GASFLOW Features

GASFLOW is a parallel multiphase all-speed CFD code that solves the time-dependent, 3D, compressible Navier-Stokes equations using the finite volume method. The fluid-dynamics algorithm is coupled with conjugate heat and mass transfer models to represent walls, floors, ceilings, and other internal structures to describe complex geometries.

A linearized Arbitrary-Lagrangian-Eulerian method is used for approximating the solution to the coupled mass, momentum, and energy conservation equations. The implicit, iterative pressure computation in this method, which uses the efficient linear solvers and pre-conditioners, allows simulations of low Mach number, sub-sonic and supersonic flows without switching the solver.

GASFLOW is a best-estimate tool for predicting dispersion, turbulent mixing, and combustion of reactive gases in confined or semi-confined complex geometries with multiple compartments and internal structures, such as nuclear reactor containments, hydrogen refueling stations, tunnels and parking garages. The code can also model steam condensation and evaporation, heat transfer to walls and internal structures, catalytic recombiner and aerosol behaviors.

An analysis with the GASFLOW code will result in the complete fluid dynamics description of gas species and discrete particle distribution and pressure, and temperature loadings on the walls and internal structures participating in an event. It has been well validated and widely used to perform 3D thermal hydraulic and reactive gas safety analysis in open, semi-confined and confined geometries.

GASFLOW code is featured as:

• Well validated N-S solver valid for all-speed flows, including reactive and non-reactive incompressible flows, low Mach number flows, subsonic flows and supersonic flows in real world problems;
  
• Validated RANS, LES and DNS approaches to model wide range of turbulent flows;
• Validated models for broad combustion regimes, including slow/fast deflagration, jet fires and detonation;
• Validated models for conjugate heat and mass transfer mechanisms, including convective heat transfer, thermal radiation, heat conduction in solid structures and steam condensation/evaporation;
• Verified unique features, such as FAVOR approach, σ criterion and λ criterion used to evaluate the risks of FA and DDT, pre-expansion model for blow-down, sub-grid mass flow rate model and many other sub-grid models which make the 3D CFD simulations in real-scale industrial applications possible;
• Scalable high performance parallel computing for large-scale industrial simulations based on MPI and domain decomposition techniques.