Method and Apparatus for Monitoring Blade Vibration With An Imaging Fiber Optic Ribbon Probe

In a turbine engine including a blade structure comprising a plurality of blades having blade tip target portion and supported for rotation, and a casing surrounding the blade structure, a method of providing a blade vibration monitor comprising:

• providing an illumination conduit connected to a light source and emitting a line of light into the casing to define an axially elongated image from the illumination conduit;
• passing the blade tip target portions along a path of travel through locations corresponding to the axially elongated projected image and forming reflected light images at locations on the blade tip target portions to define blade passing events;
• receiving the reflected light images at a receptor end of an imaging conduit defined by a plurality of optical fibers forming a receptor array, the reflected light corresponding to a plurality of locations along the axially elongated projected image as each blade tip target portion moves past the line of light;
• conveying the reflected light images through the imaging conduit from the receptor array to an imaging array at an imaging end of the imaging conduit;
• and
• imaging the reflected light images from the imaging array onto a sensor array for identification of axial and tangential locations of at least one predetermined point on the blade tip target portions.

In a turbine engine including a blade structure comprising a plurality of blades having blade tip target portions, and a casing surrounding the blade structure, a method of providing a blade vibration monitor comprising:

• continuously winding a strand of optical fiber about a support structure, forming a plurality of windings in contact with each other;
• adhering the plurality of windings to one another along a predetermined length of the windings to define an adhered section of optical fibers;
• severing the adhered section of optical fibers transverse to the length of the optical fibers at a location intermediate the ends of the predetermined length to form severed ends, one of the severed ends defining a receptor end;
• locating the receptor end adjacent to an interior portion of the casing;
• and
• locating an imaging end of the optical fibers, opposite the receptor end, at a processor for detecting light received at the receptor end.