The issue of spontaneous ignition of highly pressurized hydrogen release is of important safety concern, e.g. in the assessment of safety risk and design of safety measures. This paper reports on recent numerical investigation of this phenomenon through releases via a tube using a 5th-order WENO scheme. A mixture-averaged multi-component approach was used for accurate calculation of molecular transport. The auto-ignition and combustion chemistry were accounted for using a 21-step kinetic scheme.
The main objective of this study is an insight into physical phenomena underlying spontaneous ignition of hydrogen at sudden release from high pressure storage and its transition into the sustained jet fire. This paper describes modelling and large eddy simulation (LES) of spontaneous ignition dynamics in a tube with a rupture disk separating high pressure hydrogen storage and the atmosphere. Numerical experiments carried out by a LES model have provided an insight into the physics of the spontaneous ignition phenomenon.
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.
Numerical Study of Spontaneous Ignition of Pressurized Hydrogen Release Through a Length of Tube with Local Contraction
Numerical investigations have been conducted on the effect of the internal geometry of a local contraction on the spontaneous ignition of pressurized hydrogen release through a length of tube using a 5th-order WENO scheme. A mixture-averaged multi-component approach was used for accurate calculation of molecular transport. The auto-ignition and combustion chemistry were accounted for using a 21-step kinetic scheme.
Spontaneous ignition processes due to the high-pressure hydrogen releases into air were investigated both experimentally and theoretically. Such processes reproduce accident scenarios of sudden expansion of pressurized hydrogen into the ambient atmosphere in cases of tube or valve rupture. High-pressure hydrogen releases in the range of initial pressures from 20 to 275 bar and with nozzle diameters of 0.5-4mm have been investigated. Glass tubes and high-speed CCD camera were used for experimental study of self-ignition process.