Citation

Nam S. Fire Safety J. 1999; 32(4): 307-329.

Copyright

(Copyright © 1999, Elsevier Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Computational models have been utilized to investigate the penetration capability of sprinkler sprays directly above a fire source with respect to water flow rate, spray drop size, and spray momentum. The spray models are generated by assigning a representative drop size, mass flow rate, discharge speed, and discharge angle for each of 275 trajectories in such a way that they produce computed results which match the measured water flux distribution and spray momentum in the absence of a fire. The spray/fire plume interaction models are created by combining the spray models using a Lagrangian particle tracking scheme with free-burn fire plume models. Actual delivered densities and penetration ratios are computed through the interaction simulations at six flow rates, three fire sizes, and two ceiling heights. Drop sizes and spray momentum at two flow rates are increased by 25 and 50% from the original values without changing the other spray characteristics in order to investigate the effects of each parameter on penetration capability independently. The study indicates that there is an optimal flow rate for a given sprinkler that gives the highest penetration ratio within a practical flow range. It is also shown that increasing drop size is a much more effective way for obtaining a higher penetration ratio compared to increasing spray momentum.