Download user presentations that focus on general applications of FLOW-3D from past users conferences.
Approaches in modeling large-scale granular media flows with FLOW-3D
Donato Rubinetti and Daniel A. Weiss, Institute of Thermal and Fluid Engineering, University of Applied Sciences and Arts Northwestern Switzerland
Granular media flows are present in a variety of industrial and technical engineering applications. Yet the physical behavior of such flows has so far mostly been investigated by experimental observations, and empirical models have been used for their description. Our present study explores possibilities of modeling and numerically solving gas-solid mixtures on the scale of a grain silo using FLOW-3D. Three approaches are investigated: (i) use of the built-in Granular Flow interface, (ii) use of the Sediment Scour model, and (iii) continuum flow by manually increasing the viscosity until the expected mass outflow is met. For the case of an industrially relevant silo geometry, the three approaches are set up and compared, with flour as the granular medium. The computations tend to diverge and/or yield unrealistic results with the Granular Flow and Sediment Scour models. The third model results in a usable solution despite the disputable representation of physical accuracy. The concept presented features a general moving object within the fluid domain to enhance the outflow of the granular medium. In practice it is of utmost importance to determine the forces acting on said object to promote the design of silo geometries by numerical methods. Future studies aim at conceiving of a suitable modeling approach that can be validated by experimental data within the scope of developing tools, to assist in the design of technical applications operating with granular media.
Valentina Virgilli and Roberto Saponelli, Protesa S.p.A
The method of design and production of toilets involves the transfer from the CAD to a real prototype that is optimized through successive changes until the behavior desired by the customer is reached. FLOW-3D was used to avoid the building of a physical prototype through the use of a virtual one, obtained directly from the CAD. The aim of this study is to eliminate most of the laboratory trial period and to speed up tests. The regulation states that, to be operational, a toilet must ensure that the inner surface is completely wetted during the water discharge phase. Through CFD simulation, the discharge channels have been optimized up to the outlet to guarantee the complete cleaning of the toilet’s inner surface. To do this, the first FLOW-3D solution was validated by comparing the results of the analysis with the first prototype performance. Finally, the software IMPROVEit was used to manage the simulation variables and find the optimized solution.
IMPROVEit, a Modern Optimization Engine for FLOW-3D
Raul Niccolò Pirovano, XC Engineering Srl
In the panorama of optimization software and DOE schedulers there is a new tool, designed specifically for FLOW-3D users: IMPROVEit software. IMPROVEit is a very modern and easy-to-use software that performs automated optimization research and regression analysis in a very user-friendly environment. There are several advantages compared to other solutions for CAE users. First, it is a fully automated solver where users do not need to know anything about optimization algorithms. Second, it is ‘budget’ based in the sense that users will enter their available time and the software will achieve the best result within that time. Third, it is optimized for long simulation runtimes and for FLOW-3D users. Regarding FLOW-3D users, the software embeds a “FLOW-3Dsolver” node, an automated “FLOW-3D postprocessing” node to extract the variable of interest, and additional nodes to morph geometries whatever they are: STLs or third-party CAD tools.
Going Against the Grain
Dr. Tony Hirt, Flow Science Founder and Developer Emeritus
Granular materials are ubiquitous. They are important in agriculture (seeds, grains, fertilizers), construction (sand, gravel, cement), pharmaceuticals (pills, powders) and, of course, the environment (debris flow, river and shore deposits, sand dunes, etc.). Most attempts to develop computational models for predicting the behavior of granular material have focused on discrete particle models. The drawback of these approaches is that in practical applications the number of particles is generally in the tens of millions to billions, limiting discrete particle simulations by computer memory and/or computational time. In this presentation, a more efficient continuum model is described that has been implemented in FLOW-3D. Computational results are used to illustrate the complex, and sometimes non-intuitive, behavior of granular materials that exhibit features of both fluids and solids. How does an hour glass work? Why can it be difficult to mix granular materials? Why does a shear flow reduce the settling of granular particles? These questions will be answered using simulations of simple flow situations. Combining simple physical models with guidance from basic experimental studies has resulted in a computational model that is able go up against the errant behavior of dense clouds of interacting grains.
A numerical study on prediction of the permeability of porous media consisting of randomly close packed spheres using FLOW-3D
Shizhao Li, Jon Spangenberg and Jesper Hattel, Technical University of Denmark
A three-dimensional numerical model is proposed to determine the pressure drops in porous media consisting of randomly close packed spheres. The permeability of porous media is calculated using Darcy’s Law, a linear correlation that describes the relationship among permeability, pressure drop across the porous media, fluid viscosity, and superficial fluid velocity. Ensemble averaging is carried out to account for the effects of orientations and spacing on permeability when dealing with random packs. In addition, the effects of grid size, sphere pack size and boundary condition on permeability are investigated to obtain more accurate results. The numerical results agree well with those computed from analytical correlations, such as Kozeny-Carmen and Rumpf-Gupte correlations. Moreover, different types of packing methods are also studied. The permeabilities of monodisperse, monomodal, bidisperse and bimodal spheres are calculated. The effects of the normal distribution in monomodal case, diameter ratio and large-to-total sphere ratio in bidisperse case and bimodal case are also investigated in this study.
Color change of an HDPE extrusion
Emanuele Andalò1, Roberto Saponelli1,2 and Valentina Virgilli1
1Protesa s.p.a., 2Unimore
This study concerns the simulation of an HDPE fluid within an extruder to evaluate the pressure distribution within the channel and the development of stagnation areas. The problem to be solved is the time required to make the color change and move to a different colored plastic. With the original geometry this process is too long and leads to losses of a lot of plastic. In fact, as demonstrated by the tests, the products show defects due to a different coloring of the plastic, up to 30 minutes after the color change has been made. Analyses have been set by inserting a scalar input in the fluid. By following the spread of that scalar input through time, it has been possible to reproduce the observed results and, by making changes to the geometry, achieve a reduction of the color change time by up to 15%. With the optimized design, the outer surfaces of the extruder can be cleaned more quickly and for this reason the new layout has been put into production.
Numerical simulation of dynamic segregation of self-consolidating concrete in L-Box and T-Box test setups using FLOW-3D
Masoud Hosseinpoor1, Kamal H. Khayat2 and Ammar Yahia1
1Université de Sherbrooke, 2Missouri University of Science and Technology
Self-Consolidating Concrete (SCC) has pushed back traditional limits concerning steel bars density and complexity of formwork. Its high fluidity makes it more sensitive to segregation during flow and thereafter at rest. It is essential to develop techniques to predict the flow of SCC during the casting of congested and intricate concrete elements given rheological properties of the concrete, the element geometry, and the selected casting process as input parameters. In this presentation, FLOW-3D was employed to simulate the free-surface flow of SCC in the L-Box and T-Box test apparatuses. These tests evaluate shear induced segregation (dynamic segregation) and passing-ability of SCC. In total, 10 simulations were developed to study the effect of rheology parameters on the flow-ability, dynamic stability, and blocking resistance of SCC, for 6.4s period of flow for L-Box and 12s for T-Box test. The parameters of the modeling included also five plastic viscosity values (10, 17, 25, 38, and 50 Pa.s), 75 Pa yield stress, 2500 kg/m3 fluid and particle density, and 100 Pa shear elasticity modulus. The modeled fluids are considered non-Newtonian Bingham fluids. The suspensions also contain 4.7% volumetric content of 20-mm spherical particles. The calculations are found to be in very good correlations with rheological parameters. As conclusion the most dominant parameter on the shear induced segregation and blocking is the viscosity of the fluid as well as the effect on flow velocity, strain rate and kinetic energy.
Self-priming pumps multiphase transient analysis (liquid-bubbles-solid)
Roberto Da Forno1 and Raul Pirovano2
1MDA srl, 2XC Engineering
Self-priming pumps during the priming phase are characterized by a very complex fluid dynamic behavior, where bubbles, liquid phase and turbine motion are strongly coupled in a highly fragmented flow field. Another concern, after the self-priming phase, is the capability to manage solid bodies inside the flow field. All of these matters can be addressed by FLOW-3D. The presentation will cover the analysis of the transient of self-priming phase and the motion of solid bodies inside the pump impacting against walls and turbine blades. During the self-priming phase the analysis shows the flow field inside the pump volute in full details, in particular liquid and bubble distribution, giving useful suggestions concerning strategies to enhance bubble evacuation. Analysis of the motion of the solid bodies shows the evacuation can be enhanced by using a proper deflector, avoiding the recirculation of solid bodies due to vortex inside the flow field.
Simulation of fresh concrete using the elasto-viscoplastic model (Determination of property parameters for numerical analysis)
Tomohiro Nakamura, Flow Science Japan
Slump tests and L-Flow tests are commonly performed at construction sites in order to survey the flow of fresh concrete and its consistency. So it is ideal to use the result of those tests to determine the elasto-viscoplastic model parameters for numerical simulation of fresh concrete. We will present a way to determine elasto-viscoplastic parameters for numerical simulations of fresh concrete by establishing a correlation between the slump value and elasto-viscoplastic parameters.
Simulation of the flow of self-consolidating concrete in various workability test set-ups
Masoud Hosseinpoor 1, Kamal H. Khayat2, and Ammar Yahia1
1Université de Sherbrooke, 2Missouri University of Science and Technology
Self-Consolidating Concrete (SCC) is a new class of high-performance concrete that can flow and self-consolidate without any external mechanical vibration. SCC can be used to cast congested reinforced structural elements and complex geometry. Due to its high fluidity, SCC is sensitive to segregation at rest as well as blockage and segregation during flow into the formwork. The shear rate characteristics of the various workability tests can be different, therefore, the rheological parameters of the SCC should be adjusted to ensure adequate flow properties and stability. Numerical simulations are required to predict the casting process of SCC, taking into account the rheological measurements, geometry of the element, and selected casting process as input parameters. In this study, FLOW-3Dwas employed to simulate free-surface flow of SCC in various workability test methods, such as Slump Flow, J-Ring, L-Box, V-Funnel, and T-Box tests assuming a Bingham material. The simulations were conducted for SCC mixtures with three different levels of yield stress (15, 60, and 100 Pa) and plastic viscosity (25, 65, and 105 Pa.s) that represent a wide range of rheological properties of SCC. Furthermore, simulations of flow in a modified L-Box setup assuming a Bingham material were conducted. SCC mixtures with different stability levels are prepared and their flow performance is assessed. The concrete is cast in the vertical compartment in the L-box at heights corresponding to 500, 900 and 1100 mm in order to evaluate the effect of gravitational force on the flow profile. The effects of rheological parameters and reinforcing bars on the velocity and strain rate values are presented. On the other hand, the comparison between measured and simulated flow profile indicates good accuracy of the predicted values to describe the flow profile of SCC flowing under gravitational and viscous forces. FLOW-3D simulations are compared also with the Dam-Break Theory model results for Bingham and Herschel-Bulkley fluids.
One-way coupled fluid-structure interactions using FLOW-3DStructure Analysis Interface
Yoshikazu Sato1, Shinichiro Aida1, Yasunori Nemoto2 and Takayuki Tashiro2
1DAINICHI Machine and Engineering Co. Ltd, 2Flow Science Japan
F.SAI (FLOW-3D Structure Analysis Interface) enables you to import fluid pressures, temperature, and wall temperature from a FLOW-3D or FLOW-3D/MP simulation into a Structure analysis packages such as NASTRAN or ABAQUS. This one-way transfer at a fluid-structure interface allows you to investigate the effects of fluid flow in a static or transient structural analysis. The one-way transfer of temperatures or Wall temperature information from a FLOW-3D or FLOW-3D/MPanalysis can be used to determine the temperature distribution on a structure in a thermal analysis or the induced stresses in a structural analysis. In this study, we used FLOW-3D to perform a gravity casting simulation analyzing the fluid flow and the solidification process. We then used F.SAI to pass the fluid temperature data to NX NASTRAN to perform a static structure analysis on the product to analyze the displacements that occur during the solidification process.
Performance, scalability of FLOW-3D/MP on HPC cluster environment
Pak Lui, HPC Advisory Council
FLOW-3D provides CFD simulations solutions for investigating dynamic behavior of liquids and gases that can be applied in many different industrial applications and physical processes. FLOW-3D/MPprovides high efficiency in processing by decomposing the computational domains and distributing the workload among the systems in the HPC cluster environment. With the latest FLOW-3D/MP version 5.0, the hybrid parallelization design which incorporates both MPI and OpenMP architecture for running a parallel distributed job which leads to dramatic increase in cluster scalability. The HPC Advisory Council has performed a deep investigation on FLOW-3D/MP to understand its performance and scaling capabilities using the latest multi-core CPU architecture and high speed network interconnects, such as 10GbE and InfiniBand, in HPC systems. The study presents the performance evaluation and networking profiling results to further understand FLOW-3Ddependencies on the network, system architecture, file system, MPI and OpenMP hybrid, as well as to investigate of underlying communications in the network which has effects on the scalability of FLOW-3D/MP.
Motion curve optimization of intermittent conveyance bottling machine for reducing liquid vibration
Ken’ichi Kanazawa and Ken’ichi Yano; Mie University
Recently, the need to accelerate the operating cycle of bottling machines while maintaining low operation cost has arisen. However, conveying bottles at high speed without spilling the liquids inside requires advanced techniques for vibration suppression control. In this study, we optimize the motion curve for an intermittent conveyance bottling machine by using FLOW-3D to decrease residual vibration at the surface of the liquid.