Axial Diffuser Flow Control Device

Abstract

An axial diffuser for a gas turbine includes diffuser walls that define diffuser channels receiving compressor discharge air. The diffuser walls diverge in a flow direction. A flow control device is disposed in the diffuser channels and includes a plasma controller that serves to ionize airflow in the diffuser channels.

What is claimed is: 
     
         1 . An axial diffuser for a gas turbine, the axial diffuser comprising:
 diffuser walls that define diffuser channels receiving compressor discharge air, the diffuser walls diverging in a flow direction; and   a flow control device disposed in the diffuser channels, the flow control device including a plasma controller that serves to ionize airflow in the diffuser channels.   
     
     
         2 . An axial diffuser according to  claim 1 , wherein the plasma controller comprises two wires secured to the diffuser walls and an energy source providing a current between the two wires. 
     
     
         3 . An axial diffuser according to  claim 2 , wherein the energy source comprises a direct current power supply. 
     
     
         4 . An axial diffuser according to  claim 1 , wherein the plasma controller comprises first and second electrodes secured to the diffuser walls and separated by a dielectric material, and an energy source connected to the electrodes. 
     
     
         5 . An axial diffuser according to  claim 1 , wherein the plasma controller comprises an anode and a cathode secured to one of the diffuser walls, and wherein the cathode is disposed downstream of the anode. 
     
     
         6 . A flow control device cooperable with an axial diffuser in a gas turbine, the flow control device comprising a plasma controller that serves to ionize airflow through the axial diffuser. 
     
     
         7 . A flow control device according to  claim 6 , wherein the plasma controller comprises two wires secured to walls of the diffuser and an energy source providing a current between the two wires. 
     
     
         8 . A flow control device according to  claim 7 , wherein the energy source comprises a direct current power supply. 
     
     
         9 . A flow control device according to  claim 6 , wherein the plasma controller comprises first and second electrodes secured to walls of the diffuser and separated by a dielectric material, and an energy source connected to the electrodes. 
     
     
         10 . A flow control device according to  claim 6 , wherein the plasma controller comprises an anode and a cathode secured to one of the diffuser walls, and wherein the cathode is disposed downstream of the anode. 
     
     
         11 . A method of controlling flow in a gas turbine axial diffuser, the method comprising:
 positioning a flow control device in diffuser channels of the axial diffuser, the flow control device including a plasma controller; and   applying a current to the plasma controller to ionize airflow in the diffuser channels.   
     
     
         12 . A method according to  claim 11 , wherein the plasma controller includes first and second electrodes secured in the diffuser channels and separated by a dielectric material, and an energy source connected to the electrodes, the method further comprising creating an electric wind. 
     
     
         13 . A method according to  claim 12 , wherein the applying step is practiced by applying a direct current between the first and second electrodes. 
     
     
         14 . A method according to  claim 11 , wherein the positioning step is practiced by securing two wires to walls of the diffuser. 
     
     
         15 . A method according to  claim 11 , comprising altering an air flow direction in different channels based on an aerodynamic shape of the diffuser, thereby making the air flow conform to the shape of the diffuser. 
     
     
         16 . A method according to  claim 11 , comprising accelerating a decreased amount of air during reduced load on the turbine through the diffuser to thereby further control turbine performance. 
     
     
         17 . A method according to  claim 16 , comprising redirecting an amount and nature of the flow to control impingement of air on the combustion hardware.