Page 59 - Mechanical Engineers Reference Book

1/48 Mechanical engineering principles
transfer. Many of these are mainframe or PC packages in Greek letters
which there is integration between design, drawing, manufac-
ture and analysis of stress, vibration, heat transfer, etc. LY thermal diffusivity, absorbtivity
Whenever numerical approximation techniques are used p coefficient of cubical expansion
large-scale analysis leads to considerable demand on data A change in
storage and computing time, which is expensive. It is therefore 9 efficiency
essential to do as much as possible with simple methods before E emissivity
becoming committed to large-scale finite element packages. If h wavelength
it is decided that the use of such a package is necessary it is
vital to be sure of the requirements of the problem, for volume p viscosity
of input data and output results will be large and unpalatable. 4 angle
To assist with this problem, preprocessing packages are used p density, reflectivity
for data input and mesh generation with graphic display, and CT Stefan-Boltzmann constant
post-processing packages are used for graphic display of the 2 summation
results. For example, the temperature distribution in a combu- 0 temperature difference
stion chamber or piston displayed by colour graphics enables 7 transmissivity
easier identification of problem areas.
Finally, it must be emphasized that computing is not a w solid angle
substitute for understanding heat transfer problems. It is an
aid to enable a more detailed investigation to be achieved and
presented in a fashion to enable engineers to improve their
designs.
References

1. Mathesun, J. A. L.. Hyperstatic Structures: an introduction to
the theory of statically indeterminate structures, Butterworths,
1.7.5 Heat transfer: nomenclature London (1971)
2. Meriam, J. L. and Kraige, L. G., Engineering Mechanics,
A area Volume 2, Dynamics, second edition, John Wiley, Chichester
B Biot number (1987)
Specific heat capacity at constant pressure 3. Anvoner, S. Solution of Problems in Mechanics of Machines,
CP Volume 2, Pitman, London (1972)
E; Black-body emissive power 4. Scarborough, J., The Gyroscope: theory and applications,
E; Grey-body emissive power Interscience, New York (1958)
F Fourier number, geometric factor, mean temperature 5 Wilson, W. K., Vibration Engineering:-A practical treatise on
factor the balancing of engines, mechanical vibration and vibration
isolatron, Griffin, London (1959)
g gravitational constant 6. Young, D. and Feglar Jr, R. P., Tables of Characteristic
Gr Grashof number Functions Representing Normal Modes of Vibration of a
h surface heat transfer coefficient Beam. The Universitv of Texas Publication Number 4913
(July 1949)
i+ intensity of radiation in direction 4 7. Cole, E. B., Theory of Vibrations, Crosby Lockwood,
normal intensity of radiation London (1950)
l.h
s' radiosity 8. Thompson, W. T., Theory of Vibrations with Applications,
second edition, George Allen & Unwin, London (1983)
k thermal conductivity 9. Rogers, G. F. C. and Mayhew, Y. R., Engineering
I length Thermodynamics, Work and Heat Transfer, Longman,
m mass, fin parameter Harlow (1986)
rn mass flow rate 10. Bacon, D. H., BASIC Thermodynamics and Heat Transfer,
Butterworths, London (1983)
Nu Nusselt number 11. Kotas, T. J., The Exergy Method of Thermal Plant Analysis,
P perimeter Butterworths, London (1985)
Pr Prandtl number 12. Bejan, A,, Entropy Generation Through Heat and Fluid Flow,
Wiley, Chichester (1982)
Q heat transfer 13. Haywood, R. W., Thermodynamic Tables in SI (Metric)
e heat transfer rate Units, University Press, Cambridge (1976)
Q' heat transfer rate per unit length 14. White, F. M., Heat Transfer, Addison-Wesley, Reading, MA
(1984)
Q heat transfer rate per unit area 15. Ozi$ik, M. N., Heat Transfer, McGraw-Hill, New York
Q "' heat transfer rate per unit volume (1985)
r radius 16. Kreith, F. and Bohn, M. S., Principles of Heat Transfer,
Harper & Row, New York (1986)
Ra Rayleigh number 17. CIBS Guide, Section A3 Thermal properties of building
Re Reynolds number structures; Section A5, Thermal response of buildings,
St Stanton number London (1980)
T temperature 18. Kern, D. Q., Process Heat Transfer, McGraw-Hill, New York
t time 19. (1984)
Bacon, D. H., Basic Heat Transfer, Butterworths, London
U overall heat transfer coefficient per unit area (1989)
U' overall heat transfer coefficient per unit length 20. Adams, J. A. and Rogers, D. F., Computer-aided Heat
Transfer Analysis, McGraw-Hill, New York (1973)
V velocity 21. Myers, G. E., Analytical Methods in Conduction Heat
X,Y,Z rectangular coordinates Transfer, McGraw-Hill, New York (1971)