AIRFOIL WITH NONLINEAR COOLING PASSAGE
An example method of manufacturing an airfoil includes providing a ceramic core corresponding to an interior cooling channel. A refractory metal core is provided that corresponds to a cooling passage. The cores are arranged in a mold. An airfoil structure is cast about the cores to provide a turbine engine airfoil. The turbine engine airfoil includes a wall providing the interior cooling channel and an exterior airfoil surface. The cooling passage is provided in the wall and fluidly connects the interior cooling channel to the exterior airfoil surface. The cooling passage includes multiple inlets and multiple outlets respectively adjoining the interior cooling channel and the exterior airfoil surface. At least one of a first inlet and outlet has a different structural flow characteristic than at least one of a second inlet and outlet.
This disclosure relates to a cooling passage for an airfoil.
Turbine blades are utilized in gas turbine engines. As known, a turbine blade typically includes a platform having a root on one side and an airfoil extending from the platform opposite the root. The root is secured to a turbine rotor. Cooling circuits are formed within the airfoil to circulate cooling fluid, such as compressor bleed air. Typically, multiple relatively large cooling channels extend radially from the root toward a tip of the airfoil. Air flows through the channels and cools the airfoil, which is relatively hot during operation of the gas turbine engine.
Some advanced cooling designs use one or more radial cooling passages arranged between the cooling channels and an airfoil exterior surface that extend from the root toward the tip. The cooling passages provide high convective cooling.
Other current airfoil tooling designs make use of some cooling holes drilled through airfoil walls and into internal cooling passages. In this type of configuration, the geometry of the holes is limited to a straight hole with the possibility for some flow diffusing feature added near the exit of the hole. As holes must be drilled in a straight line, minimal angles with the airfoil exterior surface must be observed. The length of holes is dictated by manufacturing constraints.
SUMMARYAn example method of manufacturing an airfoil includes providing a ceramic core corresponding to an interior cooling channel. A refractory metal core is provided that corresponds to a cooling passage. The cores are arranged in a mold. An airfoil structure is cast about the cores to provide a turbine engine airfoil.
The turbine engine airfoil includes a wall providing the interior cooling channel and an exterior airfoil surface. The cooling passage is provided in the wall and fluidly connects the interior cooling channel to the exterior airfoil surface. The cooling passage includes multiple inlets and multiple outlets respectively adjoining the interior cooling channel and the exterior airfoil surface. At least one of a first inlet and outlet has a different structural flow characteristic than at least one of a second inlet and outlet.
These and other features of the disclosure can be best understood from the following specification and drawings, the following of which is a brief description.
A gas turbine engine (GTE) 10 is illustrated schematically in
The turbine section 22 includes turbine blades 24 rotatable about the axis A and arranged in a circumferential direction C, shown in
Referring to
In the example, a cooling passage 46 fluidly interconnects the interior cooling channel 42 to the exterior airfoil surface 34 and is arranged on the pressure side of the turbine blade 24. The cooling passage 46 includes multiple inlets 48 adjoining a radially extending intermediate passage 50. Multiple outlets 52 adjoin the intermediate passage 50, which enables the pressure to be better equalized across the outlets 52. The inlets 48 each provide an entrance 54 at the interior cooling channel 42. The extended intermediate passage 50 provide exits 56 arranged at the end of the airfoil structure near the tip 32. The cooling passage 46 has a generally S-shaped cross-section. The flow path from the entrance 54 to the exit 56 can replace the straight, drilled holes previously used. Trip strips 58, schematically shown in
In the example, the interior cooling channel 42 and cooling passage 46 are provided by one or more ceramic cores arranged within a mold. Referring to
The RMC 66 is formed to provide a desired core shape. Typically, the RMC can be stamped out of a flat sheet metal. Subsequently, this stamped RMC shape is bent to a desired shape to provide a correspondingly shaped cooling passage 46, an example of which is illustrated in
The RMC 66 can be configured provide different structural flow characteristics with any desired geometry to produce holes of any desired length, path and exit shape, for example. For example, by utilizing different cross-sectional areas along the length of the RMC 66 (for example in along the flow path from the entrance 54 to the exit 56), each hole may be designed to provide desired pressure drop control across the radial length of the cooling passage 46 rather than over pressurizing many of the drilled holes with only a few holes optimized. The cooling passage 46 may include any heat transfer augmentation features such as trip strips to improve heat transfer characteristics and control pressure drops through the holes. Diffuser features 90 may also be provided in the cooling passage 46 and in the exits 56 (see, e.g.,
Although example embodiments have been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of the claims. As another example, the method disclosed above can be applied to manufacturing blade outer air seals (BOAS). For that reason, the following claims should be studied to determine their true scope and content.
Claims
1. A turbine engine airfoil comprising:
- an airfoil structure having a wall providing an interior cooling channel and an exterior airfoil surface, a cooling passage provided in the wall fluidly connecting the interior cooling channel to the exterior airfoil surface, the cooling passage including at least one inlet and multiple outlets respectively adjoining the interior cooling channel and the exterior airfoil surface, at least one of a first inlet and outlet having a different structural flow characteristic than at least one of a second inlet and outlet.
2. The turbine engine airfoil according to claim 1, wherein the structural flow characteristic includes at least one of length, path and shape.
3. The turbine engine airfoil according to claim 2, wherein the shape includes a cross-sectional area, the first outlet having a different cross-sectional area than the second outlet.
4. The turbine engine airfoil according to claim 1, wherein the cooling passage extends generally axially within the wall, and including a generally axially extending intermediate passage fluidly connecting the inlets to the outlets.
5. The turbine engine airfoil according to claim 4, wherein multiple inlets each include an entrance at the interior cooling channel, and the outlets each include an exit at the exterior airfoil surface, the entrances having a greater cross-sectional area than that of the exits.
6. The turbine engine airfoil according to claim 5, wherein a first entrance includes an area that is greater than a second entrance.
7. The turbine engine airfoil according to claim 5, wherein a first exit has an area that is greater than a second exit.
8. The turbine engine airfoil according to claim 1, wherein the cooling passage includes trip strips.
9. The turbine engine airfoil according to claim 1, wherein the cooling passage is nonlinear.
10. A method of manufacturing the airfoil of claim 1, comprising the steps of:
- providing a ceramic core corresponding to an interior cooling channel;
- providing a refractory metal core corresponding to a cooling passage;
- arranging the cores in a mold; and
- casting an airfoil structure around the cores, wherein the airfoil structure includes a wall separating the interior cooling channel from an exterior airfoil surface, the cooling passage provided in the wall fluidly connects the interior cooling channel to the exterior airfoil surface, the cooling passage including at least one inlet and multiple outlets respectively adjoining the interior cooling channel and the exterior airfoil surface, at least one of a first inlet and outlet having a different structural flow characteristic than at least one of a second inlet and outlet.
11. The method according to claim 10, wherein the refractory metal core providing step includes forming a desired core shape and bending the formed desired core shape to correspond to the cooling passage.
12. The method according to claim 11, wherein the refractory metal core providing step includes providing notches in the cooling passage corresponding to trip strips.
13. The method according to claim 11, wherein the bending step includes the bending the cooling passage into generally an S-shape in a lateral direction.
14. The method according to claim 10, wherein the arranging step includes locating the refractory metal core relative to the ceramic core.
15. The method according to claim 10, wherein the casting step includes forming a diffuser feature in the cooling passage.
Type: Application
Filed: Aug 31, 2011
Publication Date: Feb 28, 2013
Inventors: William Abdel-Messeh (Middletown, CT), Justin D. Piggush (LaCrosse, WI)
Application Number: 13/222,490
International Classification: F01D 5/18 (20060101); B22C 9/10 (20060101); B22D 25/02 (20060101);