Numerical investigation of hydrogen strut injections into supersonic airflows

The influence of different injector geometries on the mixing behavior of pl anar supersonic jets is investigated. Hydrogen is injected in the flow dire ction through the blunt end of a strut. Different lip thicknesses at the in jector end induce different extents of recirculation zones. Additionally, c hanges are caused within the shock-wave/expansion fan pattern at the inject or exit that have an important influence on loss in total pressure. The acc uracy of the used numerical scheme is demonstrated for one injector geometr y by comparison with experimental data. Based on this configuration, modifi cations in lip thickness and injection Mach number are investigated numeric ally and are assessed using several calculated performance parameters. Resu lts show that the chosen lip thickness has a much stronger influence on los s in total pressure than moderate modifications in injector length and heig ht. For the very thin hydrogen jets that were investigated, the mixing effi ciency is nearly independent on injector lip thickness.