Laser Application in Metrology - Measurement of Turbine Rotor Tip Shroud Clearance

This paper describes the application and the design of the Rotor Shroud Gap LASER Inspection Gauge (RSGLIG). The gauge can measure the turbine rotor tip shroud clearances (gaps) with a high degree of accuracy, repeatability and in a fraction of the time required by manual methods. Gas turbine blade tip shrouds provide the required airfoil twist restraint for proper airfoil aerodynamic position and vibration damping. The size of gaps is essential for proper engine operation. Smaller gaps minimize vibratory stresses in many blade applications which can result in increased rotor life.