Ejector Geometry Design Analysis Procedure For Fuel Cell Drives
master's thesis, project report

The Chair of Alternative Vehicle Drives (ALF) conducts research in the fields of electromobility, hydrogen power, and PEM fuel cells. As is the case with traditional power drives, fuel cell electric drives esentially depend on peripheral components for a normal, sustained functioning, so these components are also part of our research area.

The operation of fuel cell systems for powertrains necessitates a continuous anode fuel recirculation, which is carried out by a pumping device carefully designed or selected for the task. For low to medium power units subject to narrow operating load ranges, ejectors (jet pumps) have found a niche use, mainly due to their simplicity, reliability, and low maintenance cost. The downside is that the fixed geometry of an ejector has to be designed very carefully to cover its required operating range.

The main objective of the student project is to develop a methodology and tools for the design, manufacturing and testing of hydrogen ejectors for fuel cell applications. Development of parameterized tools to design the ejector geometry for various operating windows is also desirable. Within the scope of this research work, the following subtasks are expected to be implemented:

• Literature and market research.

• Overview of ejector fluid mechanics theoretical background.

• Review of already existing jet pumps used in fuel cell drive technologies with regard to their performances.

• Definition of ejector parametric performance maps as requirement from fuel cell system operation dynamics.

• Model evaluation and comparison of different geometries.

• Application of FEM/CFD simulations (optional)

• Evaluation of the results and transfer into a scientific paper format.

The work is to be submitted as an individual work. The main points can be individually adapted to the work status or the necessary steps in consultation with the supervisor.