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On Unresolved Mechanisms of Large Scale Deflagrations in Complex Geometries

Makarov, Dmitriy, Verbecke, Franck, Keenan, James and Molkov, Vladimir (2011) On Unresolved Mechanisms of Large Scale Deflagrations in Complex Geometries. In: Sixth International Seminar on Fire & Explosion Hazards (FEH6), Leeds, U.K. Research Publishing. 1140 pp. [Conference contribution]

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URL: http://rpsonline.com.sg/proceedings/9789810877248/html/978-981-08-7724-8_02-02.php

DOI: 10.3850/978-981-08-7724-8_02-02


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.

Item Type:Conference contribution (Paper)
Keywords:Hydrogen, deflagration, large-eddy simulation, Rayleigh-Taylor instability, vorticity, fractals
Faculties and Schools:Faculty of Art, Design and the Built Environment
Faculty of Art, Design and the Built Environment > School of the Built Environment
Research Institutes and Groups:Built Environment Research Institute
Built Environment Research Institute > Hydrogen Safety Engineering and Research Centre (HySAFER)
ID Code:28763
Deposited By: Mr James Keenan
Deposited On:19 Mar 2014 12:52
Last Modified:05 Nov 2014 13:56

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