Ceramic Composites Portend Long Turbopump Lives 931372
Use of continuous fiber reinforced ceramic matrix composites (FRCMC) for turbopump hot section components offers a number of benefits. The performance benefits of increased turbine inlet temperature are apparent and readily quantifiable. Perhaps less obvious are the potential benefits of increased component life. At nominal turbopump operating conditions, FRCMC offer increased operating temperature margin relative to conventional materials. This results in potential for significant life enhancement. Other attributes (e.g., thermal shock resistance and high cycle fatigue endurance) of FRCMC provide even greater potential to improve life and reduce maintenance requirements.
Silicon carbide (Sic) matrix composites with carbon fibers (C/SiC) do not degrade when exposed to hydrogenrich steam for 10 hours at 1200°C. This FRCMC is resistant to thermal shock transients far in excess of those anticipated for advanced, high temperature turbomachinery. Orthogonal, two-dimensional (2D), plain woven, C/SiC also does not degrade when subjected to tensile-tensile fatigue at room temperature for 4×105 cycles at 75% of the ultimate strength. Runout at >106 cycles occurs for axial specimens subjected to fully reversed, strain controlled fatigue at ambient temperature and 0.3% strain.