PhD - Thermal-Fluid Optimization of Heat Sinks Including Manufacturability Constraints KU Leuven Applied Mechanics and Energy Conversion Section Belgium


The Thermal and Fluids Engineering research group headed by Prof. M. Baelmans focuses on modeling, numerical simulation, and optimization of thermal, fluid and kinetic transport phenomena. Embedded in KU Leuven’s Mechanical Engineering Department, Applied Mechanics and Energy Conversion Section, applications range from thermal management in electronic components, over heat transfer and storage devices to thermal networks and nuclear fusion reactors. Starting from dedicated component and system models, existing designs are critically reviewed and implicit design assumptions are challenged. This leads to innovative concepts and designs for electronic devices, coolers, heat exchangers and integrated energy systems. Due to a wide range of applications, a unique combination of expertise in CFD and advanced optimization techniques is available within the research group. Its close collaboration with renowned research institutions in the region such as IMEC, EnergyVille, SCK-CEN and Forschungszentrum Juelich, as well as the expertise available in our comprehensive university, add on to the unique and inspiring research environment we create.



Whereas topology optimization has been successfully applied in structural mechanics for more than two decades, its application to systems with fluid flow has not been investigated until 2002. More recently, topology optimization has also proven its merit for optimizing the lay-out of systems with steady and unsteady (laminar) incompressible flow. In contrast, topology optimization for the combination of flow and heat transfer is a new research domain, which is, e.g., attractive for developing compact heat sinks for electronics cooling. Topology optimization of heat sinks then allows designing novel and more efficient cooling configurations that are fitted to a specific application. At Thermal and Fluids Engineering group at KU Leuven, topology optimization methods based on two-dimensional physical models have been developed for compact electronics cooling. Also most of the work found in literature is concentrated on optimizing two-dimensional lay-outs. Yet, given the increasing flexibility in manufacturing techniques such as 3D printing, 3D designs for heat sinks with extended surfaces come in reach. Efficiently dealing with the computational cost of 3D problems will be the main challenge of the PhD candidate, as well as guaranteeing robustness of the design and its manufacturability.


Within this PhD research several optimization methodologies for manufacturable heat sink topologies for single phasefluids (liquid or gas) are therefore examined. Both state-of-the-art manufacturing processes as well as technologies presently used for other applications will be characterized through their specifications with respect to tolerances and achievable aspect ratios, strength, etc. In order to come up with realistic topologies, the fluid channels need to have minimal cross-sections to prevent the channels from blocking due to fouling. On the other hand, too tiny structures might bend or even break. For the latter the optimizer needs to be extended with mechanical integrity constraints.


Since computational efficiency is crucial for the successful application of topology optimization to 3D heat sink design, one-shot methods will be examined to speed up the optimization. These methods, known from aerodynamic shape optimization, simultaneously solve the simulation and optimization problem and are typically able to reduce the computation cost of the entire optimization to about 5-10 times the cost of a single simulation. In order to proceed towards full 3D heat sink topology optimization for steady state flow conditions, the PhD candidate will need to efficiently implement the method, while seeking further acceleration with other fundamental computational concepts such as multigrid methods. Furthermore, practical problems such as guaranteeing connectivity of the structures in 3D designs will need to be solved. The final goal is to obtain 3D automated designs of compact heat sinks for electronics cooling.



We are looking for a highly motivated, enthusiastic and communicative researcher with a Master of Science degree in Engineering, or a related field, from a reputable institute. Candidates with a background in e.g. numerical optimization and computer science are also encouraged to apply. Strong analytic skills are required, as evidenced by excellent study results.


The candidate should have a strong interest in flow and heat transfer modelling for energy systems, and a sound background in numerical methods. Knowledge of numerical optimization methods is also a plus, as well as experience with coding languages such as python, C++, and MATLAB. Applicants should also have good English communication skills.



KU Leuven is among the top European universities. The Thermal and Fluids Engineering group under the lead of Prof. Martine Baelmans has a long and well-proven track record in numerical research on combined flow and heat transfer problems.Through i.a. collaborations within EnergyVille, a research collaboration on sustainable energy between KU Leuven, VITO, imec and Uhasselt, the group keeps a close link to the application side.


We offer:

  • A KU Leuven doctoral scholarship (fully funded) for four years (net monthly salary of about ~ €2,000), and a PhD degree in Engineering if successful.
  • Multiple benefits (health insurance, access to university infrastructure and sports facilities, etc.)
  • Being part of a dynamic research environment with fellow young researchers and experts from both the numerical simulation and optimization side, as well as from the application side.
  • The opportunity to be active in an international research environment, engage in research collaborations and participate at international conferences.
  • A targeted start date is to be agreed upon.



Applicants should express their interest by sending an email to prof. Martine Baelmans and her team via the dedicated email address The email should *strictly* contain the following information in the text body, in bullets:

  • Name
  • Master degree (Master specification, University + Country, Year obtained, Promotor)
  • Master thesis title
  • A one paragraph (up to half an A4 page) statement explaining the motivation for applying for this vacancy at KU Leuven. Please also indicate here which project you apply for


Please also attach an academic CV to your email. Do not directly apply in the online system as referred to below. This will be only necessary for selected candidates in a second stage. Note that if you do not receive a response to your email within three weeks, this means you have not been selected for the second stage. Decision: as soon as a suitable candidate applies (so do not wait till the closing date to apply). For more information please contact prof Martine Baelmans and her team via


You can apply for this job no later than January 15, 2019 via the online application tool

KU Leuven seeks to foster an environment where all talents can flourish, regardless of gender, age, cultural background, nationality or impairments. If you have any questions relating to accessibility or support, please contact us at

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