The COMPERE project (COMPortement des Ergols dans les Reservoirs/Behavior of Propellants in Tanks) aims to develop one or more physical and numerical models to predict the propellant behavior in tanks. The liquid in the tank is subjected to varying levels of acceleration and heat fluxes.

The project aims to understand and model physical phenomena which occur in Ariane launcher tanks during different flight phases: propulsive phase, thrust decay, ballistic phase, settling of propellants before reignition, reignition of the engine.

The final goal of this project is to improve the determination of the following parameters: the position of the propellants (for engine reignition), the pressures and temperatures in the tanks (handling of pressure and engine reignition), the stresses on the structures (guidance and material resistance), and the non-consumable masses (performance).

The COMPERE project comprises of a group of experts in France and Germany. The members are the French and the German Space Agency (CNES, DLR), the industry (EADS, Air Liquide) and research organisations: IMFT Toulouse, LEGI Grenoble, ONERA Paris and Toulouse, University of Erlangen and University of Bremen (ZARM).

The contribution of ZARM is to perform short term microgravity experiments. The drop tower experiments focus on capillary phenomena at isothermal and non-isothermal conditions. The experiments are related to the original situation, optimized for applicability and functional demonstration. The experimental results are used as benchmarks for the validation of commercial CFD code's.