High-turning diffuser strut with flow cross-over slots

Abstract

A turning strut for use in a diffuser of a turbine engine has a leading edge with first and second opposing surfaces depending therefrom that terminate at a trailing edge. Slots extend through the turning strut and reduce in volume from the first surface to the second surface. During turn down operation of the turbine engine, exhaust flow impacts the leading edge at a deviated swirl angle. This results in exhaust flow at the first surface being at a higher pressure than at the second surface, which causes exhaust flow to be induced through the slots. The reduction in slot volume causes exhaust flow through the slots to accelerate. This exhaust flow from the slots is combined with exhaust flow at the second surface. Thusly, momentum of exhaust flow at the second surface is increased to maintain the second laminar boundary layer at the second surface.

1 . A turning strut for use in a diffuser of a turbine engine, the turning strut comprising:
 a curved leading edge;   a first tapered surface depending at one end thereof from the curved leading edge;   a second tapered surface depending at one end thereof from the curved leading edge, the second tapered surface being disposed opposite the first tapered surface;   a trailing edge defined at an other ends of the first and second tapered surfaces; and   at least one slot extending through the turning strut from the first tapered surface to the second tapered surface, the at least one slot reducing in volume from the first tapered surface to the second tapered surface, the at least one slot being disposed proximate the curved leading edge.   
     
     
         2 . The turning strut of  claim 1  wherein the at least one slot comprises a plurality of slots that are aligned. 
     
     
         3 . The turning strut of  claim 1  wherein the at least one slot has a generally rectangular shape with rounded ends. 
     
     
         4 . The turning strut of  claim 1  wherein the at least one slot has a generally compound curve shape. 
     
     
         5 . The turning strut of  claim 4  wherein the generally compound curve shape comprises a serpentine shape. 
     
     
         6 . The turning strut of  claim 1  wherein the at least one slot is disposed proximate the curved leading edge so as to maintain a laminar boundary layer at the second tapered surface during turn down operation of the turbine engine. 
     
     
         7 . A method of turning a flow in a diffuser of a turbine engine, the method comprising:
 impacting the flow at a leading edge of the turning strut, at a swirl angle that is deviated from a design point swirl angle;   defining a first laminar boundary layer at a first tapered surface of the turning strut from the flow thereat, the first tapered surface depending at one end thereof from the leading edge;   defining a second laminar boundary layer at a second surface of the turning strut from the flow thereat, the second tapered surface depending at one end thereof from the leading edge, the second surface being disposed opposite the first surface, wherein the deviated swirl angle results a pressure differential between the flow at the first and second surfaces, wherein the flow at the first surface is at a higher pressure than the exhaust flow at the second surface;   inducing the flow through at least one slot that extends through the turning strut from the first surface to the second surface, the flow through the at least one slot is from the first surface to the second surface and is a result of the pressure differential between the flow at the first and second surfaces;   accelerating the flow through the at least one slot by a reduction of volume of the at least one slot from the first surface to the second surface; and   combining the flow from the at least one slot with the flow at the second surface, wherein momentum of the flow at the second surface is increased to maintain the second laminar boundary layer at the second surface.   
     
     
         8 . The method of  claim 7  further comprising:
 turning down the turbine engine, wherein the swirl angle of the flow deviates from the design point swirl angle. 
 
     
     
         9 . The method of  claim 7  wherein the at least one slot comprises a plurality of slots that are aligned. 
     
     
         10 . The method of  claim 7  wherein the at least one slot has a generally rectangular shape with rounded ends. 
     
     
         11 . The method of  claim 7  wherein the at least one slot has a generally compound curve shape. 
     
     
         12 . The method of  claim 11  wherein the generally compound curve shape comprises a serpentine shape. 
     
     
         13 . The method of  claim 7  wherein the first and second surfaces terminate at a trailing edge. 
     
     
         14 . A turning strut for use in a diffuser of a turbine engine, the turning strut having a generally elongated tear drop shape defined by a leading edge having first and second surfaces depending therefrom, the second surface being disposed opposite the first surface, the first and second surfaces terminating at a trailing edge, at least one slot extending through the turning strut from the first surface to the second surface, the at least one slot reducing in volume from the first surface to the second surface, the at least one slot being disposed proximate the leading edge. 
     
     
         15 . The turning strut of  claim 14  wherein the at least one slot comprises a plurality of slots that are aligned. 
     
     
         16 . The turning strut of  claim 14  wherein the at least one slot has a generally rectangular shape with rounded ends. 
     
     
         17 . The turning strut of  claim 14  wherein the at least one slot has a generally compound curve shape. 
     
     
         18 . The turning strut of  claim 17  wherein the generally compound curve shape comprises a serpentine shape. 
     
     
         19 . The turning strut of  claim 14  wherein the at least one slot is disposed proximate the curved leading edge so as to maintain a laminar boundary layer at the second tapered surface during turn down operation of the turbine engine.