First experimental results on the nozzle/base flow interaction for Launcher configurations

Kurzfassung

In order to achieve an improved understanding of the interaction of the nozzle flow with the base flow an experimental study on a generic model has been carried out in the DLR hypersonic wind tunnel H2K. For experimental simulations a 1:50 scaled model representing the base region of the Liquid Fly-Back Boosters (LFBB) configuration, which is one of the possible future booster options for Ariane, has been designed. To distinguish between different physical effects, the geometry of the model was kept as simple as possible, i.e. as a single nozzle configuration. The test condition was defined to reproduce the LFBB trajectory point at Mach 5.3 and 50 km altitude. This paper covers a detailed description of the experimental set up including the complex model design as well as results gained by the first experiments. The main objective of these preliminary tests was to check the experimental test concept and the instrumentation. These runs with cold nozzle flow but realistic external flow simulation were performed at several pressure ratios. Surface pressure measurements and schlieren visualization were combined to study the flow topology. The first high speed images, although at the relative low frame rate of 3 kHz, already visualized fluctuations in the flow field.