Project B8 (finished)
B8 - Jens Struckmeier, Stefan Heitmann: Real-time Design of Experiments for Fuel Cell operation
Principal investigator: Jens Struckmeier
Background and Motivation
Driving a fuel cell system in aircraft operation is a challenging task. Air feed fuel cells meet variable environmental pressure levels in regular aircraft operation. The variation of the system pressure results in changes of fuel cell performance. The project aims to measure the performance and efficiency of a polymer electrolyte membrane fuel cell system subject to ambient and low pressure conditions. The very first low test pressure test facility was assembled by the German Aerospace Center, Institute of Engineering Thermodynamics. The fuel cell system is subject to different operation parameters (pressure, cooling temperature, stochiometry and load requirement).
Aims and Objectives
It is virtually impossible to explore all the different combinations of operating parameters in an experimental set-up. Therefore, an experimental set-up based on the concept of Design of Experiments was computed before the measurements were started. This methodology allows to use much fewer but carefully chosen experimental runs. Stated differently, the 'design-space' is allowed to be as sparse as possible.
Mathematically, the concept may be based (other criteria are possible) on maximizing the differential Shannon estimates of the parameter estimates. Loosely speakings, by maximizing the determinant of the inverse of the variance matrix, it is attempted to maximize the 'available information'. Maximizing the determinant of a matrix requires the iterative solution of a non-linear optimization problem.
However, this work must be repeated regularly: it turned out during experimental runs that there are many non-admissible operation areas especially at low pressure operation. As a result, desired points in design-space cannot be reached since they might damage the fuel cell system. As this only shows up while the experiments are running the points in design-space must be redistributed in real-time.Student: a Master Thesis in this project has been completed in September 2016.
Werner, Claudia und Gores, Florian und Busemeyer, Lucas und Kallo, Josef und Heitmann, Stefan und Griebenow, Malte (2014) CHARACTERISTICS OF PEMFC OPERATION IN AMBIENT AND LOW PRESSURE ENVIRONMENT CONSIDERING THE FUEL CELL HUMIDIFICATION. CEAS Aeronautical Journal. Springer. DOI: 10.1007/s13272-014-0142-z. ISSN 1869-5582.
Werner, Claudia und Gores, Florian und Kallo , Josef und Heitmann, Stefan und Griebenow, Malte (2013) Merkmale des PEMFC-Betriebes bei Umgebungs- und Unterdruckbedingungen. In: 62. Deutscher Luft- und Raumfahrtkongress 2013. 62. Deutscher Luft- und Raumfahrtkongress 2013, 10.-12.09.2013, Stuttgart, Deutschland. Volltext nicht frei.