ИСТИНА

Boiling Liquid Expanding Vapor Explosions are energetic events following total or partial loss of containment, typical of high-pressure vessel bursts. The paper presents an approach to mathematical modeling of rapid expansion of a cloud of superheated liquid, generating pressure waves in the ambient atmosphere. The approach is based upon the assumption of thermodynamic equilibrium between the liquid and vapor phases in the two-phase mixture, with the coupled solution of equations of motion in the two-phase and single-phase zoned. The boundary between the zones is considered as a moving contact discontinuity. The model presented extends the approach developed earlier where the mass fraction of vapor was obtained under assumption that the mixture remains isentropic during its whole evolution. In the current model, on the contrary, the isentropic assumption is not made; rather, a total energy equation is considered in the two-phase zone. The advantages of the extended model are: i) entropy production in the shock waves in the two-phase mixture is taken into account, ii) the initial state can be set up without the all-liquid assumption inherent in the isentropic mode, allowing one to consider bursts of partially filled vessels. Example simulations of spherically symmetric cloud expansion and burst of partially filled vessel are presented.