Modeling and simulation of a GOX/kerosene subscale rocket combustion chamber with film cooling

Detailed knowledge on the heat transfer mechanisms is crucial for the design of reliable and efficient rocket engines. Due to the high heat loads of the combustion chamber walls and the corrosive hot gases, film cooling is often applied supplementary or even as a primary cooling technique. Nevertheless, the dominating processes determining the film effectiveness under the conditions representative for rocket combustors are still not fully understood. In context of the national research program Transregio SFB/TRR-40, TEKAN and TARES, the Institute for Flight Propulsion (LFA) of the Technische Universität München (TUM) and Airbus Defence and Space carry out experimental and numerical investigations on heat transfer and film cooling techniques at application-relevant combustion pressures and temperatures. In this paper, results from film cooling experiments and numerical simulations with liquid and transcritical kerosene films in a water-cooled GOX/kerosene rocket combustion chamber are presented. The tests have been performed at two different combustion chamber pressures and with two different throat diameters to study the influence of Reynolds and Mach number. In the numerical investigations, a major issue has been the modeling of kerosene films in sub- and transcritical state. For the modeling Airbus Defence and Space’s in-house tool, 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 propellant injection, atomization, mixing, combustion, wall heat transfer, film modeling as well as the conjugate heat transfer into the chamber wall and the cooling channels.