XPS® (eXtended Particle Simulation) is a highly efficient CFD-DEM software for the particle processing industry.

This integrated numerical simulation tool perfectly combines the unique product specifications of the GPU-based DEM (Discrete Element Method) solver XPS®, developed by RCPE GmbH, and the multiphase CFD (Computational Fluid Dynamics) solver of AVL FIRE™, developed by AVL List GmbH.

XPS® is thus able to predict not only the behavior of several Millions of solid particles, but also their interaction with surrounding fluid flow in arbitrary complex geometries.

The advantages of using the new, coupled software can be summarized as follows:

  • Being able to predict and understand fluid-granular flow is necessary for many industries, e.g. chemical, pharmaceutical, process, cosmetics, food, oil&gas, plastics, bulk solids or minerals.
  • The coupled software allows faster product and process development, because simulation is faster, safer and, moreover, cheaper than experiments.
  • The computational expense for large amounts of particles (up to 80 Mio.) is low, thanks to the GPU-based massive parallel architecture.



DEM (Discrete Element Method): XPS-DEM (developed by RCPE GmbH)

  • Computation of granular flows based on particle pairs interactions (Newton’s second law of motion)
  • Running on the Graphics Processing Units – GPUs
  • Advantage is a massive code parallelization

CFD (Computational Fluid Dynamics): AVL FIRE™

  • Computation of fluid flow based on Finite-Volume approach (Navier–Stokes equations)
  • Running on the Central Processing Units – CPUs 


  • Working on deskside environment: workstation with multi-CPU + single/multiple GPU
  • Optimized to drastically reduce the computational demand per time-step and the memory consumption
    • The two codes run on separated computing platforms (CPUs and GPUs): the computing performance of each code is not affected by the other
    • Reduced transferred data amount between the DEM and the CFD codes, which depends only on the number of the DEM-cells and not on the number of particles
  • Modular software design: highly extend- and configurable
  • All Nvidia graphic cards from Fermi-architecture on (e.g. also Kepler) are supported. Recommended: Titan X GeForce GTX (12GB, 3072 cores).



  • The GPU (Graphics Processing Unit) is a device that:
    • is a coprocessor to the CPU (Central Processing Unit) or host
    • has its own DRAM (device memory)
    • runs many threads in parallel
  • Data executed as kernels run in parallel on many threads
  • Differences between GPU and CPU threads:
    • GPU threads are extremely lightweight - very little overhead
    • GPU needs 1000’s of threads for full efficiency


  • Fully developed Graphical User Interface (GUI)
  • Handling of complex geometries (STL)
  • Handling of many millions of particles (up to 80 Million on single GPU)
  • Poly-disperse particles
  • Clumps (Multispheres), tablets and capsules
  • Coupled heat exchange between particles and fluid
  • Spray modeling (coating, impregnation, agglomeration, particle growth)
  • Validated DEM and CFD/DEM coupling
  • Advanced post-processing data analysis and conversion (e.g. to Paraview)

XPS_GUI   Paraview_export


Future highlights

  • Capsule shape
  • Convex Polyhedrals shape
  • Usage of different shapes in one simulation
  • Coupling all shapes with CFD
  • Multi – GPU (number of particles > 100 Millions on deskside environment)
  • Particle breakage (both for Multisphere and Polyhedral shapes)
  • Further validation case studies together with Industry and Research Institutions