Method for injecting a hydrogen-air mixture for a turbine engine burner

Abstract

An injection method, for an injection device in a combustion chamber of an aircraft turbine engine, said injection device comprising an internal channel surrounded by an external annular channel, said channels leading into said combustion chamber of the gas turbine, the method including injecting a gaseous hydrogen/air mixture having a greater hydrogen richness level than the stoichiometric amount into said internal channel and injecting air into the external annular channel so as to produce, at the outlet of the internal channel, a first flame front resulting from rich combustion surrounded by a second flame front resulting from lean combustion.

1 . An injection method, for an injection device in a combustion chamber of an aircraft turbine engine, said injection device comprising an internal channel surrounded by an external annular channel, said channels leading into said combustion chamber of said aircraft turbine engine, the method comprising:
 an injection of a gaseous hydrogen/air mixture having a greater hydrogen richness level than the stoichiometric amount into said internal channel and   an injection of air into said external annular channel, producing at the an outlet of said internal channel, after ignition of said mixture at the outlet of the internal channel, a first flame front resulting from rich combustion, external to said internal channel and attached to a lip at the outlet of the internal channel,   said first flame front being surrounded by a second flame front resulting from lean combustion with the air exiting said external channel.   
     
     
         2 . The injection method according to  claim 1 , wherein said gaseous hydrogen air mixture has a hydrogen richness level that is greater than 2. 
     
     
         3 . The injection method according to  claim 1 , wherein said gaseous hydrogen/air mixture has a hydrogen richness level that is greater than or equal to 4. 
     
     
         4 . The injection method according to  claim 1 , wherein an air flow rate in the external annular channel is chosen such that an overall richness level at the outlet of the injection device is set between 0.15 and 0.5 depending on the operating points of the turbine engine. 
     
     
         5 . The injection method according to  claim 1 , wherein the injection of the gaseous hydrogen/air mixture and the device are configured to create, at the outlet of the internal channel, said first flame front resulting from a rich combustion of said mixture, and to attach it to a lip of the internal channel after ignition of said mixture. 
     
     
         6 . The injection method according to  claim 5 , wherein the gaseous-hydrogen richness of the mixture is chosen so that said rich combustion is carried out with a flame front temperature of less than 1800 K. 
     
     
         7 . The injection method according to  claim 5 , wherein the gaseous-hydrogen richness of the mixture is chosen so that the first flame front is laminar and has a Lewis number greater than  1 , limiting diffusive-thermal instabilities. 
     
     
         8 . The injection method according to  claim 5 , wherein the mixture burned in the first flame front generates residual gases burned in the second flame front which is stabilized by the supply of air from the external annular channel. 
     
     
         9 . The injection method according to  claim 8 , wherein the second flame front is maintained at a temperature below 1800 K. 
     
     
         10 . The injection method according to  claim 8 , wherein the air injected by the annular channel is rotated by an annular swirler.