Gas turbine with extended turbine blade stream adhesion

Abstract

A gas turbine may include turbine blades configured to improve stream adhesion by selectively attracting or reducing repulsion of charged particles carried by a combustion gas stream.

1 . A gas turbine, comprising:
 a combustor configured to output a combustion gas stream at least intermittently or periodically including charged particles having a first sign; and   a turbine configured to receive the combustion gas stream and including at least one turbine stage having turbine blades, each turbine blade of the at least one stage including:
 a repelling surface configured to be at least intermittently or periodically held or driven to a repelling voltage having a polarity the same as the charged particles having the first sign, 
 an adhesion surface configured to be at least intermittently or periodically held, driven, or in equilibrium to an adhesion voltage or charge having lower magnitude than or opposite polarity from the repelling voltage, and 
 an air channel configured to deliver film-cooling air adjacent to the repelling surface. 
   
     
     
         2 . (canceled) 
     
     
         3 . The gas turbine of  claim 1 , wherein the repelling surface is configured to repel the combustion gas stream by Coulombic repulsion; and
 wherein the film-cooling air occupies a volume adjacent to the repelling surface between the repelling surface and the combustion gas stream.   
     
     
         4 . The gas turbine of  claim 1 , wherein the adhesion surface is configured to apply at least reduced Coulombic repulsion on the combustion gas stream compared to the repelling surface. 
     
     
         5 . The gas turbine of  claim 1 , wherein the adhesion surface is configured to apply Coulombic attraction to the combustion gas stream. 
     
     
         6 . The gas turbine of  claim 1 , wherein the adhesion surface includes a spanwise variation in applied voltage, charge, or area configured to promote streamwise vortex generation. 
     
     
         7 . The gas turbine of  claim 1 , further comprising:
 a voltage source operatively coupled to the adhesion surface and configured to provide the adhesion voltage to the adhesion surface.   
     
     
         8 . The gas turbine of  claim 1 , wherein the adhesion surface is configured as an electrical shield to shield the combustion gas stream from the repelling voltage. 
     
     
         9 . The gas turbine of  claim 1 , wherein the adhesion surface includes is shaped to occupy a void defined by the repelling surface. 
     
     
         10 . The gas turbine of  claim 1 , wherein the adhesion surface further comprises:
 an electrical insulator adjacent to one or more voids defined by the repelling surface; and   an electrical conductor or semiconductor adjacent to the electrical insulator.   
     
     
         11 . The gas turbine of  claim 1 , wherein the adhesion surface further comprises:
 in a recess or void defined by the repelling surface, an electrically insulating material; and   in a recess or void defined by the electrically insulating material, an electrically conductive or semiconductive adhesion electrode.   
     
     
         12 . The gas turbine of  claim 11 , wherein the electrically conductive or semiconductive adhesion electrode is configured to be in charge equilibrium or pseudo-equilibrium with the charged combustion gas stream. 
     
     
         13 . The gas turbine of  claim 12 , wherein the electrically conductive or semiconductive adhesion electrode is configured to be charged to an average voltage lower in magnitude than an average of the turbine blade repelling voltage. 
     
     
         14 . The gas turbine of  claim 12 , wherein at least one of the sign of the charged particles or the concentration of the charged particles is modulated according to a desired equilibrium or pseudo-equilibrium voltage. 
     
     
         15 . The gas turbine of  claim 1 , wherein the adhesion surface comprises at least a flow rearward portion of a low pressure side of the turbine blade. 
     
     
         16 . The gas turbine of  claim 15 , wherein the repelling surface includes substantially the remainder of the surface of the turbine blade. 
     
     
         17 . The gas turbine of  claim 1 , wherein the repelling surface includes at least a flow forward portion of a low pressure side of the turbine blade and at least a portion of a high pressure side of the turbine blade. 
     
     
         18 . The gas turbine of  claim 1 , further comprising:
 a gas turbine controller, configured to cause modulation of at least one of a sign or concentration of charged particles in the combustion gas stream.   
     
     
         19 . The gas turbine of  claim 18 , wherein the gas turbine controller is configured to select the modulation to cause a selected equilibrium voltage carried by the adhesion surface. 
     
     
         20 . The gas turbine of  claim 1 , further comprising:
 a gas turbine controller configured to apply a substantially constant or modulated adhesion voltage to the adhesion surface of the turbine blade.   
     
     
         21 . The gas turbine of  claim 1 , wherein each turbine blade further comprises:
 a first air channel configured to deliver film-cooling air through slots or holes proximate a flow forward edge of the repelling surface.   
     
     
         22 . The gas turbine of  claim 21 , wherein each turbine blade further comprises:
 a second air channel configured to deliver cooling air through slots or holes proximate the adhesion surface.   
     
     
         23 . The gas turbine of  claim 22 , wherein the adhesion surface includes a spanwise variation in area with regions having relatively high area and regions having relatively low area; and
 wherein the slots or holes proximate the adhesion surface are aligned with or preferentially distributed near the regions having relatively low area and are configured to impart upward momentum on the combustion gas stream and on film-cooling air flowing over the slots or holes;   whereby the slots or holes proximate the adhesion surface and the spanwise variation in area of the adhesion surface are configured to cooperate to promote streamwise vortex generation.   
     
     
         24 . The gas turbine of  claim 23 , further comprising:
 a charge source configured to insert charged particles having the first sign into the second air channel at least when the charged particles having the first sign in the combustion gas are proximate the turbine blade.   
     
     
         25 . The gas turbine of  claim 22 , wherein the adhesion surface includes a spanwise variation in area include regions having relatively high area and regions having relatively low area; and
 wherein the slots or holes proximate the adhesion surface are aligned with or preferentially distributed near the regions having relatively high area.   
     
     
         26 . The gas turbine of  claim 25 , further comprising:
 electrical insulation to electrically isolate the second air channel from portions of the turbine blade carrying the repelling voltage; and   a charge source configured to insert charged particles having a second sign opposite in polarity to the first sign into the second air channel at least when the charged particles having the first sign in the combustion gas are proximate the turbine blade;   whereby the charged particles having the second sign flowing through slots or holes proximate the adhesion surface and the spanwise variation in area of the adhesion surface are configured to cooperate to promote streamwise vortex generation.   
     
     
         27 . The gas turbine of  claim 1 , further comprising:
 an electrode located upstream of the turbine configured to be driven to a voltage sufficient to undergo corona discharge and at least intermittently or periodically add charged particles having the first sign or a second sign different than the first sign to the combustion gas stream.   
     
     
         28 . The gas turbine of  claim 1 , wherein the combustor is configured to burn a fuel containing an additive to increase the production of the charged particles having the first sign. 
     
     
         29 . A method of operating a gas turbine, comprising:
 providing a combustion gas stream at least intermittently or periodically carrying charged particles having a first sign;   converting thermodynamic energy to rotational energy with turbine blades;   at least intermittently or periodically applying Coulombic repulsion to the charged particles from a repelling portion of each turbine blade by applying a repelling voltage to the repelling portion; and   at least intermittently or periodically applying reduced Coulombic repulsion from or increased Coulombic attraction to an adhesion portion of each turbine blade surface by at least one of shielding the Coulombic repulsion caused by the repelling voltage or by applying an adhesion voltage to the adhesion portion of the turbine blade surface.   
     
     
         30 . The method of operating a gas turbine of  claim 29 , further comprising:
 delivering film-cooling gas adjacent to at least the repelling portion.   
     
     
         31 . The method of operating a gas turbine of  claim 30 , wherein the Coulombic repulsion does not apply a force directly to the film-cooling gas. 
     
     
         32 . The method of operating a gas turbine of  claim 30 , wherein the film-cooling gas is caused to preferentially stream adjacent to the repelling portion of the turbine blade responsive to the Coulombic repulsion of the charged particles in the combustion gas stream. 
     
     
         33 . The method of operating a gas turbine of  claim 29 , wherein at least intermittently or periodically applying reduced Coulombic repulsion from or Coulombic attraction to the adhesion portion of each turbine blade surface includes applying a spanwise variation in voltage of the adhesion portion. 
     
     
         34 . The method of operating a gas turbine of  claim 29 , wherein at least intermittently or periodically applying reduced Coulombic repulsion from or Coulombic attraction to an adhesion portion of each turbine blade surface includes applying a spanwise variation in charge carried by the adhesion surface. 
     
     
         35 . The method of operating a gas turbine of  claim 29 , wherein the adhesion portion includes a spanwise variation in area; and
 wherein at least intermittently or periodically applying reduced Coulombic repulsion from or Coulombic attraction to an adhesion portion of each turbine blade surface includes applying a spanwise variation in repelling voltage responsive to the spanwise variation in adhesion area.   
     
     
         36 . The method of operating a gas turbine of  claim 29 , wherein at least intermittently or periodically applying reduced Coulombic repulsion from or Coulombic attraction to an adhesion portion of each turbine blade surface includes at least intermittently or periodically applying a spanwise varying reduced Coulombic repulsion from or Coulombic attraction to an adhesion portion of each turbine blade surface. 
     
     
         37 . The method of operating a gas turbine of  claim 36 , wherein the spanwise variation in reduced Coulombic repulsion from or Coulombic attraction to the adhesion portion further cooperates with an aerodynamic response of each turbine blade to cause streamwise vortices to form proximate a flow rearward portion of each turbine blade. 
     
     
         38 . The method of operating a gas turbine of  claim 37 , wherein the streamwise vortices correspond to a spatially periodic spanwise increase in adhesion of the combustion gas to each turbine blade. 
     
     
         39 . The method of operating a gas turbine of  claim 29 , wherein providing a combustion gas stream at least intermittently or periodically carrying charged particles having a first sign includes modulating charged particle concentration or charged particle concentration and sign; and
 wherein applying a repelling voltage to the repelling portion of each turbine blade includes modulating the repelling voltage synchronously with the modulated charged particle concentration or charged particle concentration and sign proximate each turbine blade.   
     
     
         40 . The method of operating a gas turbine of  claim 39 , wherein at least intermittently or periodically applying reduced Coulombic repulsion from or a Coulombic attraction to the adhesion portion of the turbine blade surface includes maintaining a time-averaged equilibrium or pseudo-equilibrium with the modulated charged particle concentration or charged particle concentration and sign in the combustion gas. 
     
     
         41 . The method of operating a gas turbine of  claim 39 , wherein at least intermittently or periodically applying reduced Coulombic repulsion from or a Coulombic attraction to the adhesion portion of the turbine blade surface includes holding the adhesion portion of the turbine blade surface at ground or modulating the adhesion portion of the turbine blade surface to one or more voltages opposite in sign from the combustion gas charge proximate the turbine blade. 
     
     
         42 . The method of operating a gas turbine of  claim 39 , wherein at least intermittently or periodically applying reduced Coulombic repulsion from or a Coulombic attraction to the adhesion portion of the turbine blade surface includes modulating a voltage carried by the adhesion portion of the turbine blade surface inversely with a combustion gas charge concentration proximate the turbine blade. 
     
     
         43 . The method of operating a gas turbine of  claim 29 , wherein at least intermittently or periodically applying Coulombic repulsion to the charged particles from the repelling portion of the turbine blade surface includes modulating the repelling portion of the turbine blade surface to one or more voltages synchronously with a charge concentration or charge concentration and sign in the combustion gas proximate the turbine blade. 
     
     
         44 . The method of operating a gas turbine of  claim 43 , wherein the charged particles in the combustion gas stream proximate the turbine blade and the repelling voltage are the same sign; and
 wherein the repelling voltage is varied synchronously and inversely with the charged particle concentration.   
     
     
         45 . The method of operating a gas turbine of  claim 43 , wherein the charged particles in the combustion gas stream proximate the turbine blade and the repelling voltage are opposite signs; and
 wherein the repelling voltage is varied synchronously with the charged particle concentration.   
     
     
         46 . The method of operating a gas turbine of  claim 29 , further comprising:
 delivering first film-cooling gas through slots or holes proximate a flow forward edge of the repelling portion.   
     
     
         47 . The method of operating a gas turbine of  claim 29 , further comprising:
 delivering second gas through slots or holes proximate the adhesion portion.   
     
     
         48 . The method of operating a gas turbine of  claim 47 , wherein the adhesion portion includes a spanwise variation in area with regions having relatively high area and regions having relatively low area;
 wherein the slots or holes proximate the adhesion portion are aligned with or preferentially distributed near the regions having relatively low area; further comprising:   imparting upward momentum on the combustion gas stream flowing over the slots or holes proximate the adhesion surface to cooperate with the spanwise variation in area of the adhesion portion to promote streamwise vortex generation.   
     
     
         49 . The method of operating a gas turbine of  claim 48 , further comprising:
 inserting charged particles having the first sign into the second gas at least when the charged particles having the first sign in the combustion gas are proximate the turbine blade.   
     
     
         50 . The method of operating a gas turbine of  claim 47 , wherein the adhesion surface includes a spanwise variation in area include regions having relatively high area and regions having relatively low area; and
 wherein delivering the second gas includes delivering the second gas through the slots or holes proximate the adhesion portion that are aligned with or preferentially distributed near the regions having relatively high area.   
     
     
         51 . The method of operating a gas turbine of  claim 50 , further comprising:
 inserting charged particles having a second sign opposite in polarity from the first sign into the second gas at least when the charged particles having the first sign in the combustion gas are proximate the turbine blade, the insertion of charged particles cooperating with the spanwise variation in area of the adhesion surface to promote streamwise vortex generation.   
     
     
         52 . The method for operating a gas turbine of  claim 29 , further comprising:
 driving an electrode upstream of the turbine blades to a sufficient voltage to achieve corona discharge.   
     
     
         53 . The method for operating a gas turbine of  claim 29 , further comprising:
 combusting a fuel containing an additive to produce the combustion gas stream, the additive being selected to increase a number density of the charged particles.   
     
     
         54 . A turbine blade, comprising:
 a repelling surface configured to be at least intermittently or periodically held or driven to a repelling voltage; and   an adhesion surface configured to be at least intermittently or periodically held, driven, or in equilibrium to an adhesion voltage or charge having lower magnitude than or opposite polarity from the repelling voltage.   
     
     
         55 . The turbine blade of  claim 54 , further comprising a gas channel configured to deliver film-cooling gas adjacent to at least the repelling surface. 
     
     
         56 . The turbine blade of  claim 55 , wherein the repelling surface is configured to repel a combustion gas stream by Coulombic repulsion; and
 wherein the gas channel is configured to deliver the film-cooling gas to a volume adjacent to the repelling surface between the repelling surface and the combustion gas stream.   
     
     
         57 . The turbine blade of  claim 54 , wherein the adhesion surface further comprises:
 an electrical insulator disposed adjacent to the repelling surface; and   an electrical conductor or semiconductor disposed adjacent to the electrical insulator.   
     
     
         58 . The turbine blade of  claim 57 , wherein the adhesion surface further comprises:
 a second electrical insulator or semiconductor disposed over the electrical conductor or semiconductor.   
     
     
         59 . The turbine blade of  claim 57 , wherein the electrical conductor or semiconductor is configured to electrically shield a combustion gas stream from the repelling surface. 
     
     
         60 . The turbine blade of  claim 57 , wherein the electrical conductor or semiconductor is configured to apply at least reduced Coulombic repulsion to a combustion gas stream compared to the repelling surface. 
     
     
         61 . The turbine blade of  claim 54  wherein the adhesion surface is configured to apply at least reduced Coulombic repulsion on a combustion gas stream compared to the repelling surface. 
     
     
         62 . The turbine blade of  claim 54 , wherein the adhesion surface is configured to apply Coulombic attraction to a combustion gas stream. 
     
     
         63 . The turbine blade of  claim 54 , wherein the adhesion surface is configured to support a spanwise variation in applied voltage or charge. 
     
     
         64 . The turbine blade of  claim 54 , wherein the adhesion surface includes a spanwise variation in area. 
     
     
         65 . The turbine blade of  claim 54 , further comprising:
 an electrical lead operatively coupled to the adhesion surface, the electrical lead being configured to conduct a voltage to at least a portion of the adhesion surface.   
     
     
         66 . The turbine blade of  claim 54 , wherein the adhesion surface is shaped to occupy a void defined by the repelling surface. 
     
     
         67 . The turbine blade of  claim 54 , wherein the adhesion surface further comprises:
 in a recess or void defined by the repelling surface, and electrically insulating material; and   in a recess or void defined by the electrically insulating material, an electrically conductive or semiconductive adhesion electrode.   
     
     
         68 . The turbine blade of  claim 67 , wherein the electrically conductive or semiconductive adhesion electrode is configured to be in charge equilibrium or pseudo-equilibrium with a charged combustion gas stream. 
     
     
         69 . The turbine blade of  claim 68 , wherein the electrically conductive or semiconductive adhesion electrode is configured to be charged to an average voltage lower in magnitude than an average of a turbine blade repelling voltage. 
     
     
         70 . The turbine blade of  claim 54 , wherein the adhesion surface comprises at least a flow rearward portion of a low pressure side of the turbine blade. 
     
     
         71 . The turbine blade of  claim 70 , wherein the repelling surface includes substantially the remainder of the surface of the turbine blade. 
     
     
         72 . The turbine blade of  claim 54 , wherein the repelling surface includes at least a flow forward portion of a low pressure side of the turbine blade and at least a portion of a high pressure side of the turbine blade. 
     
     
         73 . The turbine blade of  claim 54 , further comprising:
 a first gas channel configured to deliver film-cooling gas through slots or holes proximate a flow forward edge of the repelling surface.   
     
     
         74 . The turbine blade of  claim 73 , further comprising:
 a second gas channel configured to deliver cooling gas through slots or holes proximate the adhesion surface.   
     
     
         75 . The turbine blade of  claim 74 , wherein the adhesion surface includes a spanwise variation in area with regions having relatively high area and regions having relatively low area; and
 wherein the slots or holes proximate the adhesion surface are aligned with or preferentially distributed near the regions having relatively low area and are configured to impart upward momentum on a combustion gas stream and on film-cooling air flowing over the slots or holes.   
     
     
         76 . The turbine blade of  claim 75 , further comprising:
 a charge source configured to at least intermittently or periodically insert charged particles having a first sign into the second gas channel.   
     
     
         77 . The turbine blade of  claim 74 , wherein the adhesion surface includes a spanwise variation in area include regions having relatively high area and regions having relatively low area; and
 wherein the slots or holes proximate the adhesion surface are aligned with or preferentially distributed near the regions having relatively high area.   
     
     
         78 . The turbine blade of  claim 77 , further comprising:
 electrical insulation to electrically isolate the second air channel from portions of the turbine blade carrying the repelling voltage.   
     
     
         79 . The turbine blade of  claim 78 , further comprising:
 a charge source configured to insert charged particles having a second sign opposite in polarity from the repelling voltage at least intermittently or periodically.   
     
     
         80 . The turbine blade of  claim 74 , wherein the adhesion surface includes a plurality of discontinuous regions.