Practical trainings, student assistants and theses

Experimental investigation of the multiphase flow in a stirred tank with PIV and Shadowgraphy (Id 277)

School practical training

Foto: Motivation_StirredTank ©Copyright: Anna-Elisabeth Sommer, Flotation cell: https://www.matsamining.com/innovacion/planta-de-tratamiento/With the energy turnaround, the demand for rare earth elements (REE) for key technologies such as lithium for electromobility or neodymium for wind turbines is increasing. The effective processing and separation of these valuable minerals represent a challenge for the mineral industry. One possibility for separation is flotation. Flotation separates the solid particles based on their surface wettability. Hydrophobic valuable particles adhere to gas bubbles and rise as agglomerates. These form a froth which can be skimmed off. The selective separation is influenced by the hydrodynamics in the flotation cell. The optimization of existing flotation cells or the development of new ones has a great potential for more effective separation of REE. Of particular interest are numerical models of flotation cells. In these models, process parameters can be changed much more versatile and easier than in experimental investigations. For this purpose, however, it is necessary to understand the processes taking place in flotation based on experimental studies and also to generate data for the validation of numerical models. In this work, a comprehensive experimental study of multiphase flow in the stirred tank with Particle Image Velocimetry (PIV) and shadowgraphy, concerning flow conditions and material parameters, is to be carried out. The results will help to improve the understanding of multiphase flow within the stirred tank and provide validation data for numerical models.

FOCUS OF WORK
• Investigation of the influence of solid particles and bubbles on the multiphase flow in the stirred tank with PIV and shadowgraphy
• Development of suitable algorithms for data evaluation with MatLab or Python
• Cooperation with CFD department for comparison of experimental and numerical results

Department: Transport processes at interfaces

Contact: Sommer, Anna-Elisabeth

Requirements

• Studies in process/energy/mechanical engineering
• Interest in practical work
• Experience in programming with MatLab or Python is beneficial
• Good written and oral communication skills in English and German

Conditions

• Start: immediately
• Duration: ca. 6 months

Online application

Please apply online: english / german

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Experimentelle Untersuchung des Stofftransportes in Blasenströmungen (Id 268)

Master theses / Diploma theses / Compulsory internship

Foto: Visulalsierung des Produktes der Reaktion von Fe(EDTA) und NO ©Copyright: Ragna KippingBlasensäulen sind ein beliebter Reaktortyp für die Durchführung von gas-flüssig Reaktionen in der chemischen Industrie. Sie zeichnen sich durch hohe Stofftransportraten und eine gute Durchmischung aus. Die Auslegung dieser Apparate basiert jedoch meist auf groben Abschätzungen, da die in Blasensäulen ablaufenden Prozesse sehr komplex sind. Dieses Projekt befasst sich mit der Untersuchung des Stofftransportes an Einzelblasen und Blasengruppen. Die zu untersuchende Reaktion ist eine Modellreaktion und zeichnet sich durch die Bildung eines farbigen Reaktionsproduktes aus und kann spektroskopisch erfasst werden.

Die Aufgabenstellung umfasst:
- Literaturrecherche
- Durchführung der Stofftransportmessungen an einem bestehenden Versuchsaufbau im Chemielabor
- Auswertung der gewonnenen Messdaten vorzugsweise mit Matlab
- Dokumentation und Vergleich mit Literaturdaten

Department: Experimental Thermal Fluid Dynamics

Contact: Kipping, Ragna

Requirements

- Studium des Chemie-Ingenieurwesen, Verfahrenstechnik, o.ä.
- Freude am experimentellen Arbeiten
- Laborerfahrung wünschenswert
- Erfahrungen im Umgang mit Matlab von Vorteil

Conditions

Dauer: 4-6 Monate

Links:

Online application

Please apply online: english / german

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Nonlinear characterization of horizontal gas-liquid flows (Id 266)

Student practical training / Bachelor theses / Master theses / Diploma theses / Compulsory internship / Research Assistant

Foto: Nonlinear characterization of horizontal gas-liquid flows ©Copyright: Dr. Philipp WiedemannHorizontal gas-liquid flows occur in a variety of processes in energy and process engineering. According to the type of fluids, operating conditions and geometrical aspects different flow patterns are observed. These can be identified successfully by means of online monitoring systems when using appropriate measurement techniques and data processing algorithms.
Within the frame of an internship further investigations will focus on the predictability of the future development of the flow patterns on the basis of currently measured data. For that purpose, methods for characterizing nonlinear systems will be applied to available data that was recorded with the aid of an imaging technique.

Department: Experimental Thermal Fluid Dynamics

Contact: Dr. Wiedemann, Philipp

Requirements

- studies in mathematics/physics/engineering
- interest in applying sophisticated mathematical methods to engineering problems
- experience in signal processing and nonlinear systems is beneficial
- good written and oral communication skills in English and German

Conditions

- start: immediately
- working in a multi-disciplinary team
- remuneration according to HZDR internal regulations

Links:

Online application

Please apply online: english / german

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Energetische Bewertung der CO2-Abtrennung von Syngasturbinen mittels intensiverter Trennapparate (Id 263)

Master theses / Diploma theses

Um die von der europäischen Union anvisierten Klimaziele zu erreichen muss eine deutliche Reduktion der CO2-Emissionen erfolgen. Hierbei ist eine Abtrennung von CO2 bei nicht substituierbaren Quellen wie der Zement und Stahlindustrie notwendig. Weiterhin werden dezentrale Blockheizkraftwerke einen wesentlichen Beitrag zur Lastflexibilität leisten und somit die Versorgungsstabilität (Backbone) für den Fall gewährleisten, dass erneuerbare Energien temporär nicht verfügbar sind. Da mittelfristig ein Betrieb dieser Blockheizkraftwerke mit Erdgas und punktuelle CO2-Quellen nicht zu vermeiden sind, ist ein geeignetes Konzept zur effizienten CO2-Abtrennung erforderlich. Ein Ansatzpunkt ist die Kopplung von Gasturbine und HiGEE-Trennapparaten über einen gemeinsamen Rotor. HiGEE-Apparate bestehen aus rotierenden Packungen, in denen Waschmittel und Rauchgas unter Ausnutzung der Zentrifugalkraft kontaktiert werden.

Im Rahmen der Arbeit ist eine Recherche zu CO2-Punktquellen in Deutschland und Europa durchzuführen und die CO2-Emissionen sind quantitativ und qualitativ einzuordnen. Ein Konzept zur CO2-Abscheidung ist energetisch zu bewerten. Exemplarisch sollen Betriebsdaten (Leistung, Wirkungsgrad, Abgaszusammensetzung und -temperatur) eines Blockheizkraftwerkes angenommen werden. Daten zur CO2-Abtrennung mittels HiGEE-Apparate sind aus der Literatur zu extrahieren.

Folgende Teilarbeiten sind durchzuführen:

- Recherche zu CO2-Punktquellen in Deutschland und Europa
- Recherche/Analyse der Überschussstromproduktion in Deutschland anhand einer Beispielregion
- Ausstellen der Wärme- und Stoffbilanzen und möglicher energetischer Verschaltungen (Wärmerückgewinnung)
- Abschätzungen erforderlicher HiGEE-Apparategrößen
- Bestimmung des Turbinenwirkungsgrades unter Berücksichtigung des Desportionsprozesses

Department: Experimental Thermal Fluid Dynamics

Contact: Fogel, Stefan, Unger, Sebastian

Requirements

Student (m/w/d) im Bereich Energietechnik, Chemie- oder Elektroingenieurwesen, Verfahrenstechnik oder ähnlicher fachlicher Ausrichtung.
Kenntnisse in Aspen Plus, ChemCAD oder ähnlichen Programmen sowie gute Sprachkenntnisse in Englisch.

Conditions

Mindestdauer: 6 Monate; ab sofort durchführbar.

Online application

Please apply online: english / german

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Development of a GUI for a Python simulation tool (Id 261)

Student practical training / Bachelor theses / Master theses / Diploma theses / Compulsory internship / Volunteer internship

Foto: Lithium liquid metal electrode ©Copyright: ©Steffen Landgraf, Michael NimtzFor a software project (simulation tool in Python 3), a graphical user interface (based on Tkinter or Qt) shall to be developed. The goal is to configure, start and evaluate simulations via the GUI. Consequently, all interfaces must be developed or modified, the operator panel must be designed and all needed testing and error-handling routines must be implemented.

Note: This is an offer suitable for a bachelor, master or diploma thesis or studentic internships.
Do not apply if you already finished your studies!

Department: Magnetohydrodynamics

Contact: Dr. Nimtz, Michael

Requirements

Study informatics or similar.
Good knowledge of a programming language, preferably python as well as experience with the implementation of GUIs.
Basic knowledge of engineering principles is beneficial.
Good command of English.

Conditions

Start: from November 2019
Duration: 4-6 months
Paid according to HZDR-internal tariff

Links:

Online application

Please apply online: english / german

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Gas phase simulation of pressure wave in a gas-injection pipe (Id 259)

Student practical training / Bachelor theses / Master theses / Diploma theses

Foto: Bubble Formation ©Copyright: Ehsan Mohseni, Ehsan MohseniIn two-phase flows, the interface at which the phases are in contact to one another is of high importance. One way to manipulate the dynamic of this interface is to modulate the pressure field within the gas phase. Accordingly, it is intended to study the influence of pressure modulation in a gas pipe with multiple openings. In this content, the system characteristics should be defined and the effect of individual parameters, which influence the temporal change of the pressure field at the openings are going to be studied. These parameters include frequency and amplitude of excitations, pressure fluctuation, geometry of the pipe and the openings, gas flow rate, etc. To peruse this idea, it is intended to simulate the gas pressure field in the pipe and under the opening using COMSOL Multiphysics.

Task Spectrum:
• Establishment of a profound scientific knowledge in the field of acoustics and wave propagation
• Literature review on interacting two phase flows and pressure waves
• Establishing the simulation strategy
• Model the geometry, flow domain, establishing the initial and boundary condition
• Performing the simulation with various geometries and post processing the result
• Generate scientific documentation

Department: Experimental Thermal Fluid Dynamics

Contact: Mohseni, Ehsan, Dr. Reinecke, Sebastian

Requirements

• Studies in mechanical, chemical, process engineering, and similar engineering courses
• Experience in simulation with COMSOL Multiphysics
• Optionally but not necessarily experience with acoustic module of COMSOL Multiphysics
• Independence, self-responsible working methods

Conditions

Duration: 6 Months

Online application

Please apply online: english / german

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Modelling of bubble formation on submillimeter submerged orifice (Id 258)

Student practical training / Bachelor theses / Master theses / Diploma theses

Foto: Bubble Formation ©Copyright: Ehsan Mohseni, Ehsan MohseniBubbles are an inevitable part of almost all chemical and process engineering processes as long as heat and mass transfer or particle separation are concerned. Formation of bubbles from a submerged orifice is a typical fluid dynamic phenomenon, which incorporates the influence of different characteristics of both gas and liquid phases. Although posing as a simple problem in the first sight, the formation process varies dramatically by changing influential parameters such as diameter and geometry of orifice, volume of gas reservoir under the orifice, surface tension, density and viscosity of both continuous and dispersed phases, etc. Among these parameters, the effect of the volume of the gas reservoir under the orifice is highly influential. Within an ongoing investigation, we are experimentally studying the effect of this parameter on the dynamics of bubbles generated at orifices smaller than 1 mm. A sub task of this investigation associates the findings of the experimental studies into a mechanistic model, which is designed to estimate the final bubble size.

Task Spectrum:
• Establishment of a profound scientific knowledge into the phenomena of bubble formation and detachment
• Concept development and establishing solution strategy for the bubble volume
• Implementing the solutions into MATLAB
• Compare and adopting the model based on the experimental results
• Generate scientific documentation

Department: Experimental Thermal Fluid Dynamics

Contact: Mohseni, Ehsan, Dr. Reinecke, Sebastian

Requirements

• Studies in mechanical, chemical, process engineering, and similar engineering courses
• Experience in data analysis and programming with MATLAB
• Independence, self-responsible working methods

Conditions

Duration: 6 Months

Online application

Please apply online: english / german

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Design and operation of liquid metal batteries as large-scale storage option (Id 256)

Student practical training / Bachelor theses / Master theses / Diploma theses / Compulsory internship / Volunteer internship

Foto: Study of a liquid metal battery module ©Copyright: Dr. Michael Nimtz, ©Michael NimtzIn contrast to conventional batteries, Liquid Metal Batteries feature all liquid anodes (alkaline or alkaline earth metal), cathodes (transition metal or metal) and electrolytes (molten salts) at a temperature between 400 °C and 600 °C. For the operation of liquid metal batteries as large-scale storage option (frequency control and other applications), the design of the storage system and operation strategies (including a battery management system) need to be implemented and tested using exemplary load curves.
Starting point is an existing model of a battery system in Python.

Note: This is an offer suitable for a bachelor, master or diploma thesis or studentic internships.
Do not apply if you already finished your studies!

Department: Magnetohydrodynamics

Contact: Dr. Nimtz, Michael

Requirements

Study of mechanical engineering, physics, mathematics or similar
Basic knowledge of engineering principles.
Good knowledge of a programming language, preferably python.

Conditions

Start: October 2019
Duration: 4-6 months
Paid according to HZDR-internal tariff

Links:

Online application

Please apply online: english / german

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Investigation of the flow behavior of fluidized particles by means of coupled CFD-DEM simulations (Id 253)

Master theses / Diploma theses / Compulsory internship / Research Assistant

Foto: CFD-DEM fluidized bed ©Copyright: Dr. Philipp WiedemannFluidized beds are widely applied in process plants of pharmaceutical, food and chemical industries. Due to the complex flow structure optimization of such devices and process control is usually supported by simulations. However, since it is not feasible to resolve all spatial and temporal scales within a single simulation environment, large-scale simulations require reliable sub-models in order to account for small-scale phenomena correctly.
Therefore, the macroscopic flow properties of fluidized particles will be investigated by means of CFD-DEM simulations within the frame of an internship. Research will focus on the influence of different particle size distributions. The results shall lead to enhanced insight into the complex gas-solids-interaction of fluidized beds and will be incorporated into future developments.

Department: Experimental Thermal Fluid Dynamics

Contact: Dr. Wiedemann, Philipp

Requirements

• studies in chemical/mechanical/process/computational engineering
• interest in multiphase flow phenomena
• good written and oral communication skills in English and German
• knowledge in computational fluid dynamics

Conditions

• start: immediately
• scope of work: up to 6 months (according to study regulations)

Online application

Please apply online: english / german

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Smart actuation system for flow following µAUV particles for industrial process environments (Id 175)

Master theses / Diploma theses / Compulsory internship

Foto: flow following sensor particle ©Copyright: Dr. Sebastian ReineckeSmart flow following sensor particles are used for acquisition of spatially distributed process parameters in industrial processes, such as biogas digesters, waste water treatment basins or bioreactors. The aim of the work is the development of an actuator concept for sensor µAUV-particles for the automatic adjustment of buoyancy (buoyancy) and for buoyancy maneuvers under the condition of small size, minimum energy consumption and high reliability. For this, alternative physical and chemical mechanisms should be considered based on the existing electromechanical solution. There are suitable variants to implement and test. Furthermore, the development of sensor intelligence for the actuators in the sensor particles is an essential part of the task. The developed concepts have to be validated experimentally.

We cordially invite you to an on-site conversation to introduce the topic and to agree on further details. Do not hesitate to contact us, because the way is worth it for you.

What can you expect:

In our department, we offer you an attractive work environment to expand your personal and professional skills. The insight into the diverse R&D projects of the department in the areas of sensor and measuring technology as well as energy and process engineering (among others) and the excellent technical equipment of the laboratories offer optimal conditions for this. The possibility of close contact with competent experienced colleagues plays a central role. As part of student work, we have pursued the approach of structured supervision and associated constructive feedback. This includes regular meetings with your supervisor and intermediate presentations in the form of informal "workshop reports" in the extended audience of interested individuals of the department in order to optimally support you in the successful completion of your project. Furthermore, we are open to support outstanding candidates in their continuing academic qualification, such as in doctoral scholarships or in current or upcoming R&D projects.

Subject-related task spectrum:

• Establishment of the scientific and technical principles of mechanical, physical and chemical principles of action for embedded, actuating components
• Concept development for actuators for taring of sensor particles
• Development of sensor intelligence for situation-dependent, automatic buoyancy, for buoyancy maneuvers and for recovery
• Selection, purchase/ composition and comparison of solution variants
• Minimization of size and energy consumption
• Increased reliability when used in particle-loaded biological substrates
• Development of firmware taking into account existing function routines based on an embedded system with 32-bit data structure (e.g. STM32)
• Conception and realization of suitable test scenarios
• Characterization and comparison of implemented variants with regard to accuracy of taring and reliability in long-term use

Department: Experimental Thermal Fluid Dynamics

Contact: Dr. Reinecke, Sebastian, Buntkiel, Lukas

Requirements

• Studies in electrical engineering, mechatronics, mechanical engineering and similar engineering courses
• Experience in design and (micro) actuator systems
• Experience in programming microcontrollers for embedded systems (e.g. STM32)
• Experience in control electronics for microdrives and board design for embedded systems
• Fundamentals of (micro) actuator systems, movement of rigid bodies, measurement uncertainties, digital signal processing
• Data analysis optionally in Matlab, Octave or C / C ++
• Independent, self-responsible working method

Links:

Online application

Please apply online: english / german

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Bestimmung von Geschwindigkeitsfeldern aus tomographischen Bilddaten mittels Kreuzkorrelation (Id 164)

Bachelor theses / Master theses / Diploma theses

Foto: ROFEX CAD ©Copyright: Dr. Frank BarthelAm Institut für Fluiddynamik am Helmholtz-Zentrum Dresden-Rossendorf sind zahlreiche Messverfahren für die Untersuchung von Mehrphasenströmungen entwickelt worden. Eines davon ist die ultraschnelle Elektronenstrahl-Röntgen-Computertomographie, welche mit Aufnahmeraten von bis zu 8000 Bildern pro Sekunde eine dedizierte Aufklärung von Strömungsstrukturen erlaubt. Aufgrund der quasi simultanen Aufnahme von Bilddaten aus zwei Messebenen ergibt sich zudem die Möglichkeit, axiale Geschwindigkeiten zu bestimmen, wofür üblicherweise Kreuzkorrelationsverfahren verwendet werden. Im Rahmen dieser Arbeit sollen die Möglichkeiten dieser Methodik in Hinblick auf die Bestimmung von Geschwindigkeitsfeldern in verschiedenen Strömungsszenarienn analysiert werden.

Folgende Teilaufgaben sind zu lösen:
• Studie zu verschiedenen Varianten der Kreuzkorrelation
• Simulation verschiedener Szenarien und Bewertung der Genauigkeit
• Übertragung der Ergebnisse auf reale Messungen

Department: Experimental Thermal Fluid Dynamics

Contact: Dr. Bieberle, Martina

Requirements

• Studium der Informatik, Mathematik oder einer Ingenieurwissenschaft
• Interesse an Messverfahren und Datenanalyse
• Selbständiges Arbeiten

Conditions

Bearbeitungszeit 4 bis 6 Monate

Links:

Online application

Please apply online: english / german

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Untersuchung des Einflusses von Regularisierungsmethoden auf Bildrekonstruktionsalgorithmen (Id 57)

Student practical training / Bachelor theses / Master theses / Diploma theses

Bei der tomographische Bildrekonstruktion muss ein diskretes inverses Problem gelöst werden, wofür algebraische Methoden wie zum Beispiel ART und CG-Verfahren verwendet werden können. Dabei spielt die Regularisierung, die den Einfluss von Diskretisierungsfehler und Messdatenrauschen auf die Lösung beschränkt, eine entscheidende Rolle. Deren Einfluss auf die Bildrekonstruktion von Röntgen- und Gamma-CT-Messdaten soll untersucht werden. Dazu sind folgende Teilaufgaben zu lösen:
• Implementierung verschiedener Regularisierungsmethoden
• Anwendung der Programme auf Messdaten
• Parameterstudien um die Regularisierungsmethoden für die Messdatensätze zu optimieren.

Department: Experimental Thermal Fluid Dynamics

Contact: Dr. Wagner, Michael, Dr. Bieberle, Martina

Requirements

• Programmierkenntnisse in MATLAB
• Grundkenntnisse zur numerischen Behandlung linearer Gleichungssysteme

Links:

Online application

Please apply online: english / german

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