Recovery Act - Large Silicon Nitride Blisks for High-Efficiency Gas Turbines

The commercialization of ceramic gas (Brayton-cycle) turbines in the range of 50 kWe to 1.5 MWe has been a tantalizing challenge for many organizations for nearly forty years, because ceramic turbines hold the promise of operation at turbine inlet temperatures of 1400 deg C (2550 deg F) and above, at which point cycle thermal efficiencies can be very high, potentially over 50%. All efforts to date have been unsuccessful. Now, the combination of new turbine system designs, ceramics improvements, and advances in lower-cost manufacturing of largediameter silicon nitride blisks (blades plus disks) offer a meaningful opportunity for success. A totally new turbine system design approach is proposed, involving axial-flow configurations with peripheral speeds under half (below 300 m/s) of those used in many earlier turbines, thus greatly reducing steady-state stresses, and thereby enabling the use of ceramics. New potential to manufacture low-cost blisks of silicon nitride holds promise for low-cost, high-efficiency engines up to 1.5MWe and is the key breakthrough that ceramic gas turbines have needed in order to offer promise of success. The Phase 1 design and analysis feasibility studies primarily focused on Wilson TurboPower