Simulation of LOx/GH2 single coaxial injector at high pressure conditions

The numerical prediction of the processes in rocket combustion chambers is still challenging due to a variety of problems that are not completly investigated nor completly understood within computational fluid dynamics (CFD): First to mention is the accurate prediction of the jet behavior for sub- and supercritical conditions of propellents (e.\,g. liquid oxygen LOx) that influences the whole combustion process as well as the flame structure. Another challenge for the numerical method are the dissimilar length scales and material properties for the liquid and gaseous parts in combination with the chemical reactions for the LOx-GH2 combustion. In this study we use the TAU numerical flow solver for the simulation of single-injector experiments conducted at the German Aerospace Center (DLR) in Lampoldshausen. Based on experimental investigations in a windowed DLR subscale thrust chamber ``C'' (designated BKC) the numerical method in TAU for the simulation of sub- und supercritical LOx-GH2 combustion and atomization model is validated. Liquid oxygen and gaseous hydrogen have been injected through a single coaxial nozzle injector element. For validation of the numerical codes extensive measurements of OH emissions and shadowgraph images of the jet structure are available. Furthermore, wall pressure and temperature measurement data are available that are useful for the validation of the numerical framework. With this study we aim to validate an extension to the TAU flow solver that handles efficiently cryogenic fluids. This solver is able to predict the atomization and combustion processes within rocket combustion chambers at typical operating conditions. For validation we compare the numerical results for one super- and one subcritical load step measured in the experimental BKC campaign