Numerical Investigations of the Flow through a Fluidic Jet Reaction Control Element

Kurzfassung

The planar fluidic jet reaction control element (FLE), which is the subject of the present work, has been designed and built for test purposes. Gaseous nitrogen is used as the main medium, which is supplied to the main chamber. The flow is supersonically overexpanded in the deverging section of the nozzle and can be directed to one of the two exit channels by injection of a secondary mass flow of air through the respective slit.Depending on the chamber pressure, different operating modes exist. Since the conduction of experiments takes a considerable amount of time, especially for parametric studies, the numerical simulation of the flow through a fluidic element is investigated in the present work. For this purpose, the DLR Euler- and Navier-Stokes-code FLOWer has been extended by the required boundary conditions and the improved AUSM-scheme for the spatial discretization for the computation of hypersonic configurations with strong shocks. In order to gain reliable results the code is verified for the application to fluidic elements, considering grid density, turbulence model, boundary conditions and the modeling of the outer element geometry. The code validation is carried out by comparing the numerical solutions to the experimental results mentioned above. Numerical solutions are obtained for a variety of chamber pressures, each with and without injection of a secondary mass flow. Code verification and validation provide the base for a parametric study performed for the secondary flow parameters.