PhD Position Flow of Multiphase Systems Through Constrictions: From 2D to 3D

Emulsions are encountered in many applications. Their behaviour is usually studied in relatively flat microchannels. How does this change when we go to 3D?

Job description

Bulk flow behaviour of emulsions is governed by the dynamics at the droplet scale, i.e. microscopic properties alter the macroscopic ones. To obtain insights into multiphase flow at the droplet scale, microfluidics is a powerful and well-established tool. While these measurements provide valuable information, the results are dominated by the confined nature of the geometries that are used in the experiments: the channels have a large width-to-height ratio, making them essentially ‘2D’. This results in behaviour that may be significantly different than what would happen in real-life bulk systems. For example, droplet confinement extends the upper range of critical capillary numbers where coalescence is induced and enhances droplet deformation and subsequent break-up of single droplets. Performing measurements in 3D would overcome this problem, and bring us closer to the conditions observed in applications. However, this requires a considerable push in the state-of-the-art in multiphase measurements in microfluidic systems, as the full volume cannot be easily accessed using a standard microscope.

In this project, you will develop a 3D measurement technique and apply it to study emulsion behaviour (such as coalescence and phase inversion). The first half of the project will focus on the development of tomographic imaging techniques to capture oil/water distributions in a 3D geometry. In the second half, we will use these techniques to study the flow and stability of an emulsion through a constriction, gradually moving from 2D to 3D geometries using microfluidic devices fabricated in-house.

You will be part of the Multiphase Systems group within the Process & Energy Department at TU Delft. The group studies fundamental and applied aspects of multiphase flows, combining advanced experiments and state-of-the-art numerical simulations. Research focuses on dense dispersions, turbulence interacting with free surfaces, and transitions in particle-laden flows, with applications ranging from slurries and food emulsions to 3D printing and transport of floating structures.

Within the group, you will work in a collaborative and international environment, which has access to unique experimental facilities such as MRI, X-ray, and ultrasound imaging, alongside high-performance computing resources. The position entails conducting experimental research, publishing in peer-reviewed journals, presenting at conferences, and mentoring BSc and MSc students. The group values open interaction, knowledge sharing, and teamwork, fostering both individual growth and collective scientific excellence.

Job requirements

We are looking for a self-motivated and creative candidate with:

• An MSc degree in Mechanical Engineering, Chemical Engineering, Applied Physics, or a related field.
• A strong foundation in (multiphase) fluid dynamics.
• Proven experience with experimental work and a drive to explore and improve state-of-the-art techniques.
• Image/data processing skills in Python or Matlab.
• Proficiency in written and spoken English.

Doing a PhD at TU Delft requires English proficiency at a certain level to ensure that the candidate is able to communicate and interact well, participate in English-taught Doctoral Education courses, and write scientific articles and a final thesis.

Conditions of employment

Doctoral candidates will be offered a 4-year period of employment in principle, but in the form of 2 employment contracts: an initial 1.5-year contract with an official go/no go progress assessment within 15 months, followed by an additional contract for the remaining 2.5 years assuming performance requirements are met.

As a PhD candidate you will be enrolled in the TU Delft Graduate School. The TU Delft Graduate School provides an inspiring research environment with an excellent team of supervisors, academic staff and a mentor. The Doctoral Education Programme is aimed at developing your transferable, discipline-related and research skills.

The TU Delft offers a customisable compensation package, discounts on health insurance, and a monthly work costs contribution. Flexible work schedules can be arranged.