1,720,965 research outputs found
A method for advanced stochastic generation of particles in granular flow simulations and its practical applications in industry
No full textA parametric approach to the generation of multidisperse granular flows for particle simulations
No full textMulti-Body Granular Flow Simulation For The Design and Operation Of Mechanical Separation Processes For Recycling
No full textProducts and material mixtures found in E-waste are highly inhomogeneous and in continuous evolutions. In spite of this variability, state-of-the-art mechanical recycling systems are extremely rigid, both in their design and parameter settings. This is mainly due to the lack of knowledge-based engineering models and tools to support the design and operation of separation processes able to capture, with an acceptable level of confidence, all the major phenomena affecting the quality of the output, including particle-particle interactions and impacts. In this paper, multi-body granular flow simulation is proposed as a modeling and analysis tool able to capture the physics of mechanical separation processes and to support process parameter design, operation and control in industrial settings. The proposed models are validated at pilot plant level. The major improvements towards state-of-the-art modeling approaches are discussed
Model of a Microfluidic Thermal Cycler Activated by Means of Electro-Osmotic Micro-Pumps
No full textA microfluidic thermal cycler for Polymerase Chain Reaction (PCR) has been modeled. A microliter sample is driven along the microchannel by a flow generated by means of electroosmotic micropumps, activated in sequence. Several multichannel pumps configurations have been separately modeled and the efficiency of each device has been evaluated with regard to the effective flowrate and the back flowrate.
Results from these simulations have been then used to define the boundaries for the model of the entire device
Granular Flow Simulation for the Design and Operation of De-manufacturing Processes and Systems
No full textProducts and material mixtures found in E-waste are highly inhomogeneous and in
continuous evolutions. In spite of this variability, state-of-the-art mechanical recycling
systems are extremely rigid, both in their design and parameter settings. This is mainly
due to the lack of knowledge-based engineering models and tools to support the design
and operation of separation processes able to capture, with an acceptable level of
confidence, all the major phenomena affecting the quality of the output, including
particle-particle interactions and impacts. In this paper, multi-body granular flow
simulation is proposed as a modeling and analysis tool able to capture the physics of
mechanical separation processes and to support process parameter design, operation
and control in industrial settings. The simulation of granular flows in waste material is
complicated by the non-smooth and discontinuous nature of the contact phenomena
between the particles, and between the particles and parts of the processing
equipment. The approach adopted in this paper, based on the recent theory of
Differential Variational Inequalities (DVI), is an alternative to the classical Discrete
Element Method (DEM), and it is suitable to handle up to millions of contacts between
particles, without decreasing integration time steps. The proposed models are validated
by experimental analysis carried out at the “De-manufacturing Pilot Plant” at ITIA-CNR.
Results show that this modeling framework can be used in practical settings to predict
the separation performance as a function of the process parameters
A computer-aided methodology for the optimization of electrostatic separation processes in recycling
Full text linkThe rapid growth of technological products has led to an increasing volume of waste electrical and electronic equipments (WEEE), which could represent a valuable source of critical raw materials. However, current mechanical separation processes for recycling are typically poorly operated, making it impossible to modify the process parameters as a function of the materials under treatment, thus resulting in untapped separation potentials. Corona electrostatic separation (CES) is one of the most popular processes for separating fine metal and nonmetal particles derived from WEEE. In order to optimize the process operating conditions (i.e., variables) for a given multi-material mixture under treatment, several technological and economical criteria should be jointly considered. This translates into a complex optimization problem that can be hardly solved by a purely experimental approach. As a result, practitioners tend to assign process parameters by few experiments based on a small material sample and to keep these parameters fixed during the process life-cycle. The use of computer experiments for parameter optimization is a mostly unexplored area in this field. In this work, a computer-aided approach is proposed to the problem of optimizing the operational parameters in CES processes. Three metamodels, developed starting from a multi-body simulation model of the process physics, are presented and compared by means of a numerical and simulation study. Our approach proves to be an effective framework to optimize the CES process performance. Furthermore, by comparing the predicted response surfaces of the metamodels, additional insight into the process behavior over the operating region is obtained
Parallel Simulation of Multidisperse Granular Flows using GPUs
No full textIn this paper, we present an application of GPU-based parallel computation for the simulation of multidisperse granular flows. We also show an application for the case of the Corona Electrostatic Separation (CES) process used in the waste management industry, where a strong electric field is used to separate plastic from metal particles in dense multidisperse granular flow of oddly-shaped fragments. The two major bottlenecks of the simulation are the collision detection and the solution of a complementarity problem at each time step; this limits the number of particles that can be simulated in reasonable time frames on the CPU, so we ported our simulation software to a parallel computing architecture. A custom collision detection has been used, where both broad-phase and narrow-phase collision stages have been designed in order to exploit parallel computation; such an algorithm is able to deal with particles of different shape and size, as needed in multidisperse granular flow. Also, a custom solver has been developed for solving the complementarity problem on parallel hardware. Such a solver requires multiple kernels and complex computational primitives because the complementarity problem does not fit in the perfectly-parallel computational paradigm, moreover, special care must be used to exploit data coalescence as much as possible. Finally, external force fields have been introduced, to simulate and reproduce the physics of electrostatic forces in the CES separation process
A simulation model of Corona Electrostatic Separation (CES) for the recycling of Printed Circuit Boards (PCBs)
No full text
A Multi-Body Simulation Model for a Corona Electrostatic Separator Machine
No full textCorona electrostatic separation (CES) is a process that separates conductive from non-conductive particles in recycling streams. Its range of application, specifically dedicated to the treatment of small particles (typically below 2 mm), makes it suitable for the mechanical separation of complex shredded material matrices, e.g. printed circuit boards or other waste electrical and electronic equipment. Therefore, a numerical model of this type would be useful for further optimization of machine parameters as a function of the input stream. In the literature, several attempts have been made to simulate particle trajectories in roll-type electrostatic separators. Although existing models are accurate in the simulation of the trajectories of single metal particles, they are not suitable to simulate the trajectories of a mixture of metal and plastic particles. In addition, they neglect particle-particle interactions and collisions. However, in real corona electrostatic separation systems, the quality of the separation is affected by the occurrence of impacts between particles, which increases the variability in the particle throws. Therefore, this limitation mines the applicability of existing models in an industrial settings. A more realistic model of CES is therefore needed to better capture the real behavior of the system and to provide a more accurate performance analysis of CES processes. This paper proposes a multi-body, multi-particle simulation model for the prediction of the metal and non-metal particles trajectories under the effect of particle-particle interactions and collisions using the differential variational inequalities (DVI) approach
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