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The greatest discoveries in the 19th and 20th century, in general, pointed to very similar observations in numerous fields: every quantity that appeared to be continuous was discovered to be discrete. Light consists of photons, matter of atomic and sub-atomic particles, the energy level of electrons consisted of quantas, digital information flows in bits and even hereditary information is transferred in smaller discrete units called genes. Most of the efforts of scientists revolved around building the nature of reality from such discrete elements and their transport. Developing fundamental models for the discrete behavior gave the necessary understanding and the tools to recreate the apparent continuity in the observable phenomenon.

Particulate materials, while consisting of such discrete units or elements, are very common in the chemical and process industry. While designing or troubleshooting such equipment needs and understanding of the bulk behavior of the particles, such reality can be built by using models based on the fundamental behavior of particles. Joseph-Louis Lagrange gave us the framework of looking at flow from a different frame of reference, which was essential in the development of solutions of such discrete flows. Of course, numerous other scientists contributed to this to include a lot of complex physical behaviors such as momentum, mass and energy transfer with surrounding fluid, friction, collision, drag, wetting and cohesion with other particles as well as erosion, and abrasion or boundaries. Deriving from the basis of molecular dynamics, the discrete element method (DEM) has made several advances in recent years to emerge as a prominent numerical analysis method of industrial equipment.

Traditionally, designing particulate processes involved thumb rules and expensive experimentation, leading to processes not fully optimized for maximum life, distribution and efficiency at a low energy usage and cost.

Developments in the last few years have resulted in a solution that is the first in the market to have full integration of flow and particulate modeling from within a single integrated environment. For lean particle flows, Lagrangian modeling methods are available in STAR-CCM+® software while the Discrete Element Model (DEM) handles denser flows. I can hear you mumbling “But why should I care?” If you are a process engineer, you can now use a single tool to simulate realistic, non-spherical particle shapes of varying sizes, accurately model particle motion and contact, utilize compatibility with other advanced physics models and reduce expensive testing, all with a single license and from a single GUI.

Again – Single cost; One GUI; Two solvers-Fully coupled; Compatibility with physics; One solution.

The Lagrangian particle model (LMP) solves discrete phase trajectories through a continua for low particle volume fractions predicting turbulence effect on dispersion where contact mechanics are not important. DEM, on the other hand, accounts for collisions, cohesion, adhesion, custom contacts, particle shapes, granular flow properties and particle-particle interactions. Depending on your application and modeling need, you now have a one-stop tool to better understand particulate flows.

Our customers are already deploying this unique capability and reaping the rewards. I would like to highlight a couple:

  • Coal Milling Projects (CMP): In partnership with Aerotherm, CMP recently maximized the throughput of pulverized coal to their burners while reducing pressure drop using simulation. The lower operating cost of the resulting fan design and the reduced wear from the particles resulted in a 21 percent average throughput improvement and an increase in maximum throughput from 22 TPH to 30 TPH. With this, CMP improved the existing design resulting in improved mill product output, lowered fan resistances, reduced internal wear and air heater leakages and lower power consumption. The DEM-CFD offering in STAR-CCM+ is a boon to process engineers.

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Particle flow simulation in a coal mill classifier with STAR-CCM+ (Image courtesy: Aerotherm)

  • ArcelorMittal: In partnership with Aerotherm, ArcelorMittal reduced erosion by 30 percent in particle separators in their steel plant. By using the DEM technology to create a digital twin of the ash extraction unit in a steel plant, the location and severity of erosion were accurately predicted and the modified design reduced erosion by 30 percent. Here’s what they had to say about the simulation process with STAR-CCM+: “Great potential for reduction in operational and maintenance costs.” – Nico de Klerk, ArcelorMittal

Flow in a cyclone separator (Image courtesy: Aerotherm)

These are just a couple examples showing the benefits of a coupled DEM-CFD and/or the Lagrangian approach to designing particulate flow processes. Taking this one step further, the in-built Design Manager in STAR-CCM+ and HEEDSTM software, our design exploration tool, help engineers use intelligent search algorithms to automatically explore the design space and find better process designs and solutions in a shorter time. Having such tools at your disposal means that there’s never been a better time to be a Process Engineer.

Want to know more about how a DEM-CFD coupled solution in STAR-CCM+ helps predict process performance, reduce risk and energy usage and minimize your operating cost? Watch our webcast on improving operations with a DEM-CFD coupled solution here.

As of STAR-CCM+ version 12.04, you can now model realistic particle shapes with the polyhedral DEM particle capability. You can read more about this here.

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Realistic particle shapes with polyhedral DEM particles

I’ll leave you with my favorite DEM-CFD animation showing particle transport in a conveyor modeled with the DEM capability in STAR-CCM+. Simulation in the Chemical & Process Industry sure has come a long way.

Animation of particles on an industrial conveyor modeled with DEM (Courtesy: Aerotherm)

 

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Matthew Godo
STAR-CCM+ Product Manager
Stephen Ferguson
Marketing Director
James Clement
STAR-CCM+ Product Manager
Joel Davison
Lead Product Manager, STAR-CCM+
Dr Mesh
Meshing Guru
Ravindra Aglave
Director - Chemical Processing
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Director, Product Marketing