Numerical experiment on shock wave induced drop fragmentation

A numerical shock tube experiment is performed in order to investigate the shock wave induced fragmentation process of fuel drops in a fuel-coolant interaction scenario. For that purpose the two-phase-code DRIX-2D is used. According to the ability of DRIX-2D, a water drop within a vapour environment is considered. The numerical experiment is performed at a rather high pressure level, thus, the system becomes roughly comparable to Theofanous' water-mercury experiment. The numerical results show that an overpressure, nearly double as high as the shock wave amplitude, is induced inside the drop when the shock wave is reflected at the drop surface. This phenomenon ensures from the larger acoustic impedance of the drop material compared with the surrounding fluid. The induced overpressure causes the drop to expand and a mixing between drop- and environment material takes place in the periphery of the drop. In reality, surface tension prevents this simple mixing and fragmentation occurs. (orig.)