Practical trainings, student assistants and theses

Experimental investigation of two phase (Liquid-Gas) flow regime within a porous frit bubble generator, and its influence on bubble size and gas fraction distribution in the downcomer. (Id 367)

Bachelor theses / Master theses / Diploma theses / Compulsory internship

Understanding of bubble generation mechanism and evaluation of bubble size is critical for any process (e.g. reaction in a bubble column, mineral flotation process etc.). The size of the bubbles and its flow regime in the column/reactor determines the hydrodynamics which influences the reaction kinetics or recovery of the minerals in a flotation cell. There are different methods to generate microbubbles, one of them using a porous frit (commonly used in the industries due to simple design and its robustness). Two-phase flow regimes (slug, plug, annular, bubbly etc.) are well investigated in vertical and horizontal tube/pipe configuration. This study is focused on a porous frit bubble generator with an aim to understand the regimes within the frit and its influence on the rest of the system.

Research question:

Different flow regimes are observed in the frit at varying process conditions and the regimes influences the bubble size and the gas phase distribution in the downcomer.

Primary objectives of this study are:

1. Identifying the flow regime of the bubbles within the frit at varying process condition using the shadowgraphy technique,
2. Quantification of bubble size using a process microscope as it moves down the downcomer (vertical tube downstream of the frit) and,
3. Determine the gas fraction distribution using a wire mesh sensor.

For details please refer:

https://tu-dresden.de/ing/maschinenwesen/ifvu/tpg/ressourcen/dateien/shk/2022-07-20_RFC_Vaishakh.pdf?lang=en

Department: Transport processes at interfaces

Contact: Tholan, Vaishakh, Dr. Heitkam, Sascha

Requirements

1. Field of study: chemical engineering, process engineering, fluid mechanics, physics or similar field of study,
2. High motivation for experimental research,
3. Understanding of fluid mechanics,
4. Working independently,
5. Matlab/Python and Image post processing will be an added advantage.

Conditions

1.Working/Collaboration in an international team,
2. Will gain experience in sophisticated measurement techniques used in experimental fluid dynamics,
3. Duration: at least 6 months,
4. Location: TU Dresden.

Online application

Please apply online: english / german

Druckversion


Characterization of radiotracers for tumor imaging (Id 360)

Bachelor theses / Master theses / Compulsory internship

Within the framework of various research projects of the Department of Radiopharmaceutical and Chemical Biology, novel radiotracers, labeled for example with the imaging radionuclides fluorine-18, iodine-123 or copper-64, will be evaluated preclinically in vitro and in vivo. In addition, novel cell models (2D, 3D) will be established to be biochemically and biologically characterized. Depending on the prerequisite (field of study) and main interest, a variety of chemical, radiochemical, biochemical, molecular and cell biological as well as radiopharmacological methods and techniques can be learned and applied. While working scientifically on your topic, you will also acquire transferable key skills such as scientific writing, presentation skills, critical thinking and project planning

Department: Radiopharmaceutical and Chemical Biology

Contact: Prof. Dr. Pietzsch, Jens

Requirements

  • Studies/degree in chemistry, biochemistry, biology or a related field
  • Strong interest in scientific work in an interdisciplinary team
  • Independent working style and excellent communication skills
  • High level of commitment and motivation
  • Willingness to work with open radioactive materials

Conditions

  • Start usually at the beginning of the semester or by arrangement
  • Internship duration at least 16 weeks

Online application

Please apply online: english / german

Druckversion


Motion tracking of autonomous sensor particles in industrial vessels (Id 335)

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 fluid properties such as temperature and electrical conductivity inside the vessel must be known. This can be achieved by the autonomous flow-following sensor particles developed by the HZDR. Equipped with a pressure sensor, an accelerometer, two gyroscopes and a magnetometer, the sensor particle can track the movement inside the vessels and derive the flow field from that. Additionally, the sensor particle gets position information by an ultra-wide-band based localization module (like GPS) as soon as it is on the fluid surface. The motion of the sensor particle is currently tracked with an error-state Kalman filter and yields a reliable tracking of the velocity and position, respectively. However, the tracking time is limited by the propagation of uncertainties of the inertial sensors through the filter. The objective of this master thesis is to extend this tracking time by the use of more advanced tracking algorithms like particle filter or other types of Kalman filters. This includes the following tasks:

  • Literature review of advanced filters for motion tracking
  • Theoretical comparison and implementing the most promising algorithm in Python
  • Verification and performance analysis based on experimental data

Department: Experimental Thermal Fluid Dynamics

Contact: Buntkiel, Lukas, Dr. Reinecke, Sebastian

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

Druckversion


Experimental investigation of influence of interfacial viscoelasticity on the dripping to jetting transition (Id 333)

School practical training / Student practical training / Bachelor theses / Master theses / Compulsory internship

Foto: Capillary with jetting liquid-liquid interface ©Copyright: Milad EftekhariLiquid jets are unstable and eventually form droplets to minimize the surface energy with the surrounding fluid. The transition from dripping to jetting and dynamics of the droplet pinch-off have been studied extensively for various systems, from pure Newtonian fluids to complex non-Newtonian liquids. The jetting process has received significant attention as it is a critical step in various three-dimensional (3D) printing techniques such as dropwise additive manufacturing and the direct ink writing method. In most of the applications surface active materials such as surfactants, nanoparticles, and polymers exist in the systems. The presence of surface-active materials reduces the liquid-fluid surface energies and in some cases generates a viscoelastic layer at the interface.
In this research, we aim to study the influence of interfacial viscoelasticity on the dripping to jetting transition. The study is conducted by the injection of an aqueous phase (nanoparticle dispersions) into an oil phase that contains surfactants over a wide range of flow rates. We tune the magnitude of interfacial viscoelasticity by changing the concentration of surfactants and nanoparticles.
Research question:
Does the dripping to jetting transition (critical flow rate) linearly increase by increasing the interfacial viscoelasticity?

Experiments:

1. Measurements of interfacial tension and surface elasticity for a range of particle and surfactant concentration using Profile analysis tensiometry, and Langmuir trough.
2. Dripping to jetting experiments for the selected systems using high-speed cameras and in-house setups.

Department: Transport processes at interfaces

Contact: Eftekhari, Milad, Dr. Schwarzenberger, Karin

Requirements

  • Field of study: chemical engineering, process engineering, fluid mechanics, or similar focus in chemistry or physics
  • Experience with laboratory work and imaging measurement techniques is beneficial

Conditions

  • Working in an international team
  • Duration: at least 6 months
  • Location: Dresden-Rossendorf

Online application

Please apply online: english / german

Druckversion