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

Kurzfassung

The outflow channel of the fluidic jet reaction control element (FLE) and hence the direction of the thrust vector may be controlled by the injection of a secondary jet through one of the slits. These are located downstream the inlet nozzle in the side walls. The main medium used is gaseous nitrogen, which is supplied by a chamber. Depending on the pressure there, three different operating modes are recognized. In order to reduce development time, the DLR Euler and Navier-Stokes code FLOWer has been extended for the numerical simulation of the flow through a fluidic element. In the present work the code is verified and validated for this application. Influences from grid density, turbulence model, boundary conditions and the geometry of the external walls are investigated. The code is validated by comparing numerically obtained results with experimental data, including wall pressure and thrust measurements as well as differential interferometry photos. Numerical solutions are obtained for chamber pressures ranging from 60 to 100 bar, considering cases each with and without injection of a secondary mass flow. Furthermore, a parametric study is carried out for the secondary flow parameters.