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Numerical study of a fire-driven flow in a narrow cavity

Livkiss, Karlis LU ; Husted, Bjarne P. LU ; Beji, Tarek and van Hees, Patrick LU (2019) In Fire Safety Journal 108.
Abstract

Air cavities and gaps between material layers are common in construction systems, e.g. ventilated façades. Air cavity may provide a pathway for smoke and flame spread in case of fire. Performing physical testing to investigate different systems and fire scenarios is resource demanding. Fire Dynamics Simulator (FDS version 6.7.0) was used to simulate fire driven flow between two parallel vertical walls. Flame heights, thermal impact to the interior wall surface and upward flow velocities were predicted with FDS and compared with experimental results. The fire source was a propane burner with 8 × 391 mm2 gas outlet area. Heat release rates were 6.6 kW and 12.4 kW and the distance between the parallel walls was 40 mm. Two... (More)

Air cavities and gaps between material layers are common in construction systems, e.g. ventilated façades. Air cavity may provide a pathway for smoke and flame spread in case of fire. Performing physical testing to investigate different systems and fire scenarios is resource demanding. Fire Dynamics Simulator (FDS version 6.7.0) was used to simulate fire driven flow between two parallel vertical walls. Flame heights, thermal impact to the interior wall surface and upward flow velocities were predicted with FDS and compared with experimental results. The fire source was a propane burner with 8 × 391 mm2 gas outlet area. Heat release rates were 6.6 kW and 12.4 kW and the distance between the parallel walls was 40 mm. Two different convective heat transfer coefficient sub grid scale models available in FDS were investigated. In this study the cavity width to mesh cell size ratio was equal or above 10, resulting in good predictions of flame heights, upward flow velocities and wall temperatures. 2 mm grid resulted in 25% lower HRR in locations near the burner gas inlet, compared to 4 mm grid, indicating the importance of well resolved gas outlet boundary.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Cavity, CFD, Fire, Fire dynamics simulator FDS, Flame heights, Parallel vertical walls
in
Fire Safety Journal
volume
108
publisher
Elsevier
external identifiers
  • scopus:85067845178
ISSN
0379-7112
DOI
10.1016/j.firesaf.2019.102834
language
English
LU publication?
yes
id
fa874fb7-9bc4-4afa-b570-ba757be4a37b
date added to LUP
2019-07-04 13:18:22
date last changed
2019-09-01 06:25:36
@article{fa874fb7-9bc4-4afa-b570-ba757be4a37b,
  abstract     = {<p>Air cavities and gaps between material layers are common in construction systems, e.g. ventilated façades. Air cavity may provide a pathway for smoke and flame spread in case of fire. Performing physical testing to investigate different systems and fire scenarios is resource demanding. Fire Dynamics Simulator (FDS version 6.7.0) was used to simulate fire driven flow between two parallel vertical walls. Flame heights, thermal impact to the interior wall surface and upward flow velocities were predicted with FDS and compared with experimental results. The fire source was a propane burner with 8 × 391 mm<sup>2</sup> gas outlet area. Heat release rates were 6.6 kW and 12.4 kW and the distance between the parallel walls was 40 mm. Two different convective heat transfer coefficient sub grid scale models available in FDS were investigated. In this study the cavity width to mesh cell size ratio was equal or above 10, resulting in good predictions of flame heights, upward flow velocities and wall temperatures. 2 mm grid resulted in 25% lower HRR in locations near the burner gas inlet, compared to 4 mm grid, indicating the importance of well resolved gas outlet boundary.</p>},
  articleno    = {102834},
  author       = {Livkiss, Karlis and Husted, Bjarne P. and Beji, Tarek and van Hees, Patrick},
  issn         = {0379-7112},
  keyword      = {Cavity,CFD,Fire,Fire dynamics simulator FDS,Flame heights,Parallel vertical walls},
  language     = {eng},
  publisher    = {Elsevier},
  series       = {Fire Safety Journal},
  title        = {Numerical study of a fire-driven flow in a narrow cavity},
  url          = {http://dx.doi.org/10.1016/j.firesaf.2019.102834},
  volume       = {108},
  year         = {2019},
}