New modeling power is on its way to FLUENT users, with two major releases to begin shipping simultaneously in mid-1998. Version 4.5 of FLUENT will deliver major technical advances for multiphase modeling and mixing simulation to users of our structured mesh CFD solver. Concurrently, FLUENT Version 5 will combine and extend FLUENT/UNS and RAMPANT 4.2, providing users with an unprecedented ability to handle the toughest CFD problems.

FLUENT/UNS and RAMPANT are combined into a single package in FLUENT 5, giving users seamless success to move between multiple solver choices. FLUENT 4.5 extends modeling capabilities on structured meshes.

Multiphase Flow Modeling Par Excellence

The technology leadership of FLUENT for multiphase modeling has been further strengthened with the release of Version 4.5. First, new solution methods yield substantial improvements in the efficiency and robustness of free surface and Eulerian multiphase calculations. These methods include the Full Elimination Algorithm (FEA), a fully-coupled implicit approach for multiphase transport equations, and more efficient time-marching techniques. Improvements of an order of magnitude in solution time have been observed for some complex problems.

For granular (fluid-solid) multiphase models, like flows in risers and densely packed beds, FLUENT 4.5 includes enhanced physics that result in improved accuracy and a broader range of application. These enhancements include improvements to the treatment of granular temperature, solids pressure, solids bulk viscosity, interphase forces, and boundary conditions.

FLUENT 5 includes a new algebraic slip mixture model for multiphase flows. Color indicates solids volume fraction in this cyclone simulation. Courtesy of Fuller Company

Combustion Modeling Heats Up

Combustion modeling is one of the most extensively enhanced areas in FLUENT 5. Models for coal combustion on unstructured meshes will now match and even exceed the outstanding capability users have enjoyed on structured meshes in FLUENT 4.4. These include extension of the equilibrium PDF model to multiple mixture fractions, an enhanced NO_x model including reburning, soot models, new char burnout models, and enhancements to discrete particle modeling.

For gas phase combustion, FLUENT 5 includes a new premixed turbulent combustion model for more accurate flame front prediction compared to traditional finite -rate approaches. Also included is a flamelet model, for improved modeling of non-equilibrium flame behavior.

Turbulent flow in a dump combustor, predicted using the large eddy simulation (LES) model in FLUENT 5. While computationally expensive, LES shows promise for prediction of highly unsteady flows with dominant turbulent structure. The graphic depicts an isosurface of vorticity.

Advanced Radiation Models

FLUENT 5's new discrete-ordinates radiation model handles radiation in transparent and semi-transparent media, specular effects, anisotropic scattering, and non-gray (spectral band) effects. Many new applications can be addressed including specular and transmissive radiation effects in glass processing and light bulbs, and accurate radiation modeling in participating media (such as furnaces and combustors).

Prediction of temperature distribution in an automotive headlamp using the discrete-ordinates model

And Much, Much More

Other improvements in FLUENT 5 include a greatly expanded user function library so that users can customize models. For turbomachinery applications, real gas modeling and a mixing-plane model have been added. Rotor craft can now be simulated using a new blade momentum source model. New turbulence models include the Spalart-Allmaras eddy-viscosity transport model, an economical model with a good track record for external aerodynamics applications.

FLUENT 5's new blade momentum source model approximates time-averaged forces due to rotor motion. The model can also be used to analyze the flow around propeller-driven aircraft and marine vehicles.

FluentNEWS