Hydrogen deflagration simulations under typical containment conditions for nuclear safety

This paper presents the modeling of low-concentration hydrogen deflagrations performed with the recently developed KYLCOM model specially created to perform calculations in large scale domains. Three experiments carried out in THAI facility (performed in the frames of international OECD THAI experimental program) were selected to be analyzed. The tests allow studying lean mixture hydrogen combustion at normal ambient, elevated temperature and superheated and saturated conditions. The experimental conditions considered together with the facility size and shape grant a high relevance degree to the typical NPP containment conditions. The results of the simulations were thoroughly compared with the experimental data, and the comparison was supplemented by the analysis of the combustion regimes taking place in the considered tests. Results of the analysis demonstrated that despite the comparatively small difference in mixture properties, three different combustion regimes can be definitely identified. The simulations of one of the cases required of the modeling of the acoustic–parametric instability which was carefully undertaken.

► Lean H2–air combustion experiments highly relevant to typical NPP simulated. ► Analyzed effect of temperature, concentration of H2, and steam concentration. ► Similar conditions and H2 concentration yielded different combustion regimes. ► Flame instabilities (FIs) were the effect driving divergences. ► Model developed for acoustic FI in simulations. Agreement experiments obtained.