Practical trainings, student assistants and theses

Internship - Wastewater Treatment Plant Flexibilization (Id 291)

Compulsory internship

Background:
Uncertainty in influent quantity and quality related to increasingly extreme weather events is an expected outcome of climate change that will severely affect the design and operation of wastewater treatment systems. On top of this, the transition to renewable, weather dependant energy sources required to fight climate change will cause energy availability and prices to fluctuate much more than in the past. New approaches to wastewater treatment plant control are needed to ensure reliable performance and minimal operational costs in the face of such uncertain boundary conditions.

Tasks:
- Collection and analysis of online-available data sources (weather and energy markets)
- Running of wastewater treatment plant operation simulations for different scenarios
- Result assessment with the aim of increasing system reliability and cost-efficiency

Department: Experimental Thermal Fluid Dynamics

Contact: Parra Ramirez, Mario Alejandro, Dr. Reinecke, Sebastian

Requirements

- Currently enrolled in M.Sc. programme on environmental engineering, chemical engineering, biochemical engineering, or a similar field with relevant knowledge on wastewater treatment and management
- Experience with simulation tools for wastewater treatment plants (ASM/BSM models, SIMBA) is desirable
- Enthusiasm for working independently in international and interdisciplinary teams on scientific projects
- Experience on the preparation of scientific reports and effective communication of research results
- Proficiency in English is required, knowledge of German is desirable

Conditions

- A vibrant research community in an open, diverse, and international work environment
- Scientific excellence and extensive professional networking opportunities
- Salary during the internship period

Online application

Please apply online: english / german

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Simulation of gas-solid-liquid flows in stirred tanks (Id 290)

Bachelor theses / Master theses / Diploma theses / Student Assistant / Compulsory internship

Multiphase flows with particles and bubbles play an important role in many process engineering applications. Use of CFD („Computational fluid dynamics“) methods offers the possibility to identify energy- and resource-efficient solutions for scale-up and intensification of such processes, which are costly and time-consuming to investigate by conventional semi-empirical methods. Such simulations on the scale of technical equipment are feasible within the Euler-Euler framework, where phenomena on the scale of individual bubbles or particles are modeled. The development of such closure models is a focus of the research in the CFD department of the Institute of Fluid Dynamics at HZDR.
The topic of the present work is the combination of already established models for bubbly or particulate two-phase flows to a model for three-phase flows in which both bubbles and particles are present. To validate this model, simulations are run using ANSYS CFX and compared to experimental data from the literature. The degree of agreement between both is discussed and hypotheses for eventual deviations are suggested. Since our group has many years of experience with this procedure, good chances for quick accomplishment are provided.

Subtaks to work on are the following:
• systematic literature research on experimental databases
• running simulations
• evaluating and documenting the results
• eventually implementation of improved models

Department: Computational Fluid Dynamics

Contact: Dr. Rzehak, Roland

Requirements

• knowledge on fluid dynamics
• experience with ANSYS CFX is advantageous, but can also be acquired if committment is there
• Englisch language skills in writing and speech
• excitement about scientific work

Conditions

• duartion: 4-6 months
• begin: immediately
• compensation

Online application

Please apply online: english / german

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Image processing for surface flow tracking (Id 288)

Compulsory internship

Foto: Fermenter ©Copyright: Dr. Sebastian ReineckeBackground:
Mixing and homogeneity in large vessels, such as in biogas digesters and wastewater oxidation basins, determines stability, efficiency and productivity of the processes. However, achieving efficient mixing of the huge reactor volumes is a big challenge, since there is a lag of monitoring methods to characterize the flow patterns inside the closed vessels.

Objective:
The project focusses on the development of image processing algorithms for surface flow tracking. Sample images of typical flow behavior are captured by a conventional camera system continuously. These data sets shall be used to develop the tracking algorithms for surface flow, floating layer and homogeneity preferably with available software toolboxes, e.g. imagej, U-net, octave or others.

Tasks:
- Survey on flow imaging toolboxes
- Definition of target parameters for data extraction
- Screening of available sample data sets
- Implementation of imaging processing and data extraction routines
- Documentation and presentation of results

Department: Experimental Thermal Fluid Dynamics

Contact: Dr. Reinecke, Sebastian

Requirements

Studies in the area of computer science, informatics, electrical, mechanical engineering or similar
• Comprehensive knowledge of digital image analyses (optical flow, pattern recognition)
• Basics of machine learning based image processing (e.g. U-net)
• Independent and structured way of working

Online application

Please apply online: english / german

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6-month internship on the experimental investigation of granular mixing (Id 285)

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

Background:
Granular mixing is an important industrial process. In the pharmaceutical industry for instance, the powder that is pressed to make tablets is produced by mixing precise quantities of active substances and excipients in granular state. The mixing needs to be done in such a way that the final powder has a homogeneous composition. Tablets may also need to be coated in a pan coater. Granular mixing also plays a crucial role there, as it greatly affects the thickness of the coating. Granular mixing is also often coupled with heat exchanging and solid-gas or solid-solid reactions, as is the case of rotary kilns in the cement, ceramics and metallurgical industries. The quality of the mixing is then a crucial factor to the efficiency of the overall process.

Objectives:
The objective of the work is to experimentally study the mixing process of two different types of granular particles inside a rotating drum under various operating conditions. More specifically, the mixing process is to be captured with a high-speed camera. The videos are then to be post-processed in order to extract characteristics of the particle velocity fields and mixing efficiency. The mixing facility is already available.

Tasks:
• Literature survey
• Mixing experiments under various operating conditions
• Post-processing of the results with MATLAB

Department: Experimental Thermal Fluid Dynamics

Contact: Papapetrou, Theodoros Nestor

Requirements

• Student of natural sciences or engineering
• Willingness to conduct experimental work

Conditions

Duration: 6 months
Remuneration: available

Online application

Please apply online: english / german

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Contributions to motion tracking of autonomous flow-following sensor particles in industrial process environments (Id 279)

Bachelor theses / Master theses / Diploma theses / Compulsory internship

Foto: AutoSens_StirredReactor ©Copyright: fwdf (Mailgruppe)Data acquisition in large industrial vessels such as biogas fermenters or wastewater treatment plants is limited to local measurement points due to limited access to the vessel and the non-transparency of the fluid. To optimize these kinds of plants, the three-dimensional flow field and the spatial distribution of properties such as temperature and electrical conductivity inside the vessel need to be known. This can be achieved by the autonomous flow-following sensor particles developed by HZDR. Equipped with a pressure sensor, an accelerometer, two gyroscopes and a magnetometer, the sensor particle can track the movement inside the vessels and to infer the flow field from that. The analysis of the data is done after a successful recovery from the vessel. Therefore, algorithms of any complexity can be used to track the motion of the sensor particle.

For the extension and especially for the improvement of the motion tracking we offer the following tasks, from which we can agree on a topic for a thesis or an internship:
• Development of motion tracking algorithms
• Characterization and error correction of the sensors
• Intelligent sampling for the sensors
• Experimental investigation of the maximal acceleration on a stirrer
• Development of firmware to cover several data acquisition scenarios
• Development of an end-user program for the configuration and data analysis of the gathered data

Department: Experimental Thermal Fluid Dynamics

Contact: Buntkiel, Lukas

Requirements

Studies in the area of electrical, mechatronic, mechanical engineering or similar
• Basics of measurement uncertainty, digital signal processing
• Data analysis in Python
• Independent and structured way of working

Conditions

Start possible at any time
Duration according to the respective study regulations

Links:

Online application

Please apply online: english / german

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

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

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 efficiency of this process still remains far below the economically and ecologically desired targets for the 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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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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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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