Numerical Validation and Benchmarking of Hydrogen Flame Propagation in a Vertical Acceleration Tube Experimental Facility

During severe accident in a water-cooled nuclear power plant, hydrogen can be generated, leading to risks of possible hydrogen combustion and may threaten containment integrity. In this context, it is important to know the flame speed in a combustible mixture containing hydrogen. The ENACCEF test setup is a vertical acceleration tube with periodic obstacles and a dome of large volume at the top. It is a uniquely designed setup to study flame propagation under severe accident conditions in containment atmosphere. In this work, numerical validation has been carried out for one of the tests conducted at the ENACCEF facility using experimental data available in the open literature. A mechanistic combustion modelling framework especially suitable to fast flame propagation has been evolved and implemented using OpenFOAM. It has been observed that the numerical simulations are able to accurately capture a gamut of observed combustion phenomena like slow deflagrations, flame–turbulence interaction and fast flame acceleration. Moreover, benchmarking with numerical results obtained from other research groups suggests that the present results are more in line with the experimental data. The combined validation and benchmarking studies thus affirm the high fidelity of the adopted modelling approach and its numerical implementation with OpenFOAM.