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 current 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. For more details please check the Graduate Schools Admission Requirements.

TU Delft (Delft University of Technology)
Delft University of Technology is built on strong foundations. As creators of the world-famous Dutch waterworks and pioneers in biotech, TU Delft is a top international university combining science, engineering and design. It delivers world class results in education, research and innovation to address challenges in the areas of energy, climate, mobility, health and digital society. For generations, our engineers have proven to be entrepreneurial problem-solvers, both in business and in a social context.

At TU Delft we embrace diversity as one of our core values and we actively engage to be a university where you feel at home and can flourish. We value different perspectives and qualities. We believe this makes our work more innovative, the TU Delft community more vibrant and the world more just. Together, we imagine, invent and create solutions using technology to have a positive impact on a global scale. That is why we invite you to apply. Your application will receive fair consideration.

Challenge. Change. Impact!

Faculty Mechanical Engineering
From chip to ship. From machine to human being. From idea to solution. Driven by a deep-rooted desire to understand our environment and discover its underlying mechanisms, research and education at the ME faculty focusses on fundamental understanding, design, production including application and product improvement, materials, processes and (mechanical) systems.

ME is a dynamic and innovative faculty with high-tech lab facilities and international reach. It’s a large faculty but also versatile, so we can often make unique connections by combining different disciplines. This is reflected in ME’s outstanding, state-of-the-art education, which trains students to become responsible and socially engaged engineers and scientists. We translate our knowledge and insights into solutions to societal issues, contributing to a sustainable society and to the development of prosperity and well-being. That is what unites us in pioneering research, inspiring education and (inter)national cooperation.

Click here to go to the website of the Faculty of Mechanical Engineering. Do you want to experience working at our faculty? These videos will introduce you to some of our researchers and their work.

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 everything goes well and performance requirements are met.

Salary and benefits are in accordance with the Collective Labour Agreement for Dutch Universities, increasing from €3059 - €3881 gross per month, from the first year to the fourth year based on a fulltime contract (38 hours), plus 8% holiday allowance and an end-of-year bonus of 8.3%.

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.

Will you need to relocate to the Netherlands for this job? TU Delft is committed to make your move as smooth as possible! The HR unit, Coming to Delft Service, offers information on their website to help you prepare your relocation. In addition, Coming to Delft Service organises events to help you settle in the Netherlands, and expand your (social) network in Delft. A Dual Career Programme is available, to support your accompanying partner with their job search in the Netherlands.

Additional information
For more information about this specific position or the application procedure, please contact Prof. C. Poelma (C.Poelma@tudelft.nl).

Application procedure
Are you interested in this vacancy? Please apply no later than 5 April 2026 via the application button and upload the following documents:

• Curriculum vitae
• Motivation letter highlighting your relevant research skills and motivation for doing this PhD project
• Diplomas and transcripts of your BSc. and MSc. studies, including a certified list of grades

You can address your application to Prof. C. Poelma.

Please note:

• You can apply online. We will not process applications sent by email and/or post.
• As part of knowledge security, TU Delft conducts a risk assessment during the recruitment of personnel. We do this, among other things, to prevent the unwanted transfer of sensitive knowledge and technology. The assessment is based on information provided by the candidates themselves, such as their motivation letter and CV, and takes place at the final stages of the selection process. When the outcome of the assessment is negative, the candidate will be informed. The processing of personal data in the context of the risk assessment is carried out on the legal basis of the GDPR: performing a public task in the public interest. You can find more information about this assessment on our website about knowledge security.
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