Power and Flow focuses on clean and efficient process technology, to cater for fast-growing energy demands. Our mission is to perform world-class scientific research on multiphase and reactive flows in the area of energy conversion and process technology. The research is concerned with the development of computational and experimental techniques for the study of multiphase reactors. This includes, for example, multiphase flow modeling of intensified contacting in bubble column reactors and multiphase processes in fluidized beds. Typical applications of this research include the automotive, chemical industries and additive manufacturing.

Project description

Additive manufacturing (AM) or 3D printing is a technique in which parts are produced by adding material. It allows for direct manufacturing of one of a kind, end-use parts with complex geometries directly from a digital building plan, in a cost and time efficient manner. In addition, AM has the ability to reduce the amount of waste, for example by reusing residual raw materials. One of the most advanced printing techniques for metals is powder bed-based printing, such as Laser Powder Bed Fusion (LPBF), where thin layers of micron-sized metal powder, with a thickness of 20-100 micron, are deposited in a build chamber and locally fused by a laser or an electron beam to create a solid part.

The entire metal 3D printing production chain, including the production of powder from scrap material, involves a number of processes that require different equipment. These processes include 1) the production of metal powder occurring in a molten metal atomizer, 2) after treatments such as sieving to narrow the particle size distribution, 3) transport and feeding the metal powder in the 3D printer, 4) deposition of the metal powder in a bed layer and 5) the actual 3D printing. The process can be made even more efficient if the 5 different steps are combined in a single device which uses waste molten metal or unused metal powder as input to produce a metal 3D printed solid part.  This requires the integration of state-of-the-art printing techniques with a technology able to generate and deposit metal powder.

The aim of this project is to design, build and test an atomization-deposition system. The project has three main objectives:

1. Generation of metal powder: The main design and processing characteristics of atomization of metallic melts by ultrasonic process are found and their effect on the efficiency of the process and properties of powders are investigated.
2. Deposition of metal powder: The best deposited layer of metal powder is obtained varying frequency, amplitude and molten metal flow rate of the ultrasonic atomizer. After that the time of deposition needs to be optimized depending on the amount of powder generated and the motion of the atomizer to a different position.
3. Integration of the system: all components are integrated in a 3D metal printer, taking into account all interactions between different stages of product realization.

Project team

The supervisors for this project are dr. Giulia Finotello and prof. Niels Deen from the section Power and Flow and dr. Joris Remmers from the section Mechanics of Materials. The research interests of Giulia Finotello include development of advanced experimental techniques and numerical tools to investigate spraying dynamics. Joris Remmers is an expert in the field of the analysis of mechanical properties of 3D printed products. The collaboration between the two sections allows to relate the properties of the spraying process with the mechanical structure and properties of the 3D printed parts.

Talented, enthusiastic candidates with excellent analytical and communication skills holding a master's degree in Mechanical Engineering, Materials Science or related field are encouraged to apply. The following skillsets are required:

• Proven hands-on experience in multiphase flows.
• Experience with spray characterization techniques such as phase Doppler interferometry (PDI)/PDA is beneficial.
• Experience with particle / flow simulation tools is beneficial.
• Strong experimental and design background.
• Affinity with (structural) design and integrated design concepts.
• Experience to work in a multi-disciplinary team of researchers.
• Excellent communication skills and written/verbal knowledge of the English language.

• A meaningful job in a dynamic and ambitious university with the possibility to present your work at international conferences.
• A full-time employment for four years, with an intermediate evaluation (go/no-go) after nine months.
• To develop your teaching skills, you will spend 10% of your employment on teaching tasks.
• To support you during your PhD and to prepare you for the rest of your career, you will make a Training and Supervision plan and you will have free access to a personal development program for PhD students (PROOF program).
• A gross monthly salary and benefits (such as a pension scheme, pregnancy and maternity leave, partially paid parental leave) in accordance with the Collective Labor Agreement for Dutch Universities.
• Additionally, an annual holiday allowance of 8% of the yearly salary, plus a year-end allowance of 8.3% of the annual salary.
• Should you come from abroad and comply with certain conditions, you can make use of the so-called '30% facility', which permits you not to pay tax on 30% of your salary.
• A broad package of fringe benefits, including an excellent technical infrastructure, moving expenses, and savings schemes.
• Family-friendly initiatives are in place, such as an international spouse program, and excellent on-campus children day care and sports facilities.