Water Penetration Ratio Of A Sprinkler Water Spray

作者: W.K. Chow , Victor M.K. Wong

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摘要: The 'water penetration ratio' of a sprinkler spray was studied in this paper. Experiments were conducted inside fire chamber size 4m x 2.96m and height 2.9m. A discharged water collected 120 positions at the floor level. Wood cribs burnt to provide growing plume. collection rates with without measured determine ratio. Results kind are useful for both improving design sprinklers validating field models. INTRODUCTION 0) Automatic systems commonly installed buildings control. From statistical record, it can excellent protection building properties human life. When is actuated, (2}(1l controlled by least three mechanisms , singly or combined: (l) cooling combustion products room reduce thermal feedback combustible elements; (2) direct contact droplets burning material prevent further generation vapor fuel; (3) prewet ting spread. Associated first mechanism two other effects: (l ) inerting gas mixture theevaporated water; displacement large volume air from steam. However, estimated that actual flow rate required extinguish only one-third one sixth normal given surface radiation flux 8 W/cm2• main reason why larger needed because not (1)-0 all nozzle reach lower level . Therefore, effectiveness system highly reduced. most important part head. It be regarded as thermally actuated valve an orifice detlection plates. Water would strike deflection plate form composing different sizes. These expected objects surroundings. them combustibles their terminal velocities might less than upward plume velocity(1·I1). Evaporative mass loss while traveling through smoke layer another possibility but effect obvious when very small(6). This paper presents experimental study on phenomenon. following section describes ratio self-developed set-up. then followed description experiments performed sprinklered wood crib fires. presented ends last conclusion. WATER PENETRATION RATIO Physically'0the amount which able penetrate (1),(9) • act described "penetration ratio" : V Penetration Ratio = V. 100% I

参考文章(2)
Dougal Drysdale, An Introduction to Fire Dynamics ,(1998)
Richard S. Magee, Rolf D. Reitz, Extinguishment of radiation augmented plastic fires by water sprays Symposium (International) on Combustion. ,vol. 15, pp. 337- 347 ,(1975) , 10.1016/S0082-0784(75)80309-2