Present Projects

DEM Simulation of the deposition and structure-formation of charged nanoparticles in electric fields

Title

DEM Simulation of the deposition and structure-formation of charged nanoparticles in electric fields

Funding

MWK, 12.2016-11.2019

Person in

Charge
M.Sc. Hector Fernando Rusinque Olaya

 

The discrete element method (DEM) is a versatile tool to model and compute the movement of large numbers of discrete particles including their interactions based on basic principles. This allows investigating the influence of electric fields on the transport and deposition of particles considering various forces such due to inertia, aerodynamics or electric fields without empirical simplifications. In the present PhD thesis, this method shall be employed to perform morphological studies of structures of charged nanoparticles under the influence of electric fields. The computational method is based on the OpenFOAM library. Based on that, the computational methods shall be further developed to consider the forces acting on charged particles in electric fields and the change of particle charge during deposition and collisions. The planned simulations are computationally very demanding and shall be realized using high performance and parallel computers such as the HLRN (Norddeutscher Verbund für Hoch- und Höchstleistungsrechnen). The work will be carried out in closed cooperation with project 4 (Elektrodynamisch kontrollierter Aufbau von 3D-Strukturen aus Funktions¬nano¬partikeln) and project 5 (Analytische Berechnung von 2D- und 3D-Strukturen maximaler Entropie und neuer Material-Modifikationen).

 

Kooperation: 

Professor Dr. Alfred Weber 
Institut für Mechanische Verfahrenstechnik

Prof. Dr. rer. nat. Heinz Sturm
Fachbereich Nanotribologie und Nanostrukturierung von Oberflächen (BAM Berlin)

 

Link: http://www.campus-fws.de/


Development of an ultrasound reactor for recovery process of scrap from steel and metal industry

Title

Development of an ultrasound reactor for recovery process of scrap from steel and metal industry

Funding

AiF, 09860/15, 2016 - 2018

Person in

Charge
M.Sc. Sergey Lesnik

 

The worldwide consumption and increasing shortage of raw materials require an efficient utilization of the resources. For instance, the strategic raw materials like titan, cobalt, wolfram and nickel, which are important for the carbide industry, can be economically recycled from scrap. During a hydrometallurgical recovery process, solvents dissolve the metals in a chemical reactor, which is also known as “chemical leeching”. To achieve an economic recovery process an efficient reactor technology is needed. The goal of the project is the deployment of ultrasound to accelerate the chemical leeching. The dissolution rate of scrap parts is increased through the cavitation caused by ultrasound. The research proposal includes numerical investigation on ultrasound field in the reactor and its geometrical optimization. The project is carried out in cooperation with VDEh-Betriebsforschungsinstitut from Düsseldorf, which is responsible for experiments.


Measurement and modeling of bubble populations in acoustic cavitation

Title

Measurement and modeling of bubble populations in acoustic cavitation

Funding

DFG normal procedure, BR 1864, 2014-2016

Person in

Charge
M.Sc. Sergey Lesnik

 

The project deals with the modeling of acoustical waves, which produce cavitation bubbles in a fluid, and their interaction among each other. Acoustic caviation is widely spread in process engineering (e.g. sonochemistry). The methods currently used in numerical simulations are not capable to reproduce the complex mechanisms satisfactorily. The goal of the project is to make it possible to give a better prediction of the propagation and the effect of acoustic cavitation using the combined approach of novel numerical techniques and modern measurement methods. The experimental part is conducted by the Third Institute of Physics at Georg-August-Universität Göttingen.

The animation shows the middle slice through a cuvette, which is equipped with two transducers at the bottom. The lower legend “Ap” describes the ultrasound pressure. Caviation bubbles are oversized for better visualization. The real diameter can be depicted from the left legend.


Improving diffusive mass transport in hierarchically structured Fischer-Tropsch catalysts

Title:

Improving diffusive mass transport in hierarchically structured Fischer-Tropsch catalysts

Funding:

DFG Schwerpunktprogramm 1570, 2011 - 2017

Person in charge:Dipl.-Ing. Eugenia Barthelmie

Das Porensystem eines Cobalt-basierten Katalysators für die Fischer-Tropsch-Synthese ist bei typischen Reaktionsbedingungen vollständig mit flüssigen Kohlenwasserstoffen gefüllt. Dies führt zu einer geringeren Katalysatorausnutzung und insbesondere zu reduzierter Selektivität und verringertem Umsatz in Hinblick auf langkettige Kohlenwasserstoffe durch Bildung von unerwünschtem Methan. Der Zusammenhang zwischen Porenmorphologie und der Katalysatoraktivität sowie Produktselektivität wird in Kooperation mit dem Institut für Chemische und Elektrochemische Verfahrenstechnik (ICVT) und dem Institut für Mechanische Verfahrenstechnik (MVT) der TU Clausthal in diesem Projekt untersucht. Dazu werden Transportvorgänge und chemische Reaktionen in flüssiger Phase innerhalb multimodaler synthetisch generierter sowie per Computertomographie aufgenommener realer Porensysteme am ITM numerisch quantifiziert. Als numerische Verfahren zur Bestimmung der Transport- und Reaktionskoeffizienten dienen die Lattice-Boltzmann und die Random-Walk-Particle-Tracking Methoden wegen ihrer hohen räumlichen Auflösung. Die ermittelten Parameter werden an die AG Turek des ICVT zur Prozesssimulation und Katalysatorcharakterisierung in einem Fischer-Tropsch-Reaktormodell übergeben; gemeinsam mit der AG Weber des MVT werden Optimierungsstrategien für Schichtaufbauten aus sog. Building Blocks erprobt. So zeigen theoretische und experimentelle Arbeiten vorangegangener Projektphasen, dass größere, insbesondere parallele, zylindrische Transportporen in der Katalysatorstruktur die Zugänglichkeit des Porensystems deutlich verbessern. Eine weitere Steigerung der Katalysatorausnutzung soll durch eine möglichst omniphobe Beschichtung der Porenoberflächen erreicht werden, sodass sie weitgehend frei von flüssigen Produkten bleiben. Derartigen Poren werden im Projekt mit unterschiedlichen Methoden hergestellt, theoretisch modelliert und experimentell erprobt.

Further info


Numerically intensive simulations on an integrated computing infrastructure

Title:

Numerically intensive simulations on an integrated computing infrastructure

Funding:

SWZ (56110660), 2016-2018

Person in charge

Alexander Bufe, M. Sc.

This project is a coorperation with the reasearch groups of Prof. Grabowski, University of Göttingen and Prof. Yahyapour, GWDG. Additional support in the development of numerical methods for the application will be received from the research group of Prof. Deiterding from Southampton University. The project part of the Institute of Applied Mechanics has the following goals: From an engineering point of view the aim of this project is to develop an understanding of material transport and transformation in porous materials. The background of the project is the increasing demand in various fields of engineering, for example, chemical engineering, to design porous materials and to use them for example as supports for catalysts with improved conversion rates and selectivity. Therefore it is necessary to be able to predict the morphology-transport relationships involving chemical reactions more accurately than previously possible.

For the mathematically point of view the main task is the development of suitable numerical methods. The starting point for this are works which are already performed by the cooperation partner in the field of computational fluid dynamics, in particular the lattice Boltzmann (LB) method, the adaptive mesh refinement and the parallel and high performance computing and cloud computing. Until now there are only some raw theoretical models for calculation of multiphase fluids in such structures which are based on the LB method. To use this method for calculation of technically relevant porous structures, further developments are needed to dissolve the processes running on very different length scales in numerical methods.

 

cooperation partners:

Prof. Dr. phil. nat. Jens Grabowski
Institut für Informatik, Georg-August-Universität Göttingen

Prof. Dr. rer. nat. Ramin Yahyapour
Institut für Informatik, Georg-August-Universität Göttingen
und Gesellschaft für wissenschaftliche Datenverarbeitung mbH Göttingen

Prof. Dr. rer. nat. Ralf Deiterding
University of Southampton, England

Further info


 

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