Heat Transport Processes of Gaseous Film Cooling in Rocket Combustion Chambers

The scope of this work comprises the experimental investigation of film cooling with gaseous hydrogen (GH2) in the vicinity of the faceplate and the cylindrical region of a subscale GH2/LOx-rocket combustion chamber. The experimental setup consists of a novel experimental combustion chamber with a rectangular cross section and interchangeable measurement devices, allowing for optical access and simultaneous measurement of wall heat fluxes and combustion chamber pressures. A multi-injector faceplate prevents window film cooling from interacting with the investigated near-wall cooling film and injector reacting flow. With the use of a novel patented calorimetric measurement device, 2D wall heat fluxes were evaluated. Based on these data, a new correlation for the film cooling efficiency is elaborated and verified for operating points in the supercritical, transcritical, and subcritical regimes of oxygen. Furthermore, the influence of LF instabilities on wall heat input is experimentally investigated and presented. All in all, this work provides a wide and accurate database for validation of numerical tools and gives insight into the processes of film cooling in a rocket combustion chamber.