Integral large scale experiments on hydrogen combustion for severe accident code validation-HYCOM

Flame acceleration and DDT in channels with obstacles: Effect of obstacle spacing

“…It is often measured in detonation experiments and correlates with the theoretical parameter x d [28]. Even though detonation cells do not develop until after DDT occurs, λ is generally used instead of x d in empirical correlations related to the detonation initiation and DDT [6][7][8][9][10][11][12][13][14][15][16][17]. To estimate λ for the model reactive system considered here, we computed detonation propagation in two-dimensional (2D) channels without obstacles.…”

“…The development of the deflagration-to-detonation transition (DDT) in practical systems is a complicated combination of several multiscale physical phenom- Table 1 Input model parameters and computed properties of reaction waves for a stoichiometric hydrogen-air mixture P 0 1 atm Initial pressure T 0 293 K Initial temperature ρ 0 8.7345 × 10 −4 g/cm 3 Initial density γ 1.17 Adiabatic index M 21 g/mol Molecular weight A 6.85 × 10 12 cm 3 /(g s) Pre-exponential factor E a 46.37RT 0 Activation energy q 43.28RT 0 /M Chemical energy release ν 0 = μ 0 = D 0 2.9 × 10 −5 g/(s cm K 0.7 ) Transport constants [4][5][6][7][8][9][10][11][12][13][14][15][16][17]. Today it has become a model for evaluation of fuel safety using laboratory experiments.…”

“…The problem of transition to detonation in channels with obstacles can be solved numerically, providing that simulations include all relevant physical processes and resolve all relevant physical scales. Propagation of turbulent flames in obstructed channels has been modeled previously for subsonic and supersonic deflagration regimes without DDT [16,17]. Shock-flame interactions and DDT in channels without obstacles have also been successfully modeled [19][20][21][22].…”

Assessment of CFD Codes Used in Nuclear Reactor Safety Simulations

“…There have been many applications of compressible CFD solvers to model detonations in large-scale geometries: for example, the RUT experiments from the Kurchatov Institute [40], also some calculations of fast deflagrations in a simplified EPR (European Pressurised Water Reactor) containment were performed in the framework of the 5 th FWP Project HYCOM [41]. Hydrogen deflagration models and CFD codes were also evaluated in the 4 th EU FWP programme HDC [42].…”

R&D on support to ITER safety assessment

“…The evaluation of the propensity of hydrogen premixed flame to accelerate inside the VV is done based on prerequisite experimental criteria, initially developed for PWR conditions [8]. A specific experimental program had been performed by FZK (Germany) to extend these criteria to ITER conditions [9].…”