Water Droplet Evaporation from Radiantly Heated Solids. Final Report. September 1992-May 1994.
Water Droplet Evaporation from Radiantly Heated Solids.
Final Report. September 1992-May 1994.
(4345 K)
Tinker, S. C.; diMarzo, M.
NIST GCR 95-665; 158 p. December 1994.
Sponsor:
National Institute of Standards and Technology,
Gaithersburg, MD
Available from:
National Technical Information Service
Order number: PB95-217147
Keywords:
industrial plants; cooling; drop sizes; droplets;
evaporation; fire research; solid surfaces; sprinkler
systems; water sprays
Abstract:
[Former title: Fire Protection in Large Industrial
Fires] A model describing the configuration of a water
droplet evaporating on the surface of a radiantly heated
semi-infinite solid is developed. A shape factor and
the solid-liquid-vapor contact angle describe the
transient droplet shape, though the initial value of the
latter parameter is found to have a negligible effect on
the droplet's evaporation. The droplet shape model and
a modified radiation heat term are incorporated into a
previously developed computer model to predict the
evaporation of a single droplet on a semi-infinite solid
subjected to radiant heat input. The code predicts
transient temperature profiles that agree well with
experiment. A simplified, closed-form solution for the
prediction of surface temperatures in the vicinity of an
evaporating droplet is used to fit the data produced by
the single droplet model. This closed-form solution
facilitates calculations used in a model for the cooling
of a surface by the evaporation of a sparse spray of
water. The previously collected data base for sparse
spray cooling using degassed water is expanded with a
new set of experiments using water containing dissolved
gases.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899