DEVELOPMENT OF A 2-DIMENSIONAL HYDROGEN DETONATION ANALYSIS CODE DEVISED TO REDUCE THE NUMERICAL DIFFUSION

Evaluation of thermal and mechanical loads on the containment vessel d ue to combustion of flammable gases is essential for addressing the im portant issues of safety analyses of nuclear power reactors under hypo thesized severe accident conditions. In order to predict flammable gas detonation which is the most severe type of combustion, a two-dimensi onal numerial analysis code COMA has been developed using the explicit finite volume method and non-staggered mesh scheme. A new numerically stable transport calculation method has been devised to facilitate tr eatment of a large pressure discontinuity at; the wave front with the minimum numerical diffusion. The test calculation of detonation propag ation in a square cavity surrounded by walls showed that the calculate d propagation velocity agreed well with the theoretical velocity by Ch apman and Jouguet, and the wave reflection at rigid walls and interact ion of detonation waves could be analyzed. The method was then validat ed through a comparison study with the hydrogen detonation tests in a cylindrical tube performed by NUPEC and BNL. The calculated results ag reed with observed overall effects of hydrogen concentration and initi al temperature on detonation wave propagation velocities.