The Application of Chemical Vapor Deposited Silicon Carbide to Radial Turbomachinery

Radial turbines have significant advantage over axial flow machines, particularly in the small sizes because of their greater stage-work capacity at higher efficiencies. To fully realize this potential, it will be necessary to develop a ceramic radial rotor capable of withstanding the severe temperatures and stresses normally encountered in a gas turbine application. This paper presents such a rotor design and the progress to date toward fabricating the component in chemical vapor deposited silicon carbide (CVD SiC). The analysis shows that even the best current material is just good enough for the simplest type turbine rotor. Thus, it is important to develop a rotor material with the potential for evolving to meet the higher performance requirements of future gas turbines. CVD SiC was selected because it is the strongest material known at the operating temperature and has the greatest potential for significant improvement.