References of "Peters, Bernhard 50002840"
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See detailA PRELIMINARY STUDY ON THE STABILITY OF PARTICLE LADEN JETS THROUGH A FULLY COUPLED CFD-DEM SOLVER
Peters, Bernhard UL; Pozzetti, Gabriele UL

Poster (2016, May 22)

Jets are widely used in engineering applications. In material machinery, hydro-transportation systems as well as in chemical industry it is common to deal with a dispersed solid phase interacting with the ... [more ▼]

Jets are widely used in engineering applications. In material machinery, hydro-transportation systems as well as in chemical industry it is common to deal with a dispersed solid phase interacting with the jet, and therefore creating a so-called slurry-jet or particle-laden jet. The stability of a jet is a key issue for many of these processes, still the underlying physics of this turbulent multiphase flow is highly complicated. Conventional CFD approaches have been proven satisfying for the study of the stability of two-phase jets. When a solid dispersed phase is present in the system, the stability problem gets more complicated and dependent on the solid phase dynamic. A possible solution for the problem is to extend the CFD solver capability through a correct coupling with a DEM solver. In this work a preliminary investigation on the potentialities of this kind of approach is presented and compared with a pure CFD approach. In particular the effect of the presence of differently sized particles in the jet is outlined and the influence of particle properties and concentration is investigated. Finally some considerations about the computational cost of different methods are proposed. The fluid phases are solved through an Eulerian finite volume (FV) multiphase solver based on the OpenFoam® libraries, and coupled with the XDEM code in order to treat the dispersed phase in a Lagrangian way. [less ▲]

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See detailA Combined Experimental and Numerical Approach to a Discrete Description of Indirect Reduction of Iron Oxide
Peters, Bernhard UL; Hoffmann, F.; Senk, D. et al

in LA METALLURGIA ITALIANA (2016), (3), 49-54

Blast furnaces are complex counter-current reactors designed to reduce chemically iron oxides and melt them to liquid iron. The complex processes in blast furnace iron making involve various aspects of ... [more ▼]

Blast furnaces are complex counter-current reactors designed to reduce chemically iron oxides and melt them to liquid iron. The complex processes in blast furnace iron making involve various aspects of thermodynamics, fluid dynamics, chemistry and physics. Physical, thermal and chemical phenomena occurring within the process are highly coupled in time and space. In order to generate a more detailed understanding of the indirect reduction of iron ore, the innovative approach of the Extended Discrete Element Method (XDEM) is applied. It describes the ore particle as discrete entities for which the thermodynamic state e.g. temperature and reduction degree through a reaction mechanism is described individually for each particle. The flow within the void space between the particles is represented by classical computational fluid dynamics that solves for the flow and temperature distribution including the composition of the gas phase. Ore particles and gas phase are tightly coupled by heat and mass transfer, that allows particles to heat up and to be provided with the reducing agent i.e. carbon monoxide. Reduction of iron oxide is predicted by a set of equilibrium reactions that represent the phase diagram of iron oxides at different oxidation levels. The reaction mechanism was validated by experimental data for a single ore particle for different temperatures. A comparison between measurements and predictions yielded good agreement so that reduction of iron oxide to iron was represented by a single mechanism including all reduction steps. The validated reaction mechanism was then applied to each particle of a packed bed that was exposed to define gas flow with its temperature and composition. The predicted results were also compared to experimental data and very good agreement was achieved. Due to the resolution of iron reduction on a particle level, detailed results of the entire reactor were obtained unveiling the underlying physics of the entire process. Results showed the reduction state of each particle during the entire period and additionally revealed the inhibiting influence of a non-uniform flow distribution. It provided regions of the packed bed with insufficient amounts of the reducing agent and thus, allowed identifying drawbacks for design and operation. [less ▲]

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See detailModeling of the biomass combustion on a forward acting grate using XDEM
Mahmoudi, Amir Houshang UL; Besseron, Xavier UL; Hoffmann, F. et al

in Chemical Engineering Science (2016), 142

The grate firing system is one of the most common ways for the combustion of biomass because it is able to burn a broad range of fuels with only little or even no requirement for fuel preparation. In ... [more ▼]

The grate firing system is one of the most common ways for the combustion of biomass because it is able to burn a broad range of fuels with only little or even no requirement for fuel preparation. In order to improve the fuel combustion efficiency, it is important to understand the details of the thermochemical process in such furnaces. However, the process is very complex due to many involved physical and chemical phenomena such as drying, pyrolysis, char combustion, gas phase reaction, two phase flow and many more. The main objective of this work is to study precisely the involved processes in biomass combustion on a forward acting grate and provide a detailed insight into the local and global conversion phenomena. For this purpose, XDEM as an Euler-Lagrange model is used, in which the fluid phase is a continuous phase and each particle is tracked with a Lagrangian approach. The model has been compared with experimental data. Very good agreements between simulation and measurement have been achieved, proving the ability of the model to predict the biomass combustion under study on the grate. © 2015 Elsevier Ltd. [less ▲]

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See detailHPC or the Cloud: a cost study over an XDEM Simulation
Emeras, Joseph; Besseron, Xavier UL; Varrette, Sébastien UL et al

in Proc. of the 7th International Supercomputing Conference in Mexico (ISUM 2016) (2016)

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See detailNumerical study of the influence of particle size and packing on pyrolysis products using XDEM
Mahmoudi, Amir Houshang UL; Hoffmann, F.; Peters, Bernhard UL et al

in International Communications in Heat & Mass Transfer (2016), 71

Conversion of biomass as a renewable source of energy is one of the most challenging topics in industry and academy. Numerical models may help designers to understand better the details of the involved ... [more ▼]

Conversion of biomass as a renewable source of energy is one of the most challenging topics in industry and academy. Numerical models may help designers to understand better the details of the involved processes within the reactor, to improve process control and to increase the efficiency of the boilers. In this work, XDEM as an Euler-Lagrange model is used to predict the heat-up, drying and pyrolysis of biomass in a packed bed of spherical biomass particles. The fluid flow through the void space of a packed bed (which is formed by solid particles) is modeled as three-dimensional flow through a porous media using a continuous approach. The solid phase forming the packed bed is represented by individual, discrete particles which are described by a Lagrangian approach. On the particle level, distributions of temperature and species within a single particle are accounted for by a system of one-dimensional and transient conservation equations. The model is compared to four sets of experimental data from independent research groups. Good agreements with all experimental data are achieved, proving reliability of the used numerical methodology. The proposed model is used to investigate the impact of particle size in combination with particle packing on the char production. For this purpose, three setups of packed beds differing in particle size and packing mode are studied under the same process conditions. The predicted results show that arranging the packed bed in layers of small and large particles may increase the final average char yield for the entire bed by 46 %. © 2015 Elsevier B.V. [less ▲]

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See detailXDEM for Tuning Lumped Models of Thermochemical Processes Involving Materials in the Powder State
Copertaro, Edoardo UL; Chiariotti, Paolo; Estupinan Donoso, Alvaro Antonio UL et al

in Engineering Journal (2016), 20(5), 187-201

Processes involving materials in gaseous and powder states cannot be modelled without coupling interactions between the two states. XDEM (Extended Discrete Element Method) is a valid tool for tackling ... [more ▼]

Processes involving materials in gaseous and powder states cannot be modelled without coupling interactions between the two states. XDEM (Extended Discrete Element Method) is a valid tool for tackling this issue, since it allows a coupled CFD- DEM simulation to be run. Such strength, however, mainly finds in long computational times its main drawback. This aspect is indeed critical in several applications, since a long computational time is in contrast with the increasing demand for predictive tools that can provide fast and accurate results in order to be used in new monitoring and control strategies. This paper focuses on the use of the XDEM framework as a tool for fine tuning a lumped representation of the non-isothermal decarbonation of a CaCO3 sample in powder state. The tuning of the lumped model is performed exploiting the multi-objective optimization capability of genetic algorithms. Results demonstrate that such approach makes it possible to estimate fast and accurate models to be used, for instance, in the fields of virtual sensing and predictive control. [less ▲]

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See detailBerechnung des Transportes von Treibgut bei Hochwasser
Peters, Bernhard UL; Pozzetti, Gabriele UL; Liao, Yu-Chung UL

in 39. DRESDNER WASSERBAUKOLLOQUIUM (2016)

Hochwasser hervorgerufen durch natürliche Ursachen wie Schneeschmelze oder durch bauliche Maßnahmen wie Flussbegradigung verursacht häufig eine Flutkatastrophe mit verheerenden Überschwemmungen. Zu den ... [more ▼]

Hochwasser hervorgerufen durch natürliche Ursachen wie Schneeschmelze oder durch bauliche Maßnahmen wie Flussbegradigung verursacht häufig eine Flutkatastrophe mit verheerenden Überschwemmungen. Zu den schon katastrophalen Folgen von Hochwasser addieren sich häufig noch die Schäden von gefährliche Treibgut, das mit den Fluten mitgerissen wird und unter Umständen über weite Strecken transportiert wird. Mitgerissenes Treibgut kann zur Verklausung von Brücken führen oder auch Bauwerke zerstören. Um die Folgen eines Hochwassers einschließlich Transport von Treibgut abschätzen zu können, sind numerische Werkzeuge eine adäquate Ergänzung zu experimentellen Methoden, die oft mit einem sehr hohen Aufwand verbunden sind. Deshalb wird im vorliegenden Beitrag eine neue und innovative numerischer Ansatz vorgestellt, der den Transport von Treibgut bei Hochwasser aber auch bei Normalwasser beschreibt. Dazu werden die beiden numerischen Methoden beruhend auf einem diskreten und kontinuierlichem Ansatz gekoppelt. Letzterer beinhaltet die Euler Methoden, mit denen die Strömung des Wassers im Rahmen von bewährten Rechenmethoden der Computational Fluid Dynamik (CFD) bestimmt wird. Treibgut wird diskret betrachtet, in dem es mit der Diskreten Element Methode (DEM) beschreiben wird. Damit kann sowohl jedes einzelne Element des Treibgutes berücksichtigt werden als auch seine Eigenschaften wie Größe, Form und Gewicht. Innerhalb dieses Ansatzes können die Kontaktkräfte zwischen den einzelnen Elementen des Treibgutes berechnet werden, mit denen sich Geschwindigkeit, Position und Orientierung des Treibgutes bestimmen lassen. Zusätzlich wird über eine Kopplung zur fluiden Phase der Einfluss sowohl der Wassergeschwindigkeit als des Auftriebs mit berücksichtigt. [less ▲]

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See detailA discrete-continuous approach to describe CaCO3 decarbonation in non-steady thermal conditions
Estupinan Donoso, Alvaro Antonio UL; Peters, Bernhard UL; Copertaro, Edoardo et al

in Powder Technology (2015), 275

In cement production, direct measurements of thermal and chemical variables are often unfeasible as a consequence of aggressive environments, moving parts and physical inaccessibility, and therefore ... [more ▼]

In cement production, direct measurements of thermal and chemical variables are often unfeasible as a consequence of aggressive environments, moving parts and physical inaccessibility, and therefore prediction models are essential tools in these types of industrial applications. This article addresses the problem of the numerical prediction of the CaCO3 calcination process, which is the first and the most energy expensive process in clinker production. This study was conducted using the Extended Discrete Element Method (XDEM), a framework which allows a Eulerian approach for the gas phase to be combined with a Lagrange one for the powder phase. A detailed validation of the numerical model was performed by comparison to non-isothermal TG curves for mass loss during the CaCO3 decarbonation process. The complex three-dimensional predictions for solid and gas phases are believed to represent a first step towards a new insight into the cement production process. Thus, the high accuracy and detailed description of the problem addressed, serve as a basis to assess the uncertainty of more simplified models such as those used in soft sensors. [less ▲]

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See detailXDEM Used for Predicting Tungsten-Oxide Reduction
Estupinan Donoso, Alvaro Antonio UL; Peters, Bernhard UL

Scientific Conference (2015, April 27)

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See detailPerformance Evaluation of the XDEM framework on the OpenStack Cloud Computing Middleware
Besseron, Xavier UL; Plugaru, Valentin UL; Mahmoudi, Amir Houshang UL et al

in Proceedings of the Fourth International Conference on Parallel, Distributed, Grid and Cloud Computing for Engineering (2015, February)

As Cloud Computing services become ever more prominent, it appears necessary to assess the efficiency of these solutions. This paper presents a performance evaluation of the OpenStack Cloud Computing ... [more ▼]

As Cloud Computing services become ever more prominent, it appears necessary to assess the efficiency of these solutions. This paper presents a performance evaluation of the OpenStack Cloud Computing middleware using our XDEM application simulating the pyrolysis of biomass as a benchmark. We propose a systematic study based on a fully automated benchmarking framework to evaluate 3 different configurations: Native (i.e. no virtualization), OpenStack with KVM and XEN hypervisors. Our approach features the following advantages: real user application, the fair comparison using the same hardware, the large scale distributed execution, while fully automated and reproducible. Experiments has been run on two different clusters, using up to 432 cores. Results show a moderate overhead for sequential execution and a significant penalty for distributed execution under the Cloud middleware. The overhead on multiple nodes is between 10% and 30% for OpenStack/KVM and 30% and 60% for OpenStack/XEN. [less ▲]

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See detailExperimental and numerical investigation into iron ore reduction in packed beds
Peters, Bernhard UL; Hoffmann, F.; Senk, D. et al

in Chemical Engineering Science (2015)

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See detailPredicting Tungsten Oxide Reduction with the Extended Discrete Element Method
Estupinan Donoso, Alvaro Antonio UL; Peters, Bernhard UL

in Advances in Powder Metallurgy Particulate Materials (2015), (Proceedings of the 2015 International Conference on Powder Metallurgy Particulate Materials), 0235--0248

During technical reduction of tungsten trioxide powder in hydrogen atmospheres, the local temperature and the ratio of water vapor to hydrogen partial pressures govern the conversion rate. Water vapor ... [more ▼]

During technical reduction of tungsten trioxide powder in hydrogen atmospheres, the local temperature and the ratio of water vapor to hydrogen partial pressures govern the conversion rate. Water vapor removal rate not only affects the conversion progress, but also drives the final metallic tungsten powder size distribution. The amount of water vapor inside the bed depends on the hydrogen flow, the height of powder beds and the size characteristics of the initial oxide. The chemically aggressive environment and high temperatures make it difficult to do the measurements inside the reactors for studying or control the process. On the other hand, multi-physics computational techniques help to understand the evolution of the complex phenomena involved in the process. This contribution presents the eXtended Discrete Element Method as a novel approach to investigate the complex thermochemical conversion of tungsten oxides into tungsten metal. The recently emerged technique is based on a coupled discrete and continuous numerical simulation framework. In the study, an advanced and consolidated two-phase Computational Fluid Dynamics (CFD) tool for porous media represents gaseous phase penetration and transport. The discrete feedstock description includes one-dimensional and transient distributions of temperature and species for each powder particle. This allows gaining a new and valuable insight into the process, which may lead into finer tungsten powder production, and consequently more resistant tungsten carbide products. Transient and spatial results for powder composition, gas species as well as a mass loss comparison with experimental data for non-isothermal hydrogen reduction of tungsten trioxide are demonstrated and discussed. [less ▲]

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See detailA Discrete Approach to Describe the Elastic-plastic Behaviour of Snow
Peters, Bernhard UL; Michael, M.; Nicot, F.

in Fourth Conference on Particle-Based Methods (PARTICLES 2015) (2015)

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See detailThe Extended Discrete Element Method (XDEM) as a Flexible and Advanced Tool in Multi-physics Applications
Peters, Bernhard UL

in 26th International Symposium on Transport Phenomena (2015)

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See detailA Combined Experimental and Numerical Approach to a Discrete Description of Indirect Reduction of Iron Oxide
Peters, Bernhard UL; Hoffmann, F.; Senk, D. et al

in SteelSim 2015, MODELLING and SIMULATION of METALLURGICAL PROCESSES in STEELMAKING (2015)

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See detailA discrete/continuous numerical approach to multi-physics
Peters, Bernhard UL; Besseron, Xavier UL; Estupinan Donoso, Alvaro Antonio UL et al

in IFAC-PapersOnLine (2015), 28(1), 645-650

A variety of technical applications are not only the physics of a single domain, but include several physical phenomena, and therefore are referred to as multi-physics. As long as the phenomena being ... [more ▼]

A variety of technical applications are not only the physics of a single domain, but include several physical phenomena, and therefore are referred to as multi-physics. As long as the phenomena being taken into account is either continuous or discrete i.e. Euler or Lagrangian a homogeneous solution concept can be employed. However, numerous challenges in engineering include continuous and discrete phase simultaneously, and therefore cannot be solved only by continuous or discrete approaches. Problems include both a continuous and a discrete phase are important in applications of the pharmaceutical Industry e.g. drug production, agriculture and food processing industry, mining, construction and Agricultural machinery, metal production, power generation and systems biology. The Extended Discrete Element Method (XDEM) is a novel technique, which provides a significant advance for the coupled discrete and continuous numerical simulation concepts. It expands the dynamics of particles as described by the classical discrete element method (DEM) by a thermodynamic state or stress/strain coupled as fluid flow or structures for each particle in a continuum phase. XDEM additionally estimates properties such as the interior temperature and/or species distribution. These predictive capabilities are extended to fluid flow through an interaction by heat, mass and momentum transfer important for process engineering. © 2015, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved. [less ▲]

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See detailAssessing Heat Transfer Through Walls Of Packed Bed Reactors By An Innovative Particle-Resolved Approach
Peters, Bernhard UL; Singhal, A.; Besseron, Xavier UL et al

in 18th IFRF Member's Conference (2015)

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See detailA discrete-continuous approach to describe CaCO3 decarbonation in non-steady thermal conditions
Copertaro, Edoardo UL; Chiariotti, Paolo; Estupinan Donoso, Alvaro Antonio et al

in Powder Technology (2015), 275

In cement production, direct measurements of thermal and chemical variables are often unfeasible as a consequence of aggressive environments, moving parts and physical inaccessibility, and therefore ... [more ▼]

In cement production, direct measurements of thermal and chemical variables are often unfeasible as a consequence of aggressive environments, moving parts and physical inaccessibility, and therefore prediction models are essential tools in these types of industrial applications. This article addresses the problem of the numerical prediction of the CaCO3 calcination process, which is the first and the most energy expensive process in clinker production. This study was conducted using the Extended Discrete Element Method (XDEM), a framework which allows a Eulerian approach for the gas phase to be combined with a Lagrange one for the powder phase. A detailed validation of the numerical model was performed by comparison to non-isothermal TG curves for mass loss during the CaCO3 decarbonation process. The complex three-dimensional predictions for solid and gas phases are believed to represent a first step towards a new insight into the cement production process. Thus, the high accuracy and detailed description of the problem addressed, serve as a basis to assess the uncertainty of more simplified models such as those used in soft sensors. [less ▲]

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See detailMultiskalenmodellierung für technische Anwendungen
Peters, Bernhard UL

in ECEMP 2015, European Centre for Emerging Materials and Processes (2015)

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See detailROS homeostasis in a dynamic model: How to save PD neuron?
Kolodkin, Alexey UL; Ignatenko, Andrew UL; Sangar, Vineet et al

Poster (2014, December)

Detailed reference viewed: 128 (14 UL)