Optical Method for Real-Time Turbine Blade Tip Clearance Measurement

Monitoring and controlling blade tip clearance of high pressure turbines are important for maintaining the integrity of the engine during its operating points and life cycle. Operating the engine with minimum tip clearance provides several benefits, such as increased turbine efficiency, reduced emissions, and extended service life. Southwest Sciences proposes an innovative technology based on optical Fourier domain reflectometry for near real-time tip-clearance measurement with an accuracy of 10 micrometers or better. A simple and robust optical sensor will withstand temperatures of up to 2000 F; therefore, the method can be applied for tip-clearance measurements in turbine hot sections. The system will allow controlling multiple sensors acquiring data from different locations in the turbine with a single main unit. The Phase I effort will provide experimental evidence of the feasibility of this approach and outline the design of the Phase II prototype instrument.