Evaluation of preparation and combustion rig tests of an effusive cooled SiC/SiCN panel

Abstract

SiC/SiCN ceramic matrix composites (CMCs) are promising candidates for components of aero-engines. To evaluate the properties of these CMCs under realistic conditions, a quasi-flat panel with effusion cooling holes was investigated in a high pressure combustor rig. A Tyranno SA3 fabric-based SiC/SiCN composite with high strength and strain to failure was manufactured via polymer infiltration and pyrolysis process. Due to its weak matrix no fiber coating was necessary for damage tolerant behavior. The cooling holes in the panel were introduced via laser drilling. An outer coating of CVD-based SiC was finally applied for enhanced oxidation resistance. The specimen was tested in the combustor rig and the cooling effectiveness was evaluated. The microstructure of laser machined holes was studied via microscopy and energy-dispersive X-ray spectroscopy. The macrostructure was investigated via computing tomography scans before and after the combustor test. Material performances at higher temperatures were estimated via a material performance index. Local microstructure modifications were observed after laser drilling. No crack formation was observed in the CMC panels after rig tests. The measured global cooling effectiveness of 0.76 and the analytical performance evaluation demonstrate the potential benefit of SiC/SiCN materials in combustor applications.