SKYTHIA: A Universal Multi-Phase Flow Analyzer
Authors: Kolev Nikolay Ivanov 
Published: November 2014

SKYTHIA is a computer code for computational simulation of transient multi-phase flows based on three multi-component velocity fields in a porous structure that may change its geometry in time. The foundation of the computer code SKYTHIA allows applications for mathematical simulation of a variety of processes. From
• two-phase gas-plasma multi-component hydrogen detonation in pipe-network with dissociation of the gases,
• through condensation water-steam shock waves in complex pipe networks,
• gas solution and dissolution in liquids, dissolved gas release from water in pipe network and gas-slug formation and transport,
• pressure wave propagation, piping force computation and risk analysis in conventional island of 1700 MWe power plant including detailed models of the high pressure turbine,
• diesel injection problems,
• particles sedimentation in water,
• turbulent mixing and transport in a nuclear power plant sump,
• termite injection by high pressure steam-hydrogen mixture into air environment, melt-water interaction in postulated SWR 1000 severe accidents, alumina melt jet dropped into a subcooled water, Urania melt jet dropped in water,
• void formation in existing-,
• or future boiling water reactors,
• void fraction and velocity distribution in nuclear reactors with different thermal powers,
• modern steam generator simulation, thermal coupling of multi-phase non-equilibrium three fluid non-homogeneous non-equilibrium flow inside the primary piping systems to complete 3D multi-phase non-equilibrium three fluid non-homogeneous non-equilibrium flow inside secondary systems with cyclones and dryers,
• volume fraction of steam in family of steam generators with different power,
• water velocities and void fraction in flooding reservoir for primary emergency condenser being operating on the secondary site as boiler; thermal coupling of multi-phase non-equilibrium three fluid non-homogeneous flow inside the primary piping systems to complete 3D multi-phase non-equilibrium three fluid non-homogeneous flow inside secondary systems,
• complete system for moisture separation of typical PWR, dynamic performance: multi-phase non-equilibrium three fluid non-homogeneous flow inside the secondary moisture separation system,
• local volume fractions of oxide and sodium liquid as a function of (r, z) in the vertical plane for a fast breeder reactor during melt water interaction; energetic interaction of molten reactor material with liquid sodium in argon environment,
• modern pre-heater (condenser) simulation, thermal coupling of single phase flow inside the primary piping systems to complete 3D multi-phase non-equilibrium three fluid non-homogeneous non-equilibrium condensing flow inside secondary systems, etc.
All this applications demonstrate the capability of single model architecture to handle different material systems, different intensities of interactions, and large variety of the spatial and temporal scales of the simulated processes.
This paper gives brief information about the basic principles used to build SKYTHIA, part of the validation procedure and illustrations of some very complex process simulations.