english | Kontakt | Impressum Auf Erfolgskurs mit dem Research Center Pharmaceutical Engineering ÜBER UNS LEISTUNGSANGEBOT PORTFOLIO NEWS & MEDIA KONTAKT PORTFOLIO Area I Area II Area III IPROCOM Output Beiträge in Fachzeitschriften Patente Akademische Arbeiten Scientific Highlights Auftragsforschung COMBINING CFD AND DEM [News vom: 29.01.2013] In recent years Discrete Element Model (DEM) simulations have increasingly been used to study flows of granular systems. In these simulations the interaction between the solid and the fluid phase is typically neglected and only particle-particle contacts are considered. However, in the pharmaceutical and other industries, fine granular materials are encountered (typically in the order of ten to several hundred microns), where both particle-particle interactions and fluid drag have significant contributions. Examples include fluid-bed drying, hopper filling/discharge, chute flows or die filling. Thus, accounting for fluid-particle interaction is necessary to correctly describe such processes, and to design and to scale-up industrial devices. Combining Computational Fluid Dynamics (CFD) and Discrete Element Model (DEM) makes it possible to simulate fluidic-granular systems. In DEM, the motion of discrete particles is tracked by solving Newton’s second law of motion and in CFD, the flow of a continuum fluid is simulated by solving the Navier–Stokes equations, based on the concept of local averaging. The main advantage of CFD–DEM is that detailed particle-scale information is obtained, including particle trajectories and forces acting on individual particles. Such information cannot be obtained in detail with the alternative method, such as the Two-Fluid Model (TFM) or most experimental techniques. DEM simulations are computationally expensive, and their routine application is still limited to the analysis of several hundred thousand particles. However, the computational performance of DEM simulations can be significantly improved by the newly available Compute United Device Architecture (CUDA) technology. A combination of CFD, executed on the Central Processing Units (CPUs), and DEM, executed on GPUs, is a promising high-performance method for coupled CFD-DEM simulations with up to 9 million particles per GB of GPU-Memory. In our current work, a coupling between the CFD code (AVL-Fire®) and our high-performance GPU-based DEM code was established based on the newly available Compute United Device Architecture (CUDA) technology. The DEM code can simulate many millions of particles on readily available hardware, and the simulations may directly be visualized via a GUI using OpenGL display features. Data exchange between the codes was performed using AVL Code Coupling Interface (ACCI), a software component for co-simulations with an arbitrary number of instances of different simulation programs. Under this protocol the codes concurrently simulate the same time interval and continuously exchange information. The numerical results obtained in this work were validated against experimental and reference CFD-DEM simulation. The advantages of the presented CFD-DEM coupled simulation can be summarized as follows: the two codes run on separated computing platforms (CPUs and GPUs), and therefore, the computing performance of each code is not affected by the other. CUDA technology already allows efficient DEM-simulations including tens of millions of particles without expensive high-performance computing platforms. Our coupling method is more efficient than other approaches and has less memory requirements due to a 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. The figure above shows snapshot of a successfully realized triple-spout fluid-bed simulation including 25 million of particles at the time of 1.0s after start of fluidization and a glass particle size of 0.48mm. zurück Research Center Pharmaceutical Engineering GmbH Inffeldgasse 13 A-8010 Graz Tel: +43(0)316 873-30901 Fax: +43(0)316 873-1030901 Email: office@rcpe.at Website by Werbeagentur Rubikon