Pressure limit of hydrogen spontaneous ignition in a T-shaped channel

Abstract

Large eddy simulation Pressure relief device Eddy dissipation concept Detailed chemistry a b s t r a c t This paper describes a large eddy simulation model of hydrogen spontaneous ignition in a T-shaped channel filled with air following an inertial flat burst disk rupture. This is the first time when 3D simulations of the phenomenon are performed and reproduced experimental results by Golub et al. (2010). The eddy dissipation concept with a full hydrogen oxidation in air scheme is applied as a sub-grid scale combustion model to enable use of a comparatively coarse grid to undertake 3D simulations. The renormalization group theory is used for sub-grid scale turbulence modelling. Simulation results are compared against test data on hydrogen release into a T-shaped channel at pressure 1.2e2.9 MPa and helped to explain experimental observations. Transitional phenomena of hydrogen ignition and self-extinction at the lower pressure limit are simulated for a range of storage pressure. It is shown that there is no ignition at storage pressure of 1.35 MPa. Sudden release at pressure 1.65 MPa and 2.43 MPa has a localised spot ignition of a hydrogen-air mixture that quickly self-extinguishes. There is an ignition and development of combustion in a flammable mixture cocoon outside the T-shaped channel only at the highest simulated pressure of 2.9 MPa. Both simulated phenomena, i.e. the initiation of chemical reactions followed by the extinction, and the progressive development of combustion in the T-shape channel and outside, have provided an insight into interpretation of the experimental data. The model can be used as a tool for hydrogen safety engineering in particular for development of innovative pressure relief devices with controlled ignition.

Dynamics of Hydrogen Flame Self-Extinction in a Vented Enclosure

“…3, top left). This implies that spontaneous ignition of a sudden hydrogen release by the diffusion mechanism [3] could be an effective technique to reduce pressure effects and thus negative consequences of unscheduled indoor release of hydrogen. The validity of this safety strategy has to be proved by further research.…”

“…The eddy dissipation concept [1] is exploited for simulation of combustion with a full chemistry scheme, and the renormalization group theory [2] is used for the sub-grid scale modelling of turbulence. A similar approach has been successfully applied recently for the simulation of spontaneous ignition of a sudden hydrogen release in a T-shaped pressure relief device [3]. However, compared to the study of spontaneous ignition the reaction scheme for indoor fire simulations excludes NO x chemistry.…”

“…However, compared to the study of spontaneous ignition the reaction scheme for indoor fire simulations excludes NO x chemistry. Previous work [3] can be considered as an implicit validation of the approach and sub-models in absence of hydrogen indoor fire experiments planned for 2013-2014 within the HyIndoor project (www.hyindoor.eu).…”

Study on noise-vibration coupling characteristics of premixed methane–air flame propagation in a tube with an acoustic absorption material

“…A roadway contains all kinds of corners and branches that directly affect the characteristics of ame propagation. Blanchard, 7 Frolov, 8 Lin 9 and Bragin et al 10 studied the effect of bifurcation types, angle size and complex structure of the roadway on the ame propagation velocity, overpressure, induced ame turbulence and impact ignition in tubes. Generally, a large amount of coal dust is deposited in laneways.…”

Self-ignition of hydrogen–nitrogen mixtures during high-pressure release into air

“…In recent years one could observe an increased interest in hydrogen technologies and safety issues corresponding to them, including uncontrolled ignition during discharge into the air from high-pressure installations. Latest experimental [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] as well numerical [19][20][21][22][23][24] works focus mainly on the detailed description of the self-ignition mechanism according to different initial and boundary conditions including: extension channel geometry: diameter [4][5][6][7]19], length [5][6][7][8][9][10][11][12][13][14][15][16][17][20][21][22], cross-section shape [7,8,18,23] or obstacle presence in front of the hydrogen stream [18,…”