Two-Phase Description of Hydrodynamic Fragmentation Processes Within Thermal Detonation Waves

Abstract

Large-scale vapor explosions are described by thermal detonation waves, proceeding through a fuel-coolant mixture. A two-phase flow model is used for modeling the processes inside a wave. One phase is formed by the drops of melt and the other by the coolant and the fragments. For the interfacial transfer relations between the phases new descriptions are presented, which extend earlier thermal detonation models. The fragmentation behavior can be calculated from two different models, one based on deformation breakup and Taylor instability and another describing fragmentation by stripping of capillary waves induced by shear flow instabilities. In addition to the time development of the fragmented mass, the models give also the actual sizes of the fragments. Results of the fragmentation models are compared with the experiments on hydrodynamic fragmentation of single drops of gallium in water flows. For vapor explosion experiments with tin-water and salt-water systems the detonation cases are determined using the wave stripping model.