Large-Scale Computational Fluid Dynamics

Through the SIERRA code, developed under the DOE Advanced Scientific Computing program, Sandia is able to leverage cutting-edge computational fluid dynamics (CFD) tools that were originally designed for nuclear-weapons-related problems for use in coal and biomass energy applications. These tools allow large-scale simulations of turbulent reacting flows in complex geometries, with millions of computational elements distributed on massively parallel computational platforms. Capabilities include simulation of high-Reynolds number flows, compressible or incompressible flows, turbulent reacting flows with multiple species and Reynolds-averaged turbulence models, and large eddy simulation.

We can simulate reacting particulate flows that are important in gasification or pyrolysis, such as fuel sprays or entrained coal particle-air mixtures, using a Lagrangian particle-tracking capability we developed for reacting particles; phenomena captured with this tool include chemical reaction, evaporation, and particle radiation, all using scalable parallel algorithms on unstructured computational meshes. We have used this flexible capability for a wide range of application simulations including solid propellant fires, fuel-tank impact, and large-scale wildfires.

SIERRA code capabilities continue to increase and evolve. The breadth of expertise within Sandia has traditionally allowed new computational tools to expand through collaborations between code developers, users, modelers, and experimentalists. New capabilities currently under development include dense multiphase models for reacting flows, moving and deforming mesh techniques, high-Mach number flows, and reacting porous media flows with generalized chemistry. These new tools will continue to increase the role of large-scale CFD simulation in the design and development process for new energy technologies.