Diffuser pipe exit flare

Abstract

A diffuser pipe has a tubular body defining a pipe center axis extending therethrough. The tubular body includes a first portion extending in a generally radial direction from an inlet of the tubular body, a second portion extending in a generally axial direction and terminating at a pipe outlet, and a bend portion fluidly linking the first portion and the second portion. The tubular body has a length defined between the inlet and the pipe outlet. The tubular body has cross-sectional profiles defined in a plane normal to the pipe center axis. An area of the cross-sectional profile at the pipe outlet is at least 20% greater than an area of the cross-sectional profile at a point upstream from the pipe outlet a distance corresponding to 10% of the length of the tubular body.

1 . A compressor diffuser for a gas turbine engine, the compressor diffuser comprising: diffuser pipes having a tubular body defining a pipe center axis extending therethrough, the tubular body including a first portion extending in a generally radial direction from an inlet of the tubular body, a second portion extending in a generally axial direction and terminating at a pipe outlet, and a bend portion fluidly linking the first portion and the second portion, the tubular body having a length defined between the inlet and the pipe outlet, the tubular body having cross-sectional profiles defined in a plane normal to the pipe center axis, an area of the cross-sectional profile at the pipe outlet is at least 20% greater than an area of the cross-sectional profile at a point upstream from the pipe outlet a distance corresponding to 10% of the length of the tubular body. 
     
     
         2 . The compressor diffuser of  claim 1 , wherein the area of the cross-sectional profile at the pipe outlet is at least 25% greater than the area of the cross-sectional profile at the last 10% of the length of the tubular body. 
     
     
         3 . The compressor diffuser of  claim 2 , wherein the area of the cross-sectional profile at the pipe outlet is 50% greater than the area of the cross-sectional profile at the last 10% of the length of the tubular body. 
     
     
         4 . The compressor diffuser of  claim 1 , wherein the area of the cross-sectional profile at the pipe outlet is at least 40% greater than the area of the cross-sectional profile at the last 20% of the length of the tubular body. 
     
     
         5 . The compressor diffuser of  claim 4 , wherein the area of the cross-sectional profile at the pipe outlet is at least 50% greater than the area of the cross-sectional profile at the last 20% of the length of the tubular body. 
     
     
         6 . The compressor diffuser of  claim 5 , wherein the area of the cross-sectional profile at the pipe outlet is 60% greater than the area of the cross-sectional profile at the last 20% of the length of the tubular body. 
     
     
         7 . The compressor diffuser of  claim 1 , wherein the area of the cross-sectional profile at the pipe outlet is at least 50% greater than the area of the cross-sectional profile at the last 30% of the length of the tubular body. 
     
     
         8 . The compressor diffuser of  claim 7 , wherein the area of the cross-sectional profile at the pipe outlet is 66% greater than the area of the cross-sectional profile at the last 30% of the length of the tubular body. 
     
     
         9 . The compressor diffuser of  claim 1 , wherein the cross-sectional profiles increase linearly in area over an upstream segment of the tubular body starting at 0% of the length of the tubular body and terminating at 80% of the length of the tubular body. 
     
     
         10 . A diffuser pipe comprising a tubular body defining a pipe center axis extending therethrough, the tubular body including a first portion extending in a generally radial direction from an inlet of the tubular body, a second portion extending in a generally axial direction and terminating at a pipe outlet, and a bend portion fluidly linking the first portion and the second portion, the tubular body having a length defined between the inlet and the pipe outlet, the tubular body having cross-sectional profiles defined in a plane normal to the pipe center axis, an area of the cross-sectional profile at the pipe outlet is at least 20% greater than the area of the cross-sectional profile at a last 10% of the length of the tubular body. 
     
     
         11 . The diffuser pipe of  claim 10 , wherein the area of the cross-sectional profile at the pipe outlet is at least 25% greater than the area of the cross-sectional profile at the last 10% of the length of the tubular body. 
     
     
         12 . The diffuser pipe of  claim 11 , wherein the area of the cross-sectional profile at the pipe outlet is 50% greater than the area of the cross-sectional profile at the last 10% of the length of the tubular body. 
     
     
         13 . The diffuser pipe of  claim 11 , wherein the area of the cross-sectional profile at the pipe outlet is at least 40% greater than the area of the cross-sectional profile at the last 20% of the length of the tubular body. 
     
     
         14 . The diffuser pipe of  claim 13 , wherein the area of the cross-sectional profile at the pipe outlet is at least 50% greater than the area of the cross-sectional profile at the last 20% of the length of the tubular body. 
     
     
         15 . The diffuser pipe of  claim 14 , wherein the area of the cross-sectional profile at the pipe outlet is 60% greater than the area of the cross-sectional profile at the last 20% of the length of the tubular body. 
     
     
         16 . The diffuser pipe of  claim 10 , wherein the area of the cross-sectional profile at the pipe outlet is at least 50% greater than the area of the cross-sectional profile at the last 30% of the length of the tubular body. 
     
     
         17 . The diffuser pipe of  claim 16 , wherein the area of the cross-sectional profile at the pipe outlet is 66% greater than the area of the cross-sectional profile at the last 30% of the length of the tubular body. 
     
     
         18 . The diffuser pipe of  claim 10 , wherein the cross-sectional profiles increase linearly in area over an upstream segment of the tubular body starting at 0% of the length of the tubular body and terminating at 80% of the length of the tubular body. 
     
     
         19 . A method of increasing a static pressure of fluid exiting a centrifugal compressor of a gas turbine engine, the method including: conveying the fluid through a diffuser pipe to rapidly diffuse the fluid through a last 10% of a length of the diffuser pipe over which a cross-sectional area of the diffuser pipe increases by at least 20%. 
     
     
         20 . The method of  claim 19 , comprising gradually diffusing the fluid over a segment of the diffuser pipe upstream of a last 20% of the length, a cross-sectional area of the segment increasing linearly over its length.