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Rocky DEM Release 4.3: unmatched for ANSYS CFD integration and fiber modeling

Building upon innovative multi-core and multi-GPU engines, Rocky DEM 4.3 expands its range of multiphysics particle-dynamics simulation with improved integration features and new models. This latest release significantly expands ANSYS CFD–Rocky DEM integration capabilities, increasing speed of the coupled solution. It also introduces a new embedded, advanced coarse grain model (CGM) along with liquid film and liquid bridge representation. Improvements have also been made to the fiber model, including plastic deformation and discrete particle-breakage capabilities.

Dr. André Bakker, Senior Director, Fluids Business Unit, ANSYS, Inc., emphasizes this new standard of product integration:

I am very happy to see the outcome of the multi-year development work done by ESSS to provide a robust coupling between ANSYS CFD and Rocky DEM. ANSYS CFD’s wide variety of multiphase models to approach fluid–particle problems is now extended with accurate particle shape representation for both single and multi-fluid problems. This enables modeling very complex CFD problems involving fibers, fine powders and particles with complex shapes.”

Several other productivity enhancements are present with this new release: unified particle and boundary collision statistics, new contact data visualization features, efficient particle volume initialization, and innovative OpenGL-based ray tracing post-processes for improved coating analysis. These capabilities bring Rocky DEM to an unprecedented level in terms of usage efficiency, accuracy and data analysis.

ANSYS CFD Integration Improvements

General Improvements

An innovative “single-fluid” approach speeds up the CFD–DEM coupled analysis by a factor of three, while new Lagrangian–Eulerian mapping captures sharply and consistently high-concentration liquid–particle interfaces. Users can increase physics fidelity by taking into account turbulence energy within fluid–particle interactions.

Coarse Grain Model (CGM)

Embedded, advanced CGM brings accurate particle scale-up when modeling fluid–particle problems that contain huge numbers of particles through an innovative particle “clustering” approach. Support for both CFD–DEM coupled particle upscaling as well as DEM-only analysis are available.

Two-way fluidized bed model (left) and respective pressure drop comparison (right) for different coarse grain levels

Micaël Boulet, Ph.D. and Numerical Group Lead at Enerkem says:

After several years at Enerkem modeling our biomass energy reactors using traditional Eulerian and Lagrangian approaches, the adoption of Rocky DEM coupled with ANSYS CFD has opened new horizons for our research work. Rocky’s ability to handle large numbers of particles through its native multi-GPU technology, combined with the innovative DEM-based coarse grain model, built on top of a deep integration with the ANSYS CFD solver enables the simulation of our large-scale fluidized bed reactor with the required physics fidelity.”

Liquid Film and Bridge Model

A new liquid film model considers the effects of liquid on a particle’s surface as well as its impact on particle interaction (collision damping, shear forces and adhesion) through liquid bridge representation. Rheological behavior and percolation phenomena can be simulated using this model.

Particles in drum with moisture content

Elias Taye, Ph.D, Breakthrough Technology Group with Mars Wrigley Confectionery, says:

Confection processing within Mars Inc. is very complex. To optimize and understand the physics, we use DEM, CFD, and structural simulation. For example, modeling the Skittles or M&M coating process — in which we must account for dynamic flow of the actual candy shape, interaction between candies, spraying and drying them, and accurately predicting the coating distribution and crystallization growth — is paramount. Rocky DEM coupled with ANSYS CFD captures these phenomena using liquid bridge models, heat and mass transfer. This allows Mars to migrate its process simulation models into a single, integrated and high-productivity workflow, enabling quicker simulations to be done in a much faster response time.”

Plastic Fiber Deformation

Rocky DEM’s new fiber model includes plastic deformation effects, anisotropy and an integrity failure model, which allow users to cover a wider range of fiber materials, in more complex equipment, with higher fidelity.

Discrete Breakage (available for fiber, shell and solid particles)

Hay tedder model with millions of flexible fibers means more accuracy for agriculture industry digital models.

Expanding the unique breakage capabilities of Rocky DEM, release 4.3 brings a new high-fidelity breakage model (discrete breakage). This model capability considers the collision location at the particle’s surface along with its consequent internal stresses, capturing shape-dependent breakage and crack propagation.

Scott Dudley, Chief Engineer at Polaris, says:

In our continuous work for increasing product safety, we use the Rocky DEM advanced fiber model to bring a new level of accuracy when analyzing and studying the effect of debris accumulation within our vehicles.”

Volume Filling Particle Initialization

Users can reduce by orders of magnitude initialization time when particle filling is required through a new “any shape” volume-filling feature. By providing a seed point and total mass, particles are placed side-by-side in a volumetric manner even when modeling high-packing zones, like soil beds.

Unified Particle and Boundary Collision Statistics

The feature-rich intra-particle collision statistics that Rocky DEM users rely on have been expanded for inter-particle and boundaries analysis. Collision frequency, locations, energy levels and losses information are available for all particle–particle and particle–boundaries interactions.

Contact Data Visualization and Post-Processing

Instantaneous contact data can now be visualized and post-processed, both through GUI and API. Thus, users can readily understand and analyze contact “network” in order to improve the whole particle system analysis.

Ray Tracing for Particle Coating Analysis

OpenGL-based post-processing enables fast and accurate ray tracing computation for processes like coating and sand blasting.

Dr. Rakulan Sivanesapillai, Expert Modeling Formulation Processes at Bayer AG, emphasizes the importance of this new release into his existing modeling process:

The ability of Rocky DEM to handle true particle shape, combined with the native support for multi-GPU, has enabled Bayer to model full-scale equipment and processes, providing details from particle level through innovative intra-particle collision statistics functionality, up to the whole system. This allows Bayer to simultaneously optimize both its coating-process efficiency and product quality.”

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