A BLADE-BY-BLADE TIP CLEARANCE MEASUREMENT SYSTEM FOR GAS-TURBINE APPLICATIONS

It is difficult to make a reliable measurement of running clearance in the hostile environment over the blading of a modern gas turbine. Whe n engine manufacturers require the measurement to be made over every b lade during live engine tests, system reliability, ruggedness, and eas e of operation are of primary importance. This paper describes a tip c learance measurement system that can measure clearance over every blad e around a rotor. The measurement system concept is presented, and the system design described in detail. Commissioning of the measurement s ystem on a compressor test facility, and the results obtained are disc ussed. An analysis of system performance during the commissioning tria ls concludes the paper.