LES modelling of an unconfined large-scale hydrogen–air deflagration
- 29 September 2006
- journal article
- conference paper
- Published by IOP Publishing in Journal of Physics D: Applied Physics
- Vol. 39 (20), 4366-4376
- https://doi.org/10.1088/0022-3727/39/20/012
Abstract
This paper describes the large eddy simulation modelling of unconfined large-scale explosions. The simulations are compared with the largest hydrogen-air deflagration experiment in a 20m diameter hemispherical polyethylene shell in the open. Two combustion sub-models, one developed on the basis of the renormalization group (RNG) theory and another derived from the fractal theory, were applied. Both sub-models include a sub-grid scale model of the turbulence generated by flame front itself based on Karlovitz's theory and the observation by Gostintsev et al on a critical distance for transition from laminar to self-similar flame propagation regime. The RNG sub- model employs Yakhot's formula for turbulent premixed flame propagation velocity. The best fit flame propagation dynamics is obtained for the fractal sub- model with a fractal dimension D = 2.22. The fractal sub- model reproduces the experimentally observed flame acceleration during the whole duration of explosion, accurately simulating the negative phase of the pressure wave but overestimating by 50% the positive phase amplitude. The RNG sub- model is closer to the experiment in predicting the positive phase but under-predicts by 30% the negative phase amplitude. Both sub- models simulate experimental flame propagation up to 20m and pressure dynamics up to 80m with reasonable accuracy.Keywords
This publication has 32 references indexed in Scilit:
- Laminar flame velocity determination for H2-air-steam mixtures using the spherical bomb methodJournal de Physique IV, 2002
- Implications of a flame surface density approach to large eddy simulation of premixed turbulent combustionCombustion and Flame, 2001
- Instabilities and flame speeds in large-scale premixed gaseous explosionsPhilosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 1999
- Unconfined deflagrative explosion without turbulence: Experiment and modelJournal of Hazardous Materials, 1993
- Turbulent premixed combustion modelling using fractal geometrySymposium (International) on Combustion, 1991
- The effects of gas explosions in free and partially confined fuel/air mixturesPropellants, Explosives, Pyrotechnics, 1985
- Transition to detonation in a large fuelair cloudCombustion and Flame, 1985
- The mechans of transition from deflagration to detonation in vapor cloud explosionsProgress in Energy and Combustion Science, 1980
- Equation of state of the detonation products of RDXCombustion, Explosion, and Shock Waves, 1966
- GENERAL CIRCULATION EXPERIMENTS WITH THE PRIMITIVE EQUATIONSMonthly Weather Review, 1963