Plasma Clearance Controlled Compressor

Abstract

A plasma leakage flow control system for a compressor is disclosed, comprising a circumferential row of compressor blades, an annular casing surrounding the tips of the blades, located radially apart from the tips of the blades and at least one annular plasma generator located on the annular casing. The annular plasma generator comprises an inner electrode and an outer electrode separated by a dielectric material. A gas turbine engine having a plasma leakage flow control system further comprises an engine control system which controls the operation of the annular plasma generator such that the blade tip leakage flow can be changed.

1 . A compressor blade tip leakage flow control system comprising:
 an annular casing surrounding a row of compressor blades having blade tips; and   at least one annular plasma generator located radially outwardly and apart from the blade tips.   
     
     
         2 . A system according to  claim 1  wherein the plasma generator is mounted to the casing. 
     
     
         3 . A system according to  claim 1  wherein the plasma generator comprises a radially inner electrode and a radially outer electrode separated by a dielectric material. 
     
     
         4 . A system according to  claim 3  further comprising an AC power supply connected to the inner electrode and the outer electrode to supply a high voltage AC potential to the electrodes. 
     
     
         5 . A system according to  claim 1  further comprising a controller that turns the plasma generator on and off as needed to change blade tip effective clearance of a compressor rotor stage. 
     
     
         6 . A compressor blade tip leakage flow control system comprising:
 a plurality of shrouds surrounding a row of blades having blade tips  46 ; and   at least one annular plasma generator located radially outwardly and apart from the blade tips.   
     
     
         7 . A system according to  claim 6  wherein the plasma generator is mounted to a shroud. 
     
     
         8 . A compressor comprising:
 a rotor having a circumferential row of blades;   a casing surrounding the row of blades located radially apart from the tips of the blades; and   a system for controlling the leakage flow between the blade tips and the casing having at least one annular plasma generator located on the casing.   
     
     
         9 . A compressor comprising:
 a rotor having a circumferential row of blades;   a plurality of shrouds surrounding the row of blades located radially apart from the tips of the blades; and   a system for controlling the leakage flow between the blade tips and the casing having at least one annular plasma generator located on the casing.   
     
     
         10 . A gas turbine engine comprising:
 a compressor having a circumferential row of blades;   a casing surrounding the tips of the blades, located radially apart from the tips of the blades;   a system for controlling the leakage flow between the blade tips and the casing having at least one annular plasma generator located on the casing.   
     
     
         11 . A gas turbine engine according to  claim 10  further comprising:
 an engine control system which controls the operation of the plasma generator such that the leakage flow between the blade tips and the casing is reduced.   
     
     
         12 . A gas turbine engine according to claim wherein the annular plasma generator comprises an inner electrode, an outer electrode and a dielectric material. 
     
     
         13 . A gas turbine engine according to  claim 12  wherein the dielectric material is disposed in a radially inwardly facing surface of the casing. 
     
     
         14 . A gas turbine engine according to  claim 10  wherein the annular plasma generator is located in a groove in the casing. 
     
     
         15 . A gas turbine engine according to  claim 10  comprising a plurality of annular plasma generators located axially apart. 
     
     
         16 . A gas turbine engine according to  claim 10  further comprising a plurality of discrete plasma generators arranged circumferentially apart. 
     
     
         17 . A gas turbine engine according to  claim 10  wherein the annular plasma generator is located on a surface located radially apart from the blade tip. 
     
     
         18 . A gas turbine engine comprising:
 a compressor having a circumferential row of blades;   a plurality of shroud segments arranged circumferentially and located radially apart from the tips of the blades;   a system for controlling the leakage flow between the blade tips and the shroud segments having at least one annular plasma generator located on the shroud segments.   
     
     
         19 . A gas turbine engine according to  claim 18  wherein the annular plasma generator is located on a surface located radially apart from the blade tip. 
     
     
         20 . A gas turbine engine according to  claim 18  further comprising a plurality of discrete plasma generators arranged circumferentially apart.