Flame control in the momentum-dominated fluid dynamics region

Abstract

A combustion system includes a fuel nozzle and first and second electrodes. An electric charge is applied to a flame supported by the nozzle via the first electrode. An electrical potential applied to an aerodynamic surface of the second electrode. The electrically charged flame reacts to the electrical potential according to the respective magnitudes and polarities of the charge applied to the flame and the electrical potential applied to the aerodynamic surface. Where the polarities are the same, the flame is repelled by the aerodynamic surface, and where the polarities are in opposition, the flame is pulled into contact with the aerodynamic surface by the electrodynamic attraction.

What is claimed is: 
     
         1 . A combustion system, comprising:
 a fuel nozzle;   a voltage supply;   a first electrode coupled to the voltage supply, positioned and configured to apply an electric charge to a flame supported by the fuel nozzle; and   an aerodynamic surface coupled to the voltage supply, positioned adjacent to the fuel nozzle and having portions that vary in distance from a longitudinal axis of the fuel nozzle.   
     
     
         2 . The system of  claim 1 , wherein the fuel nozzle comprises the first electrode. 
     
     
         3 . The system of  claim 1 , wherein the voltage supply is configured to apply the electric charge having a first value to the flame via the first electrode, and to apply electrical energy having a second value to the flame via the aerodynamic surface. 
     
     
         4 . The system of  claim 3 , wherein the first value and the second value are at a same polarity. 
     
     
         5 . The system of  claim 3 , wherein the first value and the second value are at opposite polarities. 
     
     
         6 . The system of  claim 3 , wherein one of the first and second values is a ground potential. 
     
     
         7 . The system of  claim 3 , wherein the voltage supply is configured to selectively control polarities of the first and second values. 
     
     
         8 . The system of  claim 3 , comprising a second electrode coupled to the voltage supply, positioned and configured to apply electrical energy to the flame supported by the nozzle. 
     
     
         9 . The system of  claim 8 , wherein the voltage supply is configured to apply electrical energy having a third value to the flame via the second electrode. 
     
     
         10 . The system of  claim 9 , wherein the voltage supply is configured to apply the electric charge having the first value to the flame via the first electrode, and to selectively control polarities of the second and third values according to an intended effect on the flame. 
     
     
         11 . The system of  claim 8 , wherein the second electrode includes an additional aerodynamic surface. 
     
     
         12 . The system of  claim 11 , wherein the additional aerodynamic surface includes portions that vary in distance from the longitudinal axis of the fuel nozzle. 
     
     
         13 . The system of  claim 3 , wherein the aerodynamic surface is positioned and configured such that when polarities of the first and second values are opposite each other, formation of vortices directly upstream from the aerodynamic surface increases, relative to formation of vortices when the polarities of the first and second values are not opposite each other. 
     
     
         14 . The system of  claim 1 , wherein the aerodynamic surface comprises a plurality of convolutions that include the portions that vary in distance from the longitudinal axis of the fuel nozzle. 
     
     
         15 . The system of  claim 1 , wherein the aerodynamic surface is movable relative to the longitudinal axis of the nozzle. 
     
     
         16 . The system of  claim 15 , wherein the aerodynamic surface is translatable relative to the longitudinal axis of the nozzle. 
     
     
         17 . The system of  claim 15 , wherein the aerodynamic surface is rotatable relative to the longitudinal axis of the nozzle. 
     
     
         18 . The system of  claim 15 , wherein the aerodynamic surface is one of a plurality of aerodynamic surfaces that are mechanically and electrically coupled together and configured to rotate about a common axis. 
     
     
         19 . A method for controlling a flame, comprising:
 supporting a flame in a combustion volume;   applying an electrical charge to the flame;   applying a lateral bias to the flame along a length of an aerodynamic surface positioned adjacent to the flame by applying an electrical potential to the aerodynamic surface.   
     
     
         20 . The method of  claim 19 , wherein the applying a lateral bias to the flame includes applying a lateral bias to the flame toward the aerodynamic surface by applying an electrical potential having an opposite polarity from a polarity of the electrical charge. 
     
     
         21 . The method of  claim 19 , wherein the applying a lateral bias to the flame includes applying a lateral bias to the flame away from the aerodynamic surface by applying an electrical potential having a same polarity as a polarity of the electrical charge. 
     
     
         22 . The method of  claim 19 , wherein the applying a lateral bias to the flame includes applying the lateral bias to the flame substantially within a momentum-dominated fluid dynamics region of the flame. 
     
     
         23 . The method of  claim 19 , comprising varying a value of the electrical potential. 
     
     
         24 . The method of  claim 19 , comprising varying a polarity of the electrical potential, relative to a polarity of the electrical charge. 
     
     
         25 . The method of  claim 19 , wherein the applying an electrical potential comprises applying a ground potential to the aerodynamic surface. 
     
     
         26 . The method of  claim 19 , comprising increasing formation of vortices downstream from the aerodynamic surface, wherein the increasing formation of vortices includes the applying a lateral bias to the flame. 
     
     
         27 . The method of  claim 19 , wherein the supporting a flame includes emitting a fuel flow from a nozzle, the method further comprising moving the aerodynamic surface relative to a longitudinal axis of the nozzle.