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Heat transfer from a buoyant smoke layer beneath a ceiling to a sprinkler spray. 1—a tentative theory
Author(s) -
Morgan Howard P.
Publication year - 1979
Publication title -
fire and materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.482
H-Index - 58
eISSN - 1099-1018
pISSN - 0308-0501
DOI - 10.1002/fam.810030106
Subject(s) - smoke , ceiling (cloud) , heat transfer , buoyancy , environmental science , mechanics , drop (telecommunication) , heat load , air entrainment , waste management , meteorology , marine engineering , engineering , mechanical engineering , thermodynamics , structural engineering , physics
A theory is developed for calculating the heat transferred from a buoyant layer of fire gases and smoke, to a sprinkler spray. The theory involves calculating the heat transfer to a single water drop as it describes its trajectory, and uses experimentally derived information on the nature and structure of such sprays to calculate heat transfer to the whole spray. Because such experimental information is sparse for sprinklers, a very simple model of the ballistic properties of a sprinkler spray is adopted. Calculations using the teory suggest that the practive of installing sprinklers in the smoke reservoirs of shopping malls would, in some cases at least, reduce the effectiveness of natural venting of smoke by reducing the buoyancy of the hot smoky gases.