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Radiation
Configuration Factor - Heat Transfer
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[ Heat
Transfer Table of Contents]
Radiative heat transfer rate between two gray
bodies can be calculated by the equation stated below.
The two separate terms fa
and fe can
be combined and given the symbol f. The heat flow between
two gray bodies can now be determined by the following
equation:
The symbol (f) is a dimensionless factor
sometimes called the radiation
configuration factor,
which takes into account the
emissivity of both bodies and their relative geometry. The
radiation configuration
factor is usually found in a text book for the given
situation. Once the configuration
factor is obtained, the overall net heat flux can be
determined. Radiant heat flux should
only be included in a problem when it is greater than 20% of
the problem.
Example:
Calculate the radiant heat between the floor
(15 ft x 15 ft) of a furnace and the roof, if the
two are located 10 ft apart. The floor and roof temperatures
are 2000°F and 600°F, respectively.
Assume that the floor and the roof have black surfaces.
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