A modeling basis for predicting the initial sprinkler spray

Wu, Di; Guillemin, Delphine; Marshall, André W.

doi:10.1016/j.firesaf.2006.11.007

Cited by 38 publications

(25 citation statements)

References 12 publications

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“…Blum and Ren observed many similarities between atomization measurements taken in realistic sprinkler configurations and canonical impinging jet configurations confirming that the fundamental atomization mechanisms described in Fig. 1 provides an appropriate basis for the Sprinkler Atomization Model (SAM) [2]. The current study focuses on the development and evaluation of SAM based on comparisons with detailed atomization measurements taken in a simplified yet realistic sprinkler configuration.…”

Section: Introductionmentioning

confidence: 81%

“…After the spray is formed, the problem becomes one of a discrete liquid phase in a continuous gas where spray dispersion can be predicted through Lagrangian tracking models available in codes such as FDS [14]. While a summary of SAM is provided in this section, a detailed description can be found in Wu et al [2].…”

Section: Modelmentioning

confidence: 99%

“…The stochastic model ultimately provides distributions for initial drop velocity, size, and location. A detailed discussion on the stochastic model is provided by Wu [2].…”

Section: Breakupmentioning

confidence: 99%

“…These fragments will eventually contract to form spherical drops. A more detailed discussion of these atomization processes can be found in Dombrowski [1], Wu [2] and Ren [3].…”

Section: Introductionmentioning

confidence: 99%

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Quantifying the Initial Spray from Fire Sprinklers

Ren¹,

Blum²,

Zheng³

et al. 2008

Fire Saf. Sci.

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The performance of water-based fire suppression systems is governed largely by the spray discharge characteristics associated with the nozzle geometry and injection conditions. In many nozzle configurations such as sprinklers, this initial spray is produced by injecting a water jet onto an orthogonal deflector, resulting in thin, unstable, radially expanding streams. These streams ultimately disintegrate into a complex population of drops forming the spray. The initial spray is generated in distinct stages, which include sheet formation, sheet breakup, and ligament breakup. A Sprinkler Atomization Model (SAM) has been developed based on these physics to predict the initial drop velocity, location, and size based on the nozzle geometry and injection conditions. The initial spray from a simplified yet realistic sprinkler geometry has been quantified through detailed measurements to provide insight into these atomization processes and to evaluate SAM performance. Flow visualization revealed that the deflector produces a continuous radially expanding stream resulting from the flow directed over the tines and a connected underlying orthogonal stream resulting from the flow through the spaces. The measured and predicted breakup locations and drop sizes follow We -1/3 scaling laws, previously established by other researchers in similar canonical configurations. However, SAM over predicts the volume median drop diameter by as much as 40%, probably due to the absence of models to characterize the orthogonal stream underlying the radially expanding sheet. This orthogonal stream generated by the spaces was measured to consist of nearly 50% of the flow and produces smaller drops than the radially expanding sheet. The detailed breakup mechanisms for this stream are currently being characterized to improve fidelity of the atomization model. INTRODUCTIONAutomatic fire sprinklers are accepted as the fire protection system of choice for a wide variety of applications. To support the development of many types of fire protection systems and the design of fire safe environments, modern engineering practices are currently being established like performance-based design, which requires the prediction of fire behavior using physics-based analytical methods and tools. Despite the simplicity of the basic operating principles for fire sprinklers, the complex physics governing water-based suppression including multi-phase transport processes, flame sheet extinction, and extinction of condensed phase reactions, present profound analytical and modeling challenges. Even the physical mechanisms controlling the sprinkler's simple action to generate a dispersed spray are quite complex and do not yield readily to analysis. Yet, as advanced fire protection engineering practices continue to gain popularity, the need to model fire sprinklers for suppression system and even component analysis is inevitable. In this study, the challenge to characterize the initial spray from sprinklers is addressed to advance understanding of the atomization...

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Section: Introductionmentioning

confidence: 81%

Section: Modelmentioning

confidence: 99%

“…The stochastic model ultimately provides distributions for initial drop velocity, size, and location. A detailed discussion on the stochastic model is provided by Wu [2].…”

Section: Breakupmentioning

confidence: 99%

“…These fragments will eventually contract to form spherical drops. A more detailed discussion of these atomization processes can be found in Dombrowski [1], Wu [2] and Ren [3].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Quantifying the Initial Spray from Fire Sprinklers

Ren¹,

Blum²,

Zheng³

et al. 2008

Fire Saf. Sci.

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show abstract

“…Deluge and sprinkler automatic fire extinguishing, modular installation extinguishing fires, fire trunks, water mist fire extinguishers and water for fire fighting streams sprayed water jets are used to extinguish fires. [5] Water mist cools shields, heat radiation and reduces the oxygen concentration. Water has a high specific heat of vaporization-2256 KJ / kg, when it boils occurs dissipation of heat from the combustion zone.…”

Section: Introductionmentioning

confidence: 99%

Experimental Evaluation the Effectiveness of Water Mist Fire Extinguishing Systems at Oil and Gas Industry

Nyashina¹,

Medvedev²,

Vysokomornaya³

2016

EPJ Web of Conferences

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Abstract. Currently mist water is one of the most promising areas of fire protection. We performed an experimental study of phase transformations drops of water mist (range 50 -500 microns) in motion in a high-temperature (500 -2000 K) typical products of combustion of petroleum products (gasoline, kerosene, acetone, alcohol). We used high speed (the speed of shooting at least 10 5 frames per second) and optical methods of recording streams of liquid and gas medium. We determined the effect of the parameters of the test process (the initial temperature and the initial droplet size) at the rate of evaporation of atomized water under these conditions.

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Automatic Sprinkler System Calculations

Fleming

2016

SFPE Handbook of Fire Protection Engineering

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A modeling basis for predicting the initial sprinkler spray

Cited by 38 publications

References 12 publications

Quantifying the Initial Spray from Fire Sprinklers

Quantifying the Initial Spray from Fire Sprinklers

Experimental Evaluation the Effectiveness of Water Mist Fire Extinguishing Systems at Oil and Gas Industry

Automatic Sprinkler System Calculations

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