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Flow Through Horizontal Vents as Related to Compartment Fire Environments. September 29, 1990-September 30, 1991.


pdf icon Flow Through Horizontal Vents as Related to Compartment Fire Environments. September 29, 1990-September 30, 1991. (1965 K)
Tan, Q.; Jaluria, Y.

NIST GCR 92-607; 105 p. June 1992.

Sponsor:

National Institute of Standards and Technology, Gaithersburg, MD

Available from:

National Technical Information Service
Order number: PB92-213388

Keywords:

vents; compartment fires; convective flow; fire growth; flow rate; room fires

Abstract:

A detailed investigation has been carried out on the flow exchange through a horizontal vent in a compartment containing a fire. A plexiglass tank with a vented horizontal partition in the middle was constructed to simulate the warmer interior environment due to a fire and the cooler ambient environment by filling the upper and lower compartment with brine and pure water, respectively. Experiments have been carried out on the combined natural and forced convection flow by imposing a pressure difference across the vent. The flow rates through the vent were determined over wide ranges of the governing variables, such as the pressure difference delta P across the opening, density difference delta rho across the opening and the opening length to diameter ratio L/D. The basic characteristics of the flow, particularly whether it is unidirectional or bidirectional, was also studied. Volume flow rates were obtained as functions of the governing parameters in terms of correlating equations, from which quantitative information of the effect of delta P, delta rho and L/D on the flow exchange through the vent can be determined. These results can thus be applied to the modeling of fire growth in vented rooms.