Practical trainings, student assistants and theses

Calculation of multi-phase flow using the GENTOP model with FLUENT (Id 346)

Student practical training / Master theses / Diploma theses

Foto: Fig. 1: Boiling pipe flow (left: disperse gas volume fraction, right: continuous gas volume fraction) from Setoodeh et al., Applied Thermal Engineering 204 (2022) 117962 ©Copyright: Dr. Thomas HöhneAs a member of the Helmholtz Association of German Research Centers, the HZDR employs about 1,400 people. The Center's focus is on interdisciplinary research in the areas energy, health and matter. The Institute of Fluid Dynamics is conducting basic and applied research in the fields of thermo-fluid dynamics and magnetohydrodynamics in order to improve the sustainability, the energy efficiency and the safety of industrial processes.

Multiphase flows are important part of many industrial applications, whereas modelling of them is a challenging and complex task. For flow situations with higher void fractions, HZDR developed a new generalized concept for the CFD-simulations including flow regime transitions. The GENTOP (Generalized Two-Phase Flow) approach is able to simulate co-existing large-scaled (continuous) and small-scaled (polydispersed) structures (Fig. 1). Previous results were performed with the CFD code CFX and compared against DEBORA validation data.

The goal of the thesis would be to apply and improving the existing state of the simulations in the Fluent GENTOP framework.

We offer an interesting task dealing with complex physical phenomena, work in an international team using state-of-the-art calculation and programming methods.

We are looking for a motivated student (f/m/d) (master thesis) able to perform CFD simulations, understand and program code to generalize/parametrize CFD simulations, work with experimental data sets, document and present the work in an appropriate manner. Useful but not required is a knowledge of the following software tools: CFD codes CFX and Fluent, Python, GIT.

The task is supervised by Framatome and HZDR.

FRAMATOME is a designer and supplier of nuclear steam supply system and nuclear equipment, services and fuel for high levels of safety and performance. Framatome is a major international player in the nuclear energy market recognized for its innovative solutions and value-added technologies for designing, building, maintaining, and advancing the global nuclear fleet. The company designs, manufactures, and installs components, fuel and instrumentation and control systems for nuclear power plants and offers a full range of reactor services. With 14,000 employees worldwide, every day Framatome's expertise helps its customers improve the safety and performance of their nuclear plants and achieve their economic and societal goals.

Department: Computational Fluid Dynamics

Contact: Dr. Höhne, Thomas, Dr. Lucas, Dirk

Requirements

  • Studies in Engineering, Computer Science or comparable
  • Interest in numerical work
  • Good communication skills in both written and spoken English
  • Useful but not required is a knowledge of the following software tools: CFD codes CFX and Fluent, Python, GIT.

Conditions

  • A vibrant research community in an open, diverse, and international work environment.
  • Scientific excellence and extensive professional networking opportunities.
  • Compensation as student researcher (working hours to be determined).
  • Working place will be Dresden and/or Erlangen Germany.

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


Construction and test of a reference measurement system for an industrial wire-mesh sensor for multiphase flow measurements (Id 313)

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

Foto: reference measurements for multiphase measurement systems ©Copyright: Dr. Philipp WiedemannWire-mesh sensors allow for measuring the phase distribution of gas-liquid flows with high spatial and temporal resolution. For industrial applications (e.g. in power plants or chemical plants) previous projects already focussed on the development of data processing algorithms that convert the huge data sets into user friendly information, i.e. average void fraction and flow pattern. Hence, plant operators can now benefit from advanced process monitoring and operate their processes more efficiently.
The current developments focus on an enhanced system that includes online reference measurements in order to compensate drifts, which may result from changes of fluid properties when dealing with dynamic operation modes of the process. For this purpose, an existing concept should be converted into a final design, constructed and finally tested within the frame of an internship.

Department: Experimental Thermal Fluid Dynamics

Contact: Dr. Wiedemann, Philipp

Requirements

  • interest in practical work
  • manual skills
  • creativity
  • studies in process/energy/mechanical/electrical engineering
  • 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

Druckversion