Gaseous Film Cooling Investigation in a Model Single Element GCH4-GOX Combustion Chamber

Abstract

Within the frame of a broader activity towards the use of methane as innovative propellant for rocket engines ongoing at the Institute of Space Propulsion, the efficiency of film cooling is investigated in a capacitive cooled model combustor. The combustion pressure level as well as the film applicator geometry and the film mass flow percentage are varied. The efficiency of the ambient temperature film is determined by the thermocouples installed in the copper liner along the combustion chamber axis. The fundamental dependencies from different controlling parameters are shown. Effects linked to the transient nature of the hardware are analysed. Alternative evaluation methods, which allow to deal with the transient nature of the combustion chamber are presented. Test results show the stronger influence of the blowing rate as deciding parameter for the film cooling efficiency. Increase of the blowing rate is anyhow not always connected to an improvement of the performance of the film, but a limit value could be found.