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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Entrainment Process in the Vicinity of Pool Fire under Ventilation Condition

Get access (open in a dialog) DOI: 10.1615/IHTC15.fcv.009377
pages 2955-2964

要約

The entrainment process near a source of pool fire under a ventilation condition was experimentally investigated by using a particle image velocimetry technique with solid particles (spores of lycopodium clavatum, the diameter becomes several ????m in frame). A pool fire settled on the floor of compartment was dealt. The pool diameter and the fuel were 450 mm and ethanol, respectively, which resulted in a turbulent convection plume with optically thin radiation. The compartment was poorly ventilated by a mechanical system with a meager negative pressure. The heat release rate of the pool fire and the oxygen concentration in the compartment decreased for the duration of fire, providing the transition from fully developed to ventilation controlled fire. The transition drastically changed spatial and temporal structures of entrainment of ambient fluid. The fully developed fire generated puffing motions with a specific frequency (???? 2 Hz) reported also by existing studies. On the other hand, the ventilation-controlled pool fire yielded horizontal fluid motions, the frequency of which (???? 0.3 Hz) was low compared with that of puffing motions. Such changes in structures activated entrainment of the ambient fluid.