This disclosure relates to an impingement cooling device for a gas turbine engine that increases cooling air flow to a transition duct.
Primary components of a gas turbine engine include a compressor section, a combustion section, and a turbine section. As known, air compressed in the compressor section is mixed with fuel and burned in the combustion section to produce hot gases that are expanded in the turbine section.
A combustor is positioned at a compressor discharge opening and is connected to the turbine section by transition ducts. The transition ducts are circumferentially spaced apart from each other in an annular pattern. Each transition duct is spaced from an adjacent transition duct by a small gap. The transition ducts conduct the hot gases from the combustor to a first stage inlet of the turbine section. A cooling impingement sleeve is positioned to surround each of the transition ducts. Each impingement sleeve includes a plurality of air holes that direct cooling air toward the heated transition ducts.
Air from the compressor section exits a diffuser via a discharge casing that surrounds the transition ducts. Some of this air is directed to cool the transition duct via the air holes in the impingement sleeve. The remaining air is eventually mixed with fuel in a combustion chamber.
Due to the tight packaging constraints between the various engine components, it may be difficult to direct a sufficient amount of cooling air to the transition duct. The compressor discharge air passing between the closely spaced transition ducts is accelerated through the gap between adjacent transition ducts, which results in a low local static pressure. This reduces the pressure drop that drives cooling air through the impingement sleeve, which can result in inadequate local cooling.
One proposed solution for increasing cooling air flow has been to weld scoops onto the impingement cooling sleeve. The scoops comprise semi-hemispherical members, i.e. a curved member that forms half of a hemisphere, that are welded to the impingement cooling sleeve at different air hole locations. These scoops have not been efficient in capturing and redirecting flow through impingement cooling holes.
Accordingly, there is a need to provide an impingement sleeve configuration with a more effective cooling structure.
An impingement cooling sleeve includes a sleeve body having an inner surface to face a transition duct and an outer surface facing opposite the inner surface. At least one cooling hole is formed within the sleeve body and is used to direct cooling air toward the transition duct. At least one conduit member is attached to the sleeve body and is associated with the cooling hole.
In one example, the conduit member has a first opening to define an air inlet and a second opening to define an air outlet, with the first opening being spaced apart from the outer surface of the sleeve body by a distance.
In one example, the first opening comprises an annular end face surface that defines a plane that is obliquely orientated relative to an outer surface of the sleeve body.
The conduit members of the invention provide a more effective cooling configuration that is less sensitive to variations in air flow direction.
The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiment. The drawings that accompany the detailed description can be briefly described as follows.
As shown in
An impingement cooling sleeve 50 is positioned to surround each transition duct 30. The impingement cooling sleeve 50 includes a sleeve body 51 having an inner surface 52 that faces the outer surface 32 of the transition duct 30 and an outer surface 54 that faces the discharge casing 40. The inner surface 52 of the impingement cooling sleeve 50 is spaced circumferentially apart from the outer surface 32 of the transition duct 30 to define a chamber 56 around the transition duct 30. The impingement cooling sleeve 50 includes a plurality of cooling holes 58 that extend through a thickness T of the sleeve body of the impingement cooling sleeve 50 from the outer surface 54 to the inner surface 52.
Air flow indicated by arrow passes from the discharge casing 40 into the chamber 56 via the cooling holes 58 to provide cooling air for the transition duct 30.
As shown in
Each impingement cooling sleeve 50 includes a plurality of conduit members 60 to direct an increased portion of the air flow 38 toward the transition duct 30 to provide increased cooling. Each conduit member 60 is associated with one of the cooling holes 58 in the impingement cooling sleeve 50. One conduit member 60 is not necessarily associated with every cooling hole; however, depending upon the application, conduit members could be associated with each cooling hole. In one example, the conduit members 60 are attached to the impingement cooling sleeve 50 in areas where there is low local static pressure. The conduit members 60 can be attached by welding or other attachment methods.
One example of a conduit member 60 is shown in
In the example of
In one example, the first A1 and second A2 axes are perpendicular to each other. It should be understood that an angular relationship between the first A1 and second A2 axes could be varied as needed to provide increased flow.
The first opening 62 comprises an annular end face 78 that defines a plane P that is obliquely orientated relative to the outer surface 54 of the impingement cooling sleeve 50. The orientation of this annular end face 78 makes the conduit 60 less sensitive to variations in directions of air flow relative to the first axis A1. In other words, air that flows in a non-parallel direction relative to the first axis A1 will have a minimal effect on capture efficiency due to the oblique orientation of the first opening 62.
Each cooling hole 58 is defined by a cooling hole diameter H1. Each conduit 60 has an inner circumferential surface 80 defined by an inner diameter H2 and an outer circumferential surface 82 defined by an outer diameter H3. The conduit 60 is attached to the inner surface 52 of the sleeve 50 with a fillet weld W.
In the example shown in
The first tube end 102 defines a first opening 108 for the air inlet and the second tube end 104 defines a second opening 110 for the air outlet. The first opening 108 is spaced apart from the outer surface 54 of the impingement cooling sleeve 50 by a distance D to improve flow capture efficiency as discussed above. The distance D can be varied as needed depending upon the application and packaging constraints.
Similar to the configuration set forth in
In the example shown in
Although a combination of features is shown in the illustrated examples, not all of them need to be combined to realize the benefits of various embodiments of this disclosure. In other words, a system designed according to an embodiment of this disclosure will not necessarily include all of the features shown in any one of the Figures or all of the portions schematically shown in the Figures. Moreover, selected features of one example embodiment may be combined with selected features of other example embodiments.
The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this disclosure. The scope of legal protection given to this disclosure can only be determined by studying the following claims.