Effect of Dissolved Gases on Spray Evaporative Cooling With Water.
Effect of Dissolved Gases on Spray Evaporative Cooling
Milke, J. A.; Tinker, S. C.; diMarzo, M.
Fire Technology, Vol. 33, No. 2, Second Quarter,
99-114, May/June 1997.
Sponsor:National Institute of Standards and Technology,
water; evaporation cooling; sprays; solid surfaces; drop
sizes; size distribution; data processing; data
analysis; surface temperature; automatic sprinkler
An experimental investigation of the effect of
nondegassed water used to cool a solid surface is
presented. The solid surface is subjected to thermal
radiant input from three panels positioned above it.
The water is deposited on the surface in the form of a
sparse spray with droplets of about 10 ml. Previous
experiments with degassed water are compared to a new
set of experiments. In addition, the effect of
dissolved gases (air) is quantified in terms of the
overall transient thermal behavior of the solid. A
lower steady-state average temperature is achieved when
gases remain in the water. This result suggests that
the configuration of the liquid droplets on the surface
and the radiant heat input into the droplet are altered
by the gas bubles in the deposited droplet. This
information provides insight into fire control
mechanisms by automatic sprinkler systems.