1. Institute of Propulsion Technology, German Aerospace Center (DLR), Müller-Breslau-Straße 8, Berlin 10623, Germany e-mail:
2. Institute of Propulsion Technology German Aerospace Center (DLR), Müller-Breslau-Straße 8, Berlin 10623, Germany
3. Institute of Propulsion Technology, German Aerospace Center (DLR), Müller-Breslau-Straße 8, Berlin 10623, Germany
4. Institute of Propulsion Technology, German Aerospace Center (DLR), Linder Höhe, Cologne 51147, Germany