Non-intrusive measurements in fire sprinkler sprays

John F. Widmann; David T. Sheppard; Richard M. Lueptow

doi:10.1023/A:1012727614590

Non-intrusive measurements in fire sprinkler sprays

John F. Widmann^*, David T. Sheppard, Richard M. Lueptow

^*Corresponding author for this work

Mechanical Engineering

Research output: Contribution to journal › Article › peer-review

21 Scopus citations

Abstract

The results of phase Doppler interferometry (PDI) and particle image velocimetry (PIV) measurements to characterize the water sprays produced by fire sprinklers are presented. The large size of the water drops produced by fire sprinklers, and the relatively large coverage area of the spray, present significant challenges when attempting to characterize these sprays. These difficulties are especially relevant when using PDI because large drops and large coverage areas may result in attenuation of the transmitting laser beams. For the fire sprinkler investigated, it was determined that attenuation of the laser beam resulted in over-counting of drops due to burst splitting, a situation in which the Doppler signals from single drops are misinterpreted as being due to multiple drops. This effect was minimized by carefully choosing the operating conditions of the PDI processing electronics. PIV measurements provide velocity profiles that can be used as input for fire dynamics simulations to predict the effect of sprinkler sprays on fires. The results from the PIV measurements show good agreement with the velocity measurements obtained from PDI in the core of the spray, but poorer agreement along the sprinkler axis. The discrepancy was attributed to recirculation zones present in the experimental facility and possible biasing of the PIV measurements towards the larger drops.

Original language	English (US)
Pages (from-to)	297-315
Number of pages	19
Journal	Fire Technology
Volume	37
Issue number	4
DOIs	https://doi.org/10.1023/A:1012727614590
State	Published - Oct 2001

Funding

The authors would like to thank Cary Presser for the use of the PDI system. Also, the contributions of Jacob Goodman and Daniel Landau were invaluable during the PDI measurements. Two of the authors (DTS, RML) would like to acknowledge the financial support of the NIST Fire Research Grants Program.

Keywords

Drop size
Drop velocity
Fire sprinkles
Particle image velocimetry
Phase doppler interferometry
Sprinkler sprays

ASJC Scopus subject areas

General Materials Science
Safety, Risk, Reliability and Quality

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Cite this

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title = "Non-intrusive measurements in fire sprinkler sprays",

abstract = "The results of phase Doppler interferometry (PDI) and particle image velocimetry (PIV) measurements to characterize the water sprays produced by fire sprinklers are presented. The large size of the water drops produced by fire sprinklers, and the relatively large coverage area of the spray, present significant challenges when attempting to characterize these sprays. These difficulties are especially relevant when using PDI because large drops and large coverage areas may result in attenuation of the transmitting laser beams. For the fire sprinkler investigated, it was determined that attenuation of the laser beam resulted in over-counting of drops due to burst splitting, a situation in which the Doppler signals from single drops are misinterpreted as being due to multiple drops. This effect was minimized by carefully choosing the operating conditions of the PDI processing electronics. PIV measurements provide velocity profiles that can be used as input for fire dynamics simulations to predict the effect of sprinkler sprays on fires. The results from the PIV measurements show good agreement with the velocity measurements obtained from PDI in the core of the spray, but poorer agreement along the sprinkler axis. The discrepancy was attributed to recirculation zones present in the experimental facility and possible biasing of the PIV measurements towards the larger drops.",

keywords = "Drop size, Drop velocity, Fire sprinkles, Particle image velocimetry, Phase doppler interferometry, Sprinkler sprays",

author = "Widmann, {John F.} and Sheppard, {David T.} and Lueptow, {Richard M.}",

note = "Funding Information: The authors would like to thank Cary Presser for the use of the PDI system. Also, the contributions of Jacob Goodman and Daniel Landau were invaluable during the PDI measurements. Two of the authors (DTS, RML) would like to acknowledge the financial support of the NIST Fire Research Grants Program.",

year = "2001",

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doi = "10.1023/A:1012727614590",

language = "English (US)",

volume = "37",

pages = "297--315",

journal = "Fire Technology",

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T1 - Non-intrusive measurements in fire sprinkler sprays

AU - Widmann, John F.

AU - Sheppard, David T.

AU - Lueptow, Richard M.

N1 - Funding Information: The authors would like to thank Cary Presser for the use of the PDI system. Also, the contributions of Jacob Goodman and Daniel Landau were invaluable during the PDI measurements. Two of the authors (DTS, RML) would like to acknowledge the financial support of the NIST Fire Research Grants Program.

PY - 2001/10

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N2 - The results of phase Doppler interferometry (PDI) and particle image velocimetry (PIV) measurements to characterize the water sprays produced by fire sprinklers are presented. The large size of the water drops produced by fire sprinklers, and the relatively large coverage area of the spray, present significant challenges when attempting to characterize these sprays. These difficulties are especially relevant when using PDI because large drops and large coverage areas may result in attenuation of the transmitting laser beams. For the fire sprinkler investigated, it was determined that attenuation of the laser beam resulted in over-counting of drops due to burst splitting, a situation in which the Doppler signals from single drops are misinterpreted as being due to multiple drops. This effect was minimized by carefully choosing the operating conditions of the PDI processing electronics. PIV measurements provide velocity profiles that can be used as input for fire dynamics simulations to predict the effect of sprinkler sprays on fires. The results from the PIV measurements show good agreement with the velocity measurements obtained from PDI in the core of the spray, but poorer agreement along the sprinkler axis. The discrepancy was attributed to recirculation zones present in the experimental facility and possible biasing of the PIV measurements towards the larger drops.

AB - The results of phase Doppler interferometry (PDI) and particle image velocimetry (PIV) measurements to characterize the water sprays produced by fire sprinklers are presented. The large size of the water drops produced by fire sprinklers, and the relatively large coverage area of the spray, present significant challenges when attempting to characterize these sprays. These difficulties are especially relevant when using PDI because large drops and large coverage areas may result in attenuation of the transmitting laser beams. For the fire sprinkler investigated, it was determined that attenuation of the laser beam resulted in over-counting of drops due to burst splitting, a situation in which the Doppler signals from single drops are misinterpreted as being due to multiple drops. This effect was minimized by carefully choosing the operating conditions of the PDI processing electronics. PIV measurements provide velocity profiles that can be used as input for fire dynamics simulations to predict the effect of sprinkler sprays on fires. The results from the PIV measurements show good agreement with the velocity measurements obtained from PDI in the core of the spray, but poorer agreement along the sprinkler axis. The discrepancy was attributed to recirculation zones present in the experimental facility and possible biasing of the PIV measurements towards the larger drops.

KW - Drop size

KW - Drop velocity

KW - Fire sprinkles

KW - Particle image velocimetry

KW - Phase doppler interferometry

KW - Sprinkler sprays

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Non-intrusive measurements in fire sprinkler sprays

Abstract

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Keywords

ASJC Scopus subject areas

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