Patent Application
20160230567
This disclosure relates to a gas turbine engine airfoil. More particularly, the disclosure relates to a cooling configuration in the airfoil.
Gas turbine engines typically include a compressor section, a combustor section and a turbine section. During operation, air is pressurized in the compressor section and is mixed with fuel and burned in the combustor section to generate hot combustion gases. The hot combustion gases are communicated through the turbine section, which extracts energy from the hot combustion gases to power the compressor section and other gas turbine engine loads.
Both the compressor and turbine sections may include alternating series of rotating blades and stationary vanes that extend into the core flow path of the gas turbine engine. For example, in the turbine section, turbine blades rotate and extract energy from the hot combustion gases that are communicated along the core flow path of the gas turbine engine. The turbine vanes, which generally do not rotate, guide the airflow and prepare it for the next set of blades.
Many turbine blades having turns that provide a serpentine shape, which create undesired pressure losses. Some turbine blades use internally cored serpentine cavities to cool the mid-body section of the airfoil between the leading and trailing edges. The cooling flow is fed into a serpentine passage from the root of the blade. Most serpentine configurations use three to five passageways with the last passageway flowing radially outward from the root and finally terminating near the tip. If cooling air does not reach the tip of the last passage, the airfoil could develop a hot spot and burn through. Having the last passageway flow radially outward takes advantage of pumping action from the circumferential forces on the turbine blade, which ensures cooling air reaches the tip of the last passage.
In one exemplary embodiment, a gas turbine engine airfoil includes a platform, and spaced apart walls that provide an exterior airfoil surface that extends radially from the platform to an end opposite the platform. A serpentine cooling passage is arranged between the walls and has a first passageway that extends from the platform toward the end and a second passageway fluidly connecting to the first passageway and extending from the end toward the platform to an end. A platform cooling passageway is fluidly connected to the end and extends transversely into the platform. A cooling hole fluidly connects the platform cooling passageway to an exterior surface.
In a further embodiment of the above, multiple cooling passages extend radially within the airfoil and are spaced apart from one another in a chord-wise direction.
In a further embodiment of any of the above, the multiple passages include a leading edge passage that is arranged near a leading edge of the exterior airfoil surface.
In a further embodiment of any of the above, the multiple passages include a trailing edge passage that is arranged near a trailing edge of the exterior airfoil surface.
In a further embodiment of any of the above, each of the multiple passages includes discrete inlets that provide cooling flow to the passage.
In a further embodiment of any of the above, the first and second passageways provide an up-pass passageway and a down-pass passageway that form a U-shaped cooling passage.
In a further embodiment of any of the above, the serpentine cooling passage includes a third passageway that is fluidly connected to the second passageway and extends from the platform toward the end.
In a further embodiment of any of the above, the serpentine cooling passage terminates at the end.
In a further embodiment of any of the above, the platform cooling passageway extends along a pressure side of the platform.
In a further embodiment of any of the above, the platform cooling passageway extends along a suction side of the platform.
In a further embodiment of any of the above, the platform cooling passageway extends along a pressure side and a suction side of the platform.
In a further embodiment of any of the above, multiple cooling holes fluidly connect the platform cooling passageway to the exterior surface.
In another exemplary embodiment, a core for a gas turbine engine airfoil includes a serpentine core portion that is configured to provide an inlet that extends to a first passageway. A second passageway is fluidly connected to the first passageway to form a U-shaped cooling passage. A platform core portion is configured to provide a platform cooling passageway that is arranged transverse and connected to the second passageway.
In a further embodiment of the above, the first passageway is an up-pass passageway and the second passageway is a down-pass passageway. The down-pass passageway terminates near the platform cooling passageway.
In a further embodiment of any of the above, the first passageway is an up-pass passageway and the second passageway is a down-pass passageway. The platform cooling passageway is generally normal to the down-pass passageway.
In a further embodiment of any of the above, the platform core portion extends in the opposite directions from the serpentine core portion.
In another exemplary embodiment, a method of cooling an airfoil comprising the steps of supplying a cooling fluid to an airfoil in a radial direction toward an end, turning the cooling fluid from the end back toward the root to a region near a platform, conveying the cooling fluid from the region to the platform and exiting the cooling fluid through a cooling hole to an exterior surface.
In a further embodiment of the above, the supplying step includes providing the cooling fluid through multiple discrete inlets to multiple cooling passages.
In a further embodiment of any of the above, the turning step includes flowing the cooling fluid along a U-shaped serpentine cooling passage.
In a further embodiment of any of the above, the conveying step includes conveying the cooling fluid to the platform on opposite sides of an airfoil.
The disclosure can be further understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
The embodiments, examples and alternatives of the preceding paragraphs, the claims, or the following description and drawings, including any of their various aspects or respective individual features, may be taken independently or in any combination. Features described in connection with one embodiment are applicable to all embodiments, unless such features are incompatible.
The exemplary engine 20 generally includes a low speed spool 30 and a high speed spool 32 mounted for rotation about an engine central longitudinal axis A relative to an engine static structure 36 via several bearing systems 38. It should be understood that various bearing systems 38 at various locations may alternatively or additionally be provided, and the location of bearing systems 38 may be varied as appropriate to the application.
The low speed spool 30 generally includes an inner shaft 40 that interconnects a fan 42, a low pressure compressor 44 and a low pressure turbine 46. The inner shaft 40 is connected to the fan 42 through a speed change mechanism, which in exemplary gas turbine engine 20 is illustrated as a geared architecture 48 to drive the fan 42 at a lower speed than the low speed spool 30. The high speed spool 32 includes an outer shaft 50 that interconnects a high pressure compressor 52 and high pressure turbine 54. A combustor 56 is arranged in exemplary gas turbine 20 between the high pressure compressor 52 and the high pressure turbine 54. A mid-turbine frame 57 of the engine static structure 36 is arranged generally between the high pressure turbine 54 and the low pressure turbine 46. The mid-turbine frame 57 supports one or more bearing systems 38 in the turbine section 28. The inner shaft 40 and the outer shaft 50 are concentric and rotate via bearing systems 38 about the engine central longitudinal axis A, which is collinear with their longitudinal axes.
The core airflow C is compressed by the low pressure compressor 44 then the high pressure compressor 52, mixed and burned with fuel in the combustor 56, then expanded over the high pressure turbine 54 and low pressure turbine 46. The mid-turbine frame 57 includes airfoils 59 which are in the core airflow path. The turbines 46, 54 rotationally drive the respective low speed spool 30 and high speed spool 32 in response to the expansion. It will be appreciated that each of the positions of the fan section 22, compressor section 24, combustor section 26, turbine section 28, and fan drive gear system 48 may be varied. For example, gear system 48 may be located aft of combustor section 26 or even aft of turbine section 28, and fan section 22 may be positioned forward or aft of the location of gear system 48.
The disclosed serpentine cooling passage may be used in various gas turbine engine components. For exemplary purposes, a turbine blade 64 is described. It should be understood that the cooling passage may also be used in vanes, blade outer air seals, and turbine platforms, for example.
Referring to
The airfoil 78 of
The airfoil 78 includes multiple cooling passages 90 provided between the pressure and suction walls 86, 88. The exterior airfoil surface may include multiple film cooling holes (not shown) in fluid communication with the cooling passage 90. Flow through the cooling passage 90 illustrated in
Referring to
The turbine blade 64 includes multiple cooling passages 90A, 90B, 90C. The cooling passage 90A corresponds to a leading edge cooling passage, and the cooling passage 90C corresponds to a trailing edge cooling passage. In one type of cooling configuration, a serpentine cooling passage 90B is provided in the mid-body section of the airfoil 78 between the leading and trailing edge cooling passages 90A, 90C, as shown in
Typically, a serpentine cooling passage 90B has at least one up-pass connected to at least one down-pass interconnected to one another by a bend to provide a U-shaped passage, as shown in
The mid-body of the airfoil 78 may be susceptible to developing a hot spot if the pumping action of the fluid is ineffective. Thus, the disclosed cooling configuration provides a cooling flow exit at a location on the turbine blade 64 with a low dump pressure, which ensures that the fluid continues to flow through the serpentine cooling passage 90B. To this end, a platform passageway 104 is arranged within the platform 76 and is fluidly interconnected to the second passageway 96 at an end 106, which is generally arranged near the second bend 102 in the example. The platform passageway 104 is generally normal to the second passageway 94. At least one cooling hole 108 fully connects the platform passageway 104 to an exterior surface 110 to provide an exit for the cooling flow near the inner gas flow path, which has a relatively low pressure as compared to the fluid pressure at the inlet 92B. The cooling holes 108 may be any suitable shape, for example, slots, circular, non-circular, linear, non-linear and others. The exterior surface 110 may be provided in on the platform and or blade necks, for example.
The core 112 includes a serpentine core 114 providing the first, second and third passageways 94, 96, 98. The core 112 also includes a platform core 116 corresponding to the platform passageway 104. The serpentine core portion 114 includes an up-pass portion 118 and a down-pass portion 120 that respectively provide the first and second passageways 94, 96. The platform core portion 116 is interconnected to the down pass portion 120 at an intersection 122.
In one an example, the platform passageway 104 is generally perpendicular to the second passageway 96. The first, second and third passageways 94, 96, 98 extend in a radial direction and the platform passageway 104 extends in the circumferential direction A. The serpentine cooling passage 90B may be provided by any number of passes. For example, two passes are shown in
A platform passageway may be provided on either or both of the pressure and suction side portions of the platform 76, as shown in
It should also be understood that although a particular component arrangement is disclosed in the illustrated embodiment, other arrangements will benefit herefrom. Although particular step sequences are shown, described, and claimed, it should be understood that steps may be performed in any order, separated or combined unless otherwise indicated and will still benefit from the present invention.
Although the different examples have specific components shown in the illustrations, embodiments of this invention 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.
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. For that and other reasons, the following claims should be studied to determine their true scope and content.
This application claims priority to U.S. Provisional Application No. 61/879,736, which was filed on Sep. 19, 2013 and is incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2014/055332 | 9/12/2014 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 61879736 | Sep 2013 | US |
