Blade tip clearance measurement sensor and method for gas turbine engines

Abstract

An electromagnetic field sensor assembly for blade tip clearance measurement in a gas turbine engine is disclosed that includes a ceramic sensor body, a multi-layered wire coil wound about a distal end portion of the sensor body for producing an electromagnetic field, a ceramic well enclosing the sensor body and the coil, and a metallic housing surrounding the well and having an open distal end.

1 . An electromagnetic field sensor assembly comprising:
 a) a ceramic sensor body;   b) a wire coil wound about a distal end portion of the ceramic sensor body for producing an electromagnetic field, wherein the wire coil is formed from a platinum group metal or an alloy thereof;   c) a ceramic well enclosing the ceramic sensor body and the wire coil; and   d) a metallic housing surrounding a periphery of the ceramic well and having an open distal end.   
   
   
       2 . An electromagnetic field sensor assembly as recited in  claim 1 , wherein the sensor body is formed from aluminum oxide. 
   
   
       3 . An electromagnetic field sensor assembly as recited in  claim 1 , wherein the sensor body is rigidly mounted within the ceramic well. 
   
   
       4 . An electromagnetic field sensor assembly as recited in  claim 1 , wherein the wire coil is formed from an oxide dispersion strengthened platinum group metal or alloy thereof. 
   
   
       5 . An electromagnetic field sensor assembly as recited in  claim 1 , wherein the wire coil is formed from a ceramic coated wire. 
   
   
       6 . An electromagnetic field sensor assembly as recited in  claim 1 , wherein the wire coil is formed by plural layers, each layer having a plurality of turns. 
   
   
       7 . An electromagnetic field sensor assembly as recited in  claim 1 , wherein the distal end portion of the sensor body has an annular recess for accommodating the wire coil. 
   
   
       8 . An electromagnetic field sensor assembly as recited in  claim 7 , wherein the wire coil is anchored to the sensor body within the annular recess by cement. 
   
   
       9 . An electromagnetic field sensor assembly as recited in  claim 1 , wherein the ceramic well is formed from aluminum oxide. 
   
   
       10 . An electromagnetic field sensor assembly as recited in  claim 1 , wherein the ceramic well is a sealed enclosure. 
   
   
       11 . An electromagnetic field sensor assembly as recited in  claim 1 , wherein the metallic housing is formed with cooling channels. 
   
   
       12 . An electromagnetic field sensor assembly as recited in  claim 1 , further comprising a metal transition member joining the ceramic well to the metallic housing. 
   
   
       13 . An electromagnetic field sensor assembly as recited in  claim 1 , further comprising a cable adapter joined to a proximal end portion of the metallic housing. 
   
   
       14 . An electromagnetic field sensor assembly as recited in  claim 1 , wherein a pair of coaxial cable assemblies are joined to the cable adapter for connection with the coil. 
   
   
       15 . An electromagnetic field sensor assembly as recited in  claim 14 , wherein cable lead wires are joined to center conductors of the coaxial cables for connection to opposite end of the coil. 
   
   
       16 . An electromagnetic field sensor assembly as recited in  claim 15 , wherein the center conductor of each coaxial cable is formed from two different conductor materials connected in series to one another. 
   
   
       17 . An electromagnetic field sensor assembly as recited in  claim 1 , wherein the sensor assembly includes two sensor bodies each having a wound coil associated with a distal end portion thereof. 
   
   
       18 . An electromagnetic field sensor assembly as recited in  claim 17 , wherein the distal end portions of the two sensor bodies are axially off-set from one another.