Method of diffusing a gas turbine compression stage, and diffusion stage for implementing same

Abstract

A diffusion stage of a radial or mixed gas turbine engine compressor includes an impeller formed by two plates, between which fluid flows in a centrifugal or inclined manner from a center towards a periphery. Blades of a cascade are distributed between the plates to channel the flow of the fluid between leading edges of the blades at the center and trailing edges at the periphery. At least one of the plates has an internal face including at least one zone with alternating hollow and bump curvatures between two adjacent blades, in at least one of two substantially perpendicular directions, in the direction of flow along the blades and in an inter-blade tangential direction.

1 .- 9 . (canceled) 
     
     
         10 . A method of diffusing a flow of air in a compression stage of a gas turbine engine including a diffusion assembly including an impeller formed by two plates, the method comprising:
 fluid flowing between the two plates in a centrifugal or inclined manner from a center towards a periphery, blades of a cascade being distributed around the impeller between the plates to channel the flow of the fluid between leading edges of the blades at the center and trailing edges at the periphery,   wherein at least one of the plates includes at least one alternation of concave and convex curvatures in a direction of flow along the blades.   
     
     
         11 . A method for diffusing flow of air according to  claim 10 , wherein at least one of the plates also includes at least one alternation of concave and convex curvatures in an inter-blade tangential direction that is substantially perpendicular to the direction of flow along the blades. 
     
     
         12 . A diffusion stage of a radial or mixed gas turbine engine compressor capable of implementing the method according to  claim 10 , comprising:
 an impeller formed by two plates, between which the fluid flows in a centrifugal or inclined manner from a center towards a periphery,   blades of a cascade being distributed around the impeller between the plates to channel the flow of the fluid between leading edges of the blades at the center and trailing edges at the periphery,   wherein at least one of the plates includes an internal face including at least one zone with alternating hollow and bump curvatures between two adjacent blades.   
     
     
         13 . A diffusion stage according to  claim 12 , wherein at least one of the plates includes an internal face further including at least one zone with alternating hollow and bump curvatures between two adjacent blades in an inter-blade tangential direction. 
     
     
         14 . A diffusion stage according to  claim 12 , further comprising alternating hollow and bump zones between the blades, up to substantially 80%, or up to substantially 50%, of a chord line of a blade. 
     
     
         15 . A diffusion stage according to  claim 13 , further comprising hollow and bump zones at the leading edge of the blades, starting upstream of the leading edge. 
     
     
         16 . A diffusion stage according to  claim 13 , comprising hollow and bump zones at the trailing edge of the blades, continuing to downstream of the trailing edge. 
     
     
         17 . A diffusion stage according to  claim 13 , wherein the alternating hollow and bump zones are applied to one and/or the other of the two plates for centrifugal and mixed diffusion. 
     
     
         18 . A diffusion stage according to  claim 17 , wherein the alternating zones, are applied to the plates in a symmetrical manner, relative to a central plane of symmetry of the plates, or in a parallel manner.