Flame position control electrodes

Abstract

A method and apparatus for stabilizing a flame in a combustion volume is disclosed. The present method and device may include a burner nozzle configured to support the flame, a halo electrode configured to anchor the flame, and electrodes disposed in top and bottom regions of the flame configured to apply voltage difference above or below the halo electrode that may assist in anchoring of the flame to the halo electrode while also controlling a shape and position of the flame. Effects of different electrical configurations within the combustion volume for stabilizing the flame are also disclosed.

What is claimed is: 
     
         1 . A combustion system, comprising:
 a burner nozzle having a longitudinal axis, positioned within a combustion volume and configured to emit a flow stream, including a mixture of fuel and oxidizer, that expands and slows at distances receding away from the burner nozzle, and to support a flame via the flow stream;   a first high-voltage power supply (HVPS); and   a first electrode operatively coupled to the first HVPS, the first electrode being configured and disposed on a diameter generally concentric with the longitudinal axis of the burner nozzle at a first distance from the burner nozzle, the first distance corresponding to a region in which the flow stream has expanded and marginally slowed, the first HVPS being configured to supply a first voltage potential to the first electrode, sufficient to charge the flame such that the charged flame is stably held on or near a surface of the first electrode.   
     
     
         2 . The combustion system of  claim 1 , wherein the first electrode has a ring torus shape disposed in a plane and having a center axis of rotation normal to the plane, wherein the center axis of rotation is about coincident with the longitudinal axis of the burner nozzle. 
     
     
         3 . The combustion system of  claim 2 , comprising an electrically resistive coating on the surface of the first electrode. 
     
     
         4 . The combustion system of  claim 2 , further including one or more additional electrodes, each operatively coupled to a respective additional HVPS. 
     
     
         5 . The combustion system of  claim 4 , wherein the one or more additional electrodes include a second electrode disposed a second distance from the burner nozzle, greater than the first distance and corresponding to a top region of the charged flame. 
     
     
         6 . The combustion system of  claim 5 , wherein the second electrode has a ring torus shape disposed on a diameter generally concentric with the longitudinal axis of the burner nozzle. 
     
     
         7 . The combustion system of  claim 5 , wherein the second electrode is configured to receive a second voltage potential, different from the first voltage potential from the respective additional HVPS of the second electrode, and thereby producing an electrical field along a length of the charged flame between the first electrode and the second electrode. 
     
     
         8 . The combustion system of  claim 5 , wherein the one or more additional electrodes include a third electrode disposed a third distance from the burner nozzle, less than the first distance and corresponding to a base region of the charged flame, the additional respective HVPS of the third electrode being configured to provide a third voltage potential to the third electrode, and to produce thereby a voltage difference between the first electrode and the third electrode. 
     
     
         9 . The combustion system of  claim 8 , wherein the first, second, and third voltage potentials are selected to produce voltage differences between each of the first, second, and third electrodes. 
     
     
         10 . The combustion system of  claim 5 , wherein the one or more additional electrodes comprise a second electrode disposed a second distance from the burner nozzle, less than the first distance and corresponding to a base region of the charged flame. 
     
     
         11 . The combustion system of  claim 6 , wherein each of the first and the one or more additional electrodes further includes a switch for independently opening and closing electrical continuity between the first and the one or more additional electrodes and the respective additional HVPS. 
     
     
         12 . The combustion system of  claim 1 , wherein the oxidizer is selected from the group consisting of oxygen in ambient air, oxygen concentrated air, oxygen, ozone, hydrogen peroxide, recycled flue gases and combinations thereof. 
     
     
         13 . The combustion system of  claim 1 , wherein the oxidizer is oxygen from ambient air. 
     
     
         14 . A combustion system, comprising:
 a burner nozzle having a longitudinal axis and configured to emit a flow stream including a mixture of fuel and oxidizer within a combustion volume, the burner nozzle being electrically coupled to a circuit ground;   a first electrode disposed a first distance from the burner nozzle corresponding to a top region of flame supported by the flow stream emitted by the burner nozzle;   a high-voltage power supply (HVPS) operatively coupled to the first electrode and configured to supply a first voltage potential to the first electrode;   a second electrode having a ring torus shape lying in a plane and having a center axis of rotation normal to the plane and about coincident with the longitudinal axis of the burner nozzle, the second electrode being disposed a second distance, less than the first distance, from the burner nozzle;   an electrical resistance operatively coupled between the second electrode and the burner nozzle, a series circuit being established between the HVPS and the circuit ground, via the first electrode, the flame, the second electrode, the electrical resistance, and the burner nozzle, the series circuit being configured to establish a second voltage potential at the second electrode on the basis of a current flowing in the circuit and the resistive value of the electrical resistance.   
     
     
         15 . The combustion system of  claim 14 , comprising a third electrode disposed a third distance, less than the second distance, from the burner nozzle, and wherein:
 the electrical resistance comprises a first resistor operatively coupled between the second electrode and the third electrode, and a second resistor operatively coupled between the third electrode and the burner nozzle; and   the series circuit is configured to establish the second voltage potential at the second electrode on the basis of the current flowing in the circuit and a sum of the resistive values of the first and second resistors; and   the series circuit is further configured to establish a third voltage potential at the third electrode on the basis of the current flowing in the circuit and the resistive value of the second resistor.   
     
     
         16 . A method for stably positioning a flame within a combustion volume, comprising the steps of:
 supporting a flame within a combustion volume by emitting into the combustion volume a flow stream, including a mixture of fuel and oxidizer, from a burner nozzle; and   operating a first high-voltage power supply (HVPS) to generate a first voltage potential; and   holding the flame to a first electrode by applying the first voltage potential to the flame and electrically attracting the flame to the first electrode.   
     
     
         17 . The method of  claim 16 , wherein the applying the first voltage potential to the flame and electrically attracting the flame to the first electrode comprises applying the first voltage potential to the first electrode. 
     
     
         18 . The method of  claim 16 , wherein the holding the flame to a first electrode comprises holding the flame to a first electrode having a ring torus shape disposed in a plane and having a center axis of rotation normal to the plane and about coincident with an axis of the burner nozzle. 
     
     
         19 . The method of  claim 16 , wherein the applying the first voltage potential to the flame and electrically attracting the flame to the first electrode comprises:
 applying the first voltage potential to a first electrode positioned a first distance from the nozzle; and   applying a second voltage potential, different from the first voltage potential, to a second electrode positioned a second distance, different than the first distance, from the burner nozzle.   
     
     
         20 . The method of  claim 19 , wherein the applying a second voltage potential to a second electrode comprises applying the second voltage potential to a second electrode having a ring torus shape, disposed on a diameter generally concentric with an axis of the burner nozzle. 
     
     
         21 . The method of  claim 19 , wherein the applying a second voltage potential to a second electrode positioned a second distance from the burner nozzle comprises applying the second voltage potential to the second electrode positioned a second distance, less than the first distance, from the nozzle. 
     
     
         22 . The method of  claim 19 , wherein:
 the applying the first voltage potential to a first electrode comprises closing a switch operatively coupled between a first voltage source and the first electrode; and   the applying a second voltage potential to a second electrode comprises closing a second switch operatively coupled between a second voltage source and the second electrode.   
     
     
         23 . The method of  claim 19 , wherein the applying a second voltage potential to a second electrode positioned a second distance from the burner nozzle comprises applying the second voltage potential to the second electrode positioned a second distance, greater than the first distance, from the nozzle. 
     
     
         24 . The method of  claim 23 , comprising:
 applying a third voltage potential to a third electrode positioned a third distance, less than the first distance, from the nozzle.   
     
     
         25 . The method of  claim 16 , wherein the first electrode is positioned a first distance from the nozzle, and wherein applying the first voltage potential to the flame and electrically attracting the flame to the first electrode comprises:
 applying the first voltage potential to a second electrode positioned a second distance, greater than the first distance, from the nozzle;   passing a first electrical current from the second electrode through the flame to the first electrode, and from the first electrode through an electrical resistance to a circuit ground; and   holding the burner at a ground potential.   
     
     
         26 . The method of  claim 25 , comprising passing a second electrical current from the first electrode through the flow stream to the burner nozzle. 
     
     
         27 . The method of  claim 25 , comprising establishing an electrical field along the flow stream between the first electrode and the burner nozzle. 
     
     
         28 . The method of  claim 27 , wherein the electrical resistance comprises first and second series resistors, the method comprising controlling a voltage potential at a third electrode positioned between the first electrode and the burner nozzle and electrically coupled to a node between the first and second series resistors by selecting relative resistance values of the first and second series resistors.