Situ blade mounted tip gap measurement for turbines

A method for measuring gas turbine blade tip and turbine casing radial clearance gap, comprising:

• providing a gas turbine with a rotatable rotor having a turbine blade with a radially outwardly projecting tip in opposed spaced relationship with a circumscribing turbine casing, defining a gap there between;
• coupling at least one infra-red displacement sensor that is capable of generating data set of displacement relative to the circumscribing turbine casing to the turbine blade;
• coupling to the turbine blade a tilt sensor that is capable of generating a data set of blade rotational position;
• rotating the rotor so that the turbine blade tip sweeps at least a portion of the circumscribing turbine casing while generating the displacement data set with the displacement sensor and a rotational position data set with tilt sensor;
• acquiring the displacement and rotational position data sets with a data acquisition system that is coupled to the turbine blade as well as the displacement and tilt sensors;
• and
• correlating blade tip and circumscribing turbine casing radial clearance gap relative to rotational position with the displacement and rotational data sets in a data analyzer system that is coupled to the data acquisition system by a wireless communication system.

A system for measuring gas turbine blade tip and turbine casing radial clearance gap in a gas turbine having a rotatable rotor, a turbine blade coupled to the rotor with a radially outwardly projecting tip in opposed spaced relationship with a circumscribing turbine casing, defining a gap there between, the system comprising:

• at least one displacement sensor that is capable of generating data set of displacement relative to the circumscribing turbine casing, coupled to the turbine blade;
• a rotor rotational position sensor coupled to the turbine that is capable of generating data set of blade rotational position;
• a data acquisition system that is coupled to the displacement and rotational position sensors, for acquiring the displacement and rotational position data sets during rotor rotation as the turbine blade tip sweeps at least a portion of the circumscribing turbine casing;
• and
• a data analyzer system, coupled to the data acquisition system, for correlating with the displacement and rotational data sets the blade tip and circumscribing turbine casing radial clearance gap relative to rotational position.