag as a “lumped capacitance” and
use standard forced convection correlations for a cylinder in crossflow to find
the sensible and latent heat transfer (the latter associated with evaporation
from the outer surface to the bag).
With this information we predict the temperature-time history of the
water as a function of atmospheric conditions including wind speed, air
temperature and relative humidity. This
project makes extensive use of the air-water
property spreadsheet in HTT.

9. Network analysis for steady-state and transient conduction and for radiative exchange.

This
workbook allows the user to draw resistors (and capacitors) for representing a
thermal system and then apply Excel’s equation solving features to the
resulting equations and plot the solution.
The simple example illustrated here is steady-state conduction in a
Structural Insulated Panel (SIPs) as used in residential construction. The core is expanded polystyrene while the
outer layers are oriented strand board (OSB).
A similar construction using cement rather than OSB for the outer layers
has been proposed for use in earthquake-prone countries such as *Forbes*, June 21, 2004).

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