Patent Application
20130243591
This disclosure relates to a gas turbine engine, and more particularly to an airfoil cooling circuit that includes at least one trip strip to cool an airfoil of a gas turbine engine.
Gas turbine engines typically include a compressor section, a combustor section and a turbine section. In general, during operation, air is pressurized in the compressor section and mixed with fuel and burned in the combustor section to generate hot combustion gases. The hot combustion gases flow through the turbine section which extracts energy from the hot combustion gases to power the compressor section and other gas turbine engine loads.
The compressor and turbine sections of the gas turbine engine typically include alternating rows of rotating blades and stationary vanes. The rotating blades extract the energy from the hot combustion gases that are communicated through the gas turbine engine, and the vanes convert the velocity of the airflow into pressure and prepare the airflow for the next set of blades. The hot combustion gases are communicated over airfoils of the blades and vanes. The airfoils can include cooling circuits that receive cooling airflow for cooling the airfoils during engine operation.
An airfoil for a gas turbine engine according to one exemplary embodiment includes an airfoil body that extends between a leading edge and a trailing edge. A cooling circuit can be defined within the airfoil body. The cooling circuit can include at least one trip strip disposed within a cavity of the cooling circuit between a leading edge inner wall and a first rib. The at least one trip strip can include an increasing height in a direction from the first rib toward the leading edge inner wall.
In a further embodiment of the foregoing airfoil embodiment, the airfoil can be a blade.
In a further embodiment of either of the foregoing airfoil embodiments, the airfoil can be a vane.
In a further embodiment of any of the foregoing airfoil embodiments, the cavity can extend between a suction side inner wall and a pressure side inner wall.
In a further embodiment of any of the foregoing airfoil embodiments, the increasing height can extend in a direction from one of the suction side inner wall and the pressure side inner wall toward the other of the suction side inner wall and the pressure side inner wall.
In a further embodiment of any of the foregoing airfoil embodiments, at least one trip strip can include a leading edge portion adjacent the leading edge inner wall and a trailing edge portion adjacent to the first rib.
In a further embodiment of any of the foregoing airfoil embodiments, the leading edge portion can be generally perpendicular to the leading edge inner wall.
In a further embodiment of any of the foregoing airfoil embodiments, a gap can extend between the leading edge portion and the leading edge inner wall.
In a further embodiment of any of the foregoing airfoil embodiments, the at least one trip strip can be hockey stick shaped.
In a further embodiment of any of the foregoing airfoil embodiments, the at least one trip strip can include at least two trip strips that are arranged in a V-shaped chevron configuration.
In a further embodiment of any of the foregoing airfoil embodiments, the at least two trip strips are staggered along the cavity of the cooling circuit.
In a further embodiment of any of the foregoing airfoil embodiments, the at least on trip strip can include at least a first trip strip and a second trip strip having a different configuration from the first trip strip.
In a further embodiment of any of the foregoing airfoil embodiments, the first trip strip and the second trip strip can be non-symmetrically arranged relative to a mean camber line of the cavity of the cooling circuit.
A gas turbine engine according to another exemplary embodiment includes a compressor section, a combustor section in fluid communication with said compressor section, a turbine section in fluid communication said combustor section, an airfoil disposed in at least one of the compressor section and the turbine section. The airfoil can include an airfoil body that extends between a leading edge and a trailing edge. A cooling circuit can be disposed within the airfoil body and have a cavity adjacent to the leading edge. The cavity can include a leading edge inner wall, a suction side inner wall and a pressure side inner wall. A trip strip can include a leading edge portion that extends a first distance from at least one of the suction side inner wall and the pressure side inner wall and a trailing edge portion can extend a second distance from at least one of the suction side inner wall and the pressure side inner wall. The first distance can be greater than said second distance.
In a further embodiment of the foregoing gas turbine engine embodiment, the leading edge portion can be adjacent to the leading edge inner wall and the trailing edge portion can be adjacent to a rib of the cavity.
In a further embodiment of either of the foregoing gas turbine engine embodiments, the leading edge portion can be generally perpendicular to the leading edge inner wall.
In a further embodiment of any of the foregoing gas turbine engine embodiments, the gas turbine engine is a land based gas turbine engine.
In a further embodiment of any of the foregoing gas turbine engine embodiments, the gas turbine engine is a turbofan gas turbine engine.
A method for cooling an airfoil of a gas turbine engine according to yet another exemplary embodiment includes communicating a cooling airflow through a cavity of a cooling circuit of the airfoil, and directing a first portion of the cooling airflow axially along an upstream face of at least one trip strip of the cooling circuit toward a leading edge of the airfoil to cool the leading edge of the airfoil.
In a further embodiment of the foregoing method embodiment, a gap can be provided between a leading edge inner wall of the airfoil and a leading edge portion of the at least one trip strip.
In a further embodiment of either of the foregoing method embodiments, a second portion of the cooling airflow can be directed across a height of the at least one trip strip.
The various features and advantages of this disclosure will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows.
This view is highly schematic and is included only to provide a basic understanding of a gas turbine engine and not to limit the disclosure. This disclosure extends to all types of gas turbine engines and to all types of applications, including but not limited to, multiple spool turbofan engines that can incorporate a fan section. This disclosure could also extend to flight engines, auxiliary power units, or power generation units.
The compressor section 12 and the turbine section 16 can each include alternating rows of rotor assemblies and vane assemblies (not shown). The rotor assemblies carry a plurality of rotating blades, while each vane assembly includes a plurality of vanes. The blades of the rotor assemblies create or extract energy (in the form of pressure) from core airflow that is communicated through the gas turbine engine 10. The vanes of the vane assemblies direct airflow to the blades of the rotor assemblies to either add or extract energy.
Various components of the gas turbine engine 10, including airfoils such as the blades and vanes of the compressor section 12 and the turbine section 16, may be subjected to repetitive thermal cycling under widely ranging temperatures and pressures. The hardware of the turbine section 16 is particularly subjected to relatively extreme operating conditions. Therefore, some components may require internal cooling circuits for cooling the parts during engine operation. Example cooling circuits that include features such as trip strips for cooling these components are discussed below.
The airfoil 40 includes an airfoil body 42 that extends between an inner platform 44 (on an inner diameter side) and an outer platform 46 (on an outer diameter side). The airfoil 40 also includes a leading edge 48, a trailing edge 50, a pressure side 52 and a suction side 54. The airfoil body 42 extends in chord between the leading edge 48 and the trailing edge 50.
Both the inner platform 44 and the outer platform 46 include leading and trailing edge rails 56 having one or more engagement features 57 for mounting the airfoil 40 to the gas turbine engine 10, such as to an engine casing. Other engagement feature configurations are contemplated as within the scope of this disclosure, including but not limited to, hooks, rails, bolts, rivets and tabs that can be incorporated into the airfoil 40 to retain the airfoil 40 to the gas turbine engine 10.
A gas path 58 is communicated axially downstream through the gas turbine engine 10 in a direction that extends from the leading edge 48 toward the trailing edge 50 of the airfoil body 42. The gas path 58 (for the communication of core airflow along a core flow path) extends between an inner gas path 60 associated with the inner platform 44 and an outer gas path 62 associated with the outer platform 46 of the airfoil 40. The inner platform 44 and the outer platform 46 are connected to the airfoil 40 at the inner and outer gas paths 60, 62 via fillets 64.
The airfoil body 42 includes an internal circuit 66 having an inlet 68 that receives a cooling airflow 70 from an airflow source 75 that is external to the airfoil 40. In this embodiment, the inlet 68 of the internal circuit 66 is positioned at the outer platform 46 of the airfoil 40, although the inlet 68 could also be positioned at the inner platform 44. The cooling airflow 70 is a lower temperature than the airflow of the gas path 58 that is communicated across the airfoil body 42. In one example, the cooling airflow 70 is a bleed airflow that can be sourced from the compressor section 12 or any other portion of the gas turbine engine 10 that is upstream from the airfoil 40. The cooling airflow 70 is circulated through a cooling circuit 72 (See
A cooling circuit such as disclosed herein can be disposed in any component that requires cooling, including but not limited to those components that are exposed to the gas path 58 of the gas turbine engine 10. In the illustrated embodiments and for the purpose of providing detailed examples, the cooling circuits of this disclosure are disposed within a portion of an airfoil, such as a stator vane or a rotor blade. It should be understood, however, that the cooling circuits are not limited to these applications and could be utilized within other areas of the gas turbine engine that are exposed to relatively extreme environments, including but not limited to blade outer air seals (BOAS) and platforms.
The example cooling circuit 72 includes a first cavity 74 (i.e., a leading edge cavity), a second cavity 76 (i.e., an intermediate cavity), and a third cavity 78 (i.e., a trailing edge cavity). The cavities 74, 76, 78 direct the cooling airflow 70 through the cooling circuit 72 to cool any high temperature areas of the airfoil body 42. The first cavity 74 is in fluid communication with the second cavity 76, and the second cavity 76 is in fluid communication with the third cavity 78. Accordingly, the cooling airflow 70 received within the cooling circuit 72 can be circulated through the first cavity 74, then through the second cavity 76, and then through the third cavity 78 to cool the airfoil 40. Also, the cooling airflow 70 could be communicated in the opposite direction (in a direction from the inner platform 44 toward the outer platform 46) within the scope of this disclosure.
A first rib 81 separates the first cavity 74 from the second cavity 76, and a second rib 83 divides the second cavity 76 from the third cavity 78. The first and second ribs 81, 83 extend generally parallel to a longitudinal axis of the airfoil 40.
The internal circuit 66 of the airfoil 40 establishes a leading edge inner wall 67 and a trailing edge inner wall 69. The cooling circuit 72 extends axially between the leading edge inner wall 67 and the trailing edge inner wall 69.
One or more trip strips 80 can be disposed within the first cavity 74 of the cooling circuit 72 between the first rib 81 and the leading edge inner wall 67. In this example, the trips strips 80 include a hockey stick shape. In other words, a leading edge portion 90 is transverse to a trailing edge portion 92 of the trip strip (See
Referring to
The example trip strip 80 includes a leading edge portion 90 that is adjacent to the leading edge inner wall 67 and a trailing edge portion 92 that is adjacent to the first rib 81 that divides the first cavity 74 from the second cavity 76. The trip strip 80 can extend between the leading edge inner wall 67 and the first rib 81, while a gap 88 can extend between a tip 94 of the leading edge portion 90 and the leading edge inner wall 67 to force cooling airflow 70 to impinge on the leading edge inner wall 67 without obstructing forward flow of the cooling airflow 70.
The trip strip 80 includes an increasing height in a direction from the first rib 81 toward the leading edge inner wall 67. In this example, the leading edge portion 90 extends a first distance H1 from the suction side inner wall 84 (or pressure side inner wall 86) and the trailing edge portion 92 of the trip strip 80 extends a second distance H2 from the suction side inner wall 84 (or pressure side inner wall 86). The first distance H1 is greater than the second distance H2, in one exemplary embodiment.
In this exemplary embodiment, the trailing edge portion 92 is angled relative to the leading edge portion 90. A transition portion 91 can transition the leading edge portion 90 into the trailing edge portion 92. The leading edge portion 90 can be generally perpendicular to the leading edge inner wall 67, and the trailing edge portion 92 can be generally transverse to the first rib 81 and the leading edge inner wall 67.
The trip strip 80 also includes an upstream face 93 and a downstream face 95 opposite from the upstream face 93. The upstream face 93 faces the oncoming cooling airflow 70 as the cooling airflow 70 is communicated through the cooling circuit 72.
For example, a first portion P1 of the cooling airflow 70 can be directed over the height of the trip strips 80, which creates turbulence in the cooling airflow 70. A second portion P2 of the cooling airflow 70 can also be communicated axially along at least a portion of the upstream face 93 of the trip strip 80 to direct the second portion P2 of the cooling airflow 70 toward the leading edge inner wall 67. The trip strips 80 can redirect the momentum of at least a portion of the cooling airflow 70 toward the leading edge inner wall 67, and the increased height H1 (See
The trip strips 280, 282 could also be longitudinally staggered along one or more of the cavities 74, 76, 78 (shown longitudinally staggered in the second cavity 76 of
Although the different examples have specific components shown in the illustrations, embodiments of this disclosure are not limited to those particular combinations. It is possible to use some of the components or features from one of the examples in combination with features or components from another one of the examples.
Furthermore, the foregoing description shall be interpreted as illustrative and not in any limiting sense. A worker of ordinary skill in the art would understand that certain modifications could come within the scope of this disclosure. For these reasons, the following claims should be studied to determine the true scope and content of this disclosure.
