On Unresolved Mechanisms of Large Scale Deflagrations in Complex Geometries

Dmitriy Makarov, Franck Verbecke, James Keenan, Vladimir Molkov

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The paper describes the numerical study performed in order to identify the credible mechanisms of combustion enhancement during hydrogen-air deflagration in a large-scale complex geometry of a mock-up hydrogen refuelling station. The Very Large Eddy Simulation (VLES) combustion model, developed at the University of Ulster, and accounting currently for four mechanisms affecting turbulent burning velocity (unburned mixture flow turbulence, turbulence generated by flame front itself, fractal nature of turbulent flame, and preferential diffusion) is applied to simulate the experimental deflagration. Under-prediction of recorded maximum overpressures is attributed to other flame acceleration mechanisms, not yet accounted for in the model. Phenomena capable of contributing to the increase of mass burning rate are suggested including Rayleigh-Taylor instability, increase of the flame front area due to vortex-flame interactions, and as yet unidentified behaviour of the fractals sub-model parameters. The simulations of flow acceleration and local pressure dynamics were analysed to scrutinise the assumed mechanisms.
LanguageEnglish
Title of host publicationUnknown Host Publication
Place of PublicationSingapore
Pages93-103
Number of pages1140
DOIs
Publication statusPublished - 1 Apr 2011
EventSixth International Seminar on Fire & Explosion Hazards (FEH6) - Leeds, U.K
Duration: 1 Apr 2011 → …

Conference

ConferenceSixth International Seminar on Fire & Explosion Hazards (FEH6)
Period1/04/11 → …

Fingerprint

geometry
combustion
turbulence
hydrogen
overpressure
large eddy simulation
vortex
air
prediction
simulation
station
parameter
rate

Keywords

  • Hydrogen
  • deflagration
  • large-eddy simulation
  • Rayleigh-Taylor instability
  • vorticity
  • fractals

Cite this

Makarov, Dmitriy ; Verbecke, Franck ; Keenan, James ; Molkov, Vladimir. / On Unresolved Mechanisms of Large Scale Deflagrations in Complex Geometries. Unknown Host Publication. Singapore, 2011. pp. 93-103
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title = "On Unresolved Mechanisms of Large Scale Deflagrations in Complex Geometries",
abstract = "The paper describes the numerical study performed in order to identify the credible mechanisms of combustion enhancement during hydrogen-air deflagration in a large-scale complex geometry of a mock-up hydrogen refuelling station. The Very Large Eddy Simulation (VLES) combustion model, developed at the University of Ulster, and accounting currently for four mechanisms affecting turbulent burning velocity (unburned mixture flow turbulence, turbulence generated by flame front itself, fractal nature of turbulent flame, and preferential diffusion) is applied to simulate the experimental deflagration. Under-prediction of recorded maximum overpressures is attributed to other flame acceleration mechanisms, not yet accounted for in the model. Phenomena capable of contributing to the increase of mass burning rate are suggested including Rayleigh-Taylor instability, increase of the flame front area due to vortex-flame interactions, and as yet unidentified behaviour of the fractals sub-model parameters. The simulations of flow acceleration and local pressure dynamics were analysed to scrutinise the assumed mechanisms.",
keywords = "Hydrogen, deflagration, large-eddy simulation, Rayleigh-Taylor instability, vorticity, fractals",
author = "Dmitriy Makarov and Franck Verbecke and James Keenan and Vladimir Molkov",
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Makarov, D, Verbecke, F, Keenan, J & Molkov, V 2011, On Unresolved Mechanisms of Large Scale Deflagrations in Complex Geometries. in Unknown Host Publication. Singapore, pp. 93-103, Sixth International Seminar on Fire & Explosion Hazards (FEH6), 1/04/11. https://doi.org/10.3850/978-981-08-7724-8_02-02

On Unresolved Mechanisms of Large Scale Deflagrations in Complex Geometries. / Makarov, Dmitriy; Verbecke, Franck; Keenan, James; Molkov, Vladimir.

Unknown Host Publication. Singapore, 2011. p. 93-103.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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N2 - The paper describes the numerical study performed in order to identify the credible mechanisms of combustion enhancement during hydrogen-air deflagration in a large-scale complex geometry of a mock-up hydrogen refuelling station. The Very Large Eddy Simulation (VLES) combustion model, developed at the University of Ulster, and accounting currently for four mechanisms affecting turbulent burning velocity (unburned mixture flow turbulence, turbulence generated by flame front itself, fractal nature of turbulent flame, and preferential diffusion) is applied to simulate the experimental deflagration. Under-prediction of recorded maximum overpressures is attributed to other flame acceleration mechanisms, not yet accounted for in the model. Phenomena capable of contributing to the increase of mass burning rate are suggested including Rayleigh-Taylor instability, increase of the flame front area due to vortex-flame interactions, and as yet unidentified behaviour of the fractals sub-model parameters. The simulations of flow acceleration and local pressure dynamics were analysed to scrutinise the assumed mechanisms.

AB - The paper describes the numerical study performed in order to identify the credible mechanisms of combustion enhancement during hydrogen-air deflagration in a large-scale complex geometry of a mock-up hydrogen refuelling station. The Very Large Eddy Simulation (VLES) combustion model, developed at the University of Ulster, and accounting currently for four mechanisms affecting turbulent burning velocity (unburned mixture flow turbulence, turbulence generated by flame front itself, fractal nature of turbulent flame, and preferential diffusion) is applied to simulate the experimental deflagration. Under-prediction of recorded maximum overpressures is attributed to other flame acceleration mechanisms, not yet accounted for in the model. Phenomena capable of contributing to the increase of mass burning rate are suggested including Rayleigh-Taylor instability, increase of the flame front area due to vortex-flame interactions, and as yet unidentified behaviour of the fractals sub-model parameters. The simulations of flow acceleration and local pressure dynamics were analysed to scrutinise the assumed mechanisms.

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