Progress on the Advanced Turbine Technology Applications Project (ATTAP)

This technology project, sponsored by the U.S. Department of Energy, is intended to advance the technological readiness of the ceramic automotive gas turbine engine. Of the several technologies requiring development before such an engine becomes a commercial reality, structural ceramic components represent the greatest technical challenge, and are the prime project focus. The ATTAP aims at developing and demonstrating such ceramic components that have a potential for: (1) competitive automotive engine life cycle cost and (2) operating for 3500 hr in a turbine engine environment at turbine inlet temperatures up to 1371°C (2500°F). Allison is addressing the ATTAP goal using internal technical resources, an extensive technology and data base from General Motors (GM), technical resources from several subcontracted domestic ceramic suppliers, and supporting technology developments from Oak Ridge and other federal programs. The development activities have resulted in the fabrication and delivery of numerous ceramic engine components, which have been characterized through laboratory evaluation, cold spin testing, hot rig testing, and finally through engine testing as appropriate. These component deliveries are the result of the ATTAP design/process development/fabrication/characterization/test cycles. Ceramic components and materials have been characterized in an on-going program using nondestructive and destructive techniques. So far in ATTAP, significant advancements include: • evolution of a correlated design procedure for monolithic ceramic components • evolution of materials and processes to meet the demanding design and operational requirements of high temperature turbines • demonstration of ceramic component viability through thousands of hours of both steady-slate and transient testing while operating at up to full design speed, and at turbine inlet temperatures up to 1371°C (2500°F) • completion of hundreds of hours of durability cyclic testing utilizing several “all ceramic” gasifier turbine assemblies • demonstration of ceramic rotor survivability under conditions of extreme foreign object ingestion, high speed turbine tip rub, severe start-up transients, and a very demanding durability cycle In addition to the ceramic component technology, progress has been made in the areas of low emission combustion technology and regenerator design and development.