Advanced Research Instrumentation for Aircraft Turbomachinery

Development of advanced technology gas turbine aircraft propulsion systems has focused on performance, efficiency and durability. The resulting trend has been increased turbine inlet temperatures, more sophisticated airfoil cooling mechanisms, higher rotor speeds and stage loadings, and improved aerodynamics. This has required the development of advanced measurement technologies. Work done in four technology areas under NASA sponsorship is addressed in this paper. Small 2000°F sputtered thin film thermocouples have been developed for engine and component testing. These sensors replace conventional wire thermocouples and wire strain gages. Several types of heat flux sensors are now in use for making measurements under actual environmental conditions of combustor liner and turbine blades and vanes. Turbine blade metal surface temperatures are currently measured using scanning radiation pyrometry. Laser Doppler Velocimetry is discussed as it is used to obtain detailed intrablade velocity mappings between airfoils and in blade wakes.