Turbo machine combustion assembly comprising an improved fuel supply circuit

Abstract

Turbo machine combustion assembly ( 1 ) comprising a combustion chamber ( 10 ), at least one starting injector ( 17 ), a plurality of main injectors ( 18 ) distributed at constant angular intervals around the circumference of the combustion chamber, each starting injector being positioned between two consecutive main injectors, equal distances therefrom, and a fuel supply circuit ( 40 ) supplying fuel to the injectors, in which assembly the combustion chamber is delimited by two axisymmetric walls—an external wall ( 14 ) and an internal wall ( 12 )—which are connected by an annular chamber end wall ( 16 ), the fuel supply circuit being designed to supply at least one starting injector continuously, each continuously-supplied starting injector being oriented toward the chamber end wall and dimensioned to spread a spray (F) of fuel between 120° and 180° wide, and the flow rate of fuel injected by the main injectors ( 18′ ) between which the starting injectors are positioned being reduced by comparison with the flow rate injected by the other main injectors ( 18 ).

1 . A turbomachine combustion assembly, comprising:
 a combustion chamber,   at least one starting injector, suitable for initiating combustion in the chamber,   a plurality of main injectors distributed at a constant annular interval around the circumference of the combustion chamber, designed to supply fuel to the combustion chamber when combustion has been initiated, and   a fuel supply circuit for the injectors,   
       wherein the combustion chamber is delimited by two axisymmetric outer and inner walls extending one inside the other and which are connected by an annular chamber end wall, the combustion assembly being characterized in that the fuel supply circuit is designed to supply fuel to at least one starting injector continuously, so that said injector is supplied with fuel both throughout the initiation of the combustion and when fuel is supplied to the chamber when the combustion has been initiated, 
       in that each continuously-supplied starting injector is oriented toward the chamber end wall and is dimensioned to spread a spray (F) of fuel having an angular aperture in a first direction between 120° and 180°, and 
       in that the flow of fuel injected by the main injectors between which the starting injectors are positioned is reduced by comparison with the flow injected by the other main injectors,
 and in that each starting injector is positioned between two consecutive main injectors at equal distance therefrom. 
 
     
     
         2 . The turbomachine combustion assembly according to  claim 1 , wherein the supply circuit is designed to supply all the starting injectors continuously. 
     
     
         3 . The turbomachine combustion assembly according  claim 1 , wherein the ratio of the flow rate divided by the square root of the pressure difference of the fuel mixture between its pressure at the input and at the output of the injector for the main injectors between which each starting injector is positioned is less than said ratio for the other main injectors. 
     
     
         4 . The turbomachine combustion assembly according to  claim 1 , wherein each continuously-supplied starting injector is dimensioned to spread a spray (F) having an angular aperture between 15 and 35° in a second dimension orthogonal to the first direction. 
     
     
         5 . The combustion assembly according to  claim 1 , wherein the combustion chamber is of the type having aerodynamic or aeromechanical injectors. 
     
     
         6 . The combustion assembly according  claim 1 , wherein the chamber is of type comprising pre-evaporation rods, each pre-evaporation rod being shaped so that the fuel injected by the main injectors is directed toward the chamber end wall. 
     
     
         7 . The turbomachine combustion assembly according to  claim 6 , wherein the combustion chamber comprises:
 on its inner wall, a plurality of air intake openings, and   on its outer wall, a plurality of so-called dilution openings,   
       wherein the number and diameter of said openings are designed to distribute the air intake in the combustion chamber and to preserve the homogeneity of the temperature field in said chamber. 
     
     
         8 . The turbomachine combustion assembly according to  claim 7 , wherein the combustion chamber is a reverse-flow chamber. 
     
     
         9 . The turbomachine combustion assembly according to  claim 8 , wherein the fuel supply circuit comprises:
 a supply duct for the starting injectors,   a supply duct for the main injectors, and   a fuel distribution duct, in fluid communication with the supply ducts and designed to supply fuel to said ducts,   
       the supply circuit further comprising a distribution system designed to shut off fluid communication between the fuel distribution duct and the supply duct for the main injectors when the fuel pressure in the distribution duct is less than a predetermined threshold. 
     
     
         10 . The combustion assembly according to  claim 9 , wherein the distribution system is further designed to distribute the fuel flow between main injectors having a reduced flow rate and the other main injectors. 
     
     
         11 . A turbomachine comprising a combustion assembly according to  claim 10 .