Experimental and numerical film cooling investigations in a GOX/ kerosene rocket combustion chamber

Detailed knowledge on heat transfer is crucial for the design of reliable and efficient rocket engines. Due to high heat loads and chemical attack of the combustion chamber walls, film cooling is often applied supplementary for high pressure regenerative cooled combustion chambers or as a primary cooling technique for low pressure thrusters. Nevertheless, dominating processes determining the film effectiveness under conditions typical for rocket combustors are still not completely understood. The LFA operates a rocket combustion test facility which allows investigations on heat transfer at relevant combustion pressures and temperatures. In the context of a national research program SFB TRR 40 the LFA conducts experiments on film cooling, while Airbus Defence&Space carries out associated numerical investigations. In this paper results from film cooling experiments with kerosene film in a water cooled GOX/ kerosene rocket combustion chamber are presented. The tests have been performed at two different combustion pressures and with two different nozzle diameters to study the influence of the Mach number. In the numerical investigations, one major issue has been the modeling of kerosene films in sub- and transcritical state. For the modeling Airbus Defence&Space’s in-house code Rocflam-II has been applied. The main goal of Rocflam-II is to provide a tool package for the simulation of a wide range of rocket combustion devices, validated against experimental data. This includes the modeling of injection, atomization, mixing, combustion, wall heat transfer, film cooling as well as additional water cooling simulated by 1D or 3D conjugate heat transfer.