Gas turbine engine exhaust ejector nozzle with de-swirl cascade

Abstract

The exhaust ejector nozzle has a tubular wall defining an exhaust flow passage leading to an outlet plane, and a de-swirl cascade including a plurality of circumferentially interspaced fins each having a first end connected to the wall adjacent the outlet plane and a second end extending into the exhaust flow passage. The de-swirl cascade can maintain the pumping action of the ejector in high swirl exhaust conditions.

What is claimed is: 
     
         1 . An exhaust ejector nozzle for a gas turbine engine, the exhaust ejector nozzle comprising a tubular wall having a radially inner surface delimiting an exhaust flow passage leading, along an exhaust flow direction, to an outlet plane of the exhaust ejector nozzle, the outlet plane being circumscribed by a downstream edge of the radially inner surface relative the exhaust flow direction, the radially inner surface of the tubular wall defining a central axis, the central axis and the radially inner surface being associated with an exhaust flow orientation; and a de-swirl cascade including a plurality of circumferentially interspaced fins each having a first end connected to the radially-inner surface of the tubular wall adjacent the downstream edge and associated outlet plane, a second end extending into the exhaust flow passage along a given span, and a chord oriented normal to the span. 
     
     
         2 . The ejector nozzle of  claim 1  wherein the span of the fins extends only partially into the exhaust flow passage. 
     
     
         3 . The ejector nozzle of  claim 2  wherein the span extends less than halfway into the primary flow area. 
     
     
         4 . The ejector nozzle of  claim 2  wherein the span extends along an inner peripheral region of the exhaust flow passage. 
     
     
         5 . The ejector nozzle of  claim 1  wherein the chord is inclined by a stagger angle relative to the central axis. 
     
     
         6 . The ejector nozzle of  claim 1  wherein the span, the chord, the stagger angle, and an interspacing between the fins are selected to sustain a pumping action of the ejector in high swirl conditions. 
     
     
         7 . The ejector nozzle of  claim 1  wherein the fins extend normal to the radially-inner surface. 
     
     
         8 . The ejector nozzle of  claim 1  wherein the second end of the fins is a free end. 
     
     
         9 . The ejector nozzle of  claim 1  wherein the fins are immediately adjacent the outlet plane. 
     
     
         10 . The ejector nozzle of  claim 1  wherein the fins are spaced from the downstream edge by a spacing distance which is small relative to the span and the chord. 
     
     
         11 . The ejector nozzle of  claim 1  wherein the span and the chord are of the same order of magnitude. 
     
     
         12 . The ejector nozzle of  claim 1  wherein the tubular wall is cambered and the central axis is correspondingly curved. 
     
     
         13 . A gas turbine engine comprising an ejector having a nozzle and a cowl at an exhaust region, the nozzle extending from a turbine exhaust case of the gas turbine engine, the ejector nozzle having a tubular wall defining an exhaust flow passage leading to an outlet plane, and a de-swirl cascade including a plurality of circumferentially interspaced fins each having a first end connected to the wall adjacent the outlet plane and a second end extending into the exhaust flow passage. 
     
     
         14 . The ejector nozzle of  claim 13  wherein the fins extend partially into a primary flow area of the exhaust flow passage. 
     
     
         15 . The ejector nozzle of  claim 14  wherein the fins extend less than halfway into the primary flow area. 
     
     
         16 . The ejector nozzle of  claim 13  wherein the fins are oriented in an axial orientation relative the tubular wall. 
     
     
         17 . The ejector nozzle of  claim 13  wherein the free end of the fins extends normal to the wall. 
     
     
         18 . The ejector nozzle of  claim 13  wherein the fins are immediately adjacent the outlet plane. 
     
     
         19 . The ejector nozzle of  claim 13  wherein the fins have a span, chord, stagger angle, and interspacing selected to sustain a pumping action of the ejector in high swirl conditions. 
     
     
         20 . A method of de-swirling an external portion of an exhaust gas flow in an ejector nozzle of a gas turbine engine prior to mixing with a secondary flow in an ejector action, the method including
 exposing at least the external portion of the exhaust flow inside the ejector nozzle to a de-swirl cascade including a plurality of circumferentially interspaced fins;   the exhaust flow reaching an outlet plane of the ejector nozzle subsequently to said exposing.