Parametrical study on side load generation in subscale rocket nozzles

German Aerospace Center Langer Grund, Lampoldshausen 74239, Germany

Abstract

The flow separation within convergent–divergent rocket engine nozzles induces undesired side loads. As the flow separation cannot be avoided during startup and shutdown processes of the engine, the understanding of the resulting side loads is of crucial interest. To develop and validate side load models, an experimental parametrical study was conducted. The parameters of interest were the length of the separated backflow region, the wall contour angle, and the total pressure gradient during startup and shutdown processes. For this reason, three subscale models were designed and tested in five configurations. As the main side load driver, a comparably slow moving separation front, passing a long and narrow backflow region, could be identified.