This disclosure relates to cooling for a component of a gas turbine engine, and more particularly to a flow diverter for diverting flow exiting through a platform of a vane.
Gas turbine engines can include a fan for propulsion air and to cool components. The fan also delivers air into an engine core where it is compressed. The compressed air is then delivered into a combustion section, where it is mixed with fuel and ignited. The combustion gas expands downstream and drives turbine blades. Static vanes are positioned adjacent to the turbine blades to control the flow of the products of combustion. The blades and vanes are subject to extreme heat, and thus cooling schemes are utilized for each.
A vane section of a gas turbine engine according to an example of the present disclosure includes a platform and an airfoil extending outwardly from the platform and having an internal channel communicating with an opening in the platform. A rail extends inwardly from the platform, such that a surface of the platform opposite the airfoil and the rail at least partially define a platform cavity. A flow diverter extends inwardly of the platform within the platform cavity and defines a diverter cavity, an inlet configured to receive fluid flowing in a first direction from the opening in the platform to the diverter cavity, and an outlet configured to expel fluid from the diverter cavity to the platform cavity in a second direction different from the first direction.
In a further embodiment according to any of the foregoing embodiments, the flow diverter includes a plurality of sidewalls, a plurality of endwalls, and an endcap.
In a further embodiment according to any of the foregoing embodiments, a sloped surface disposed in the diverter cavity is configured to divert fluid from the first direction to the second direction.
In a further embodiment according to any of the foregoing embodiments, the sloped surface is a concave surface.
In a further embodiment according to any of the foregoing embodiments, the flow diverter includes a wall extending inwardly from the platform, and the outlet is an opening in the wall.
In a further embodiment according to any of the foregoing embodiments, a second opening in the platform is configured to provide fluid communication between the channel and the platform cavity.
In a further embodiment according to any of the foregoing embodiments, a second outlet in the flow diverter is configured to provide fluid communication between the diverter cavity and the platform cavity.
In a further embodiment according to any of the foregoing embodiments, the second outlet is configured to provide impingement flow on the rail.
In a further embodiment according to any of the foregoing embodiments, the outlet is a first outlet. The first outlet is defined by an elongated slot, and the second outlet is defined by a cylindrical hole.
In a further embodiment according to any of the foregoing embodiments, the flow diverter is monolithic with the platform.
In a further embodiment according to any of the foregoing embodiments, the flow diverter is a separate insert received within the opening in the platform.
A gas turbine engine according to an example of the present disclosure includes a turbine section. A vane within the turbine section includes a platform and an airfoil extending outwardly from the platform and having an internal channel communicating with an opening in the platform. A rail extends from the platform such that a surface of the platform opposite the airfoil and the rail at least partially define a platform cavity. A flow diverter extends inwardly of the platform within the platform cavity and defines a diverter cavity, an inlet configured to receive fluid flowing in a first direction from the opening in the platform to the diverter cavity, and an outlet configured to expel fluid from the diverter cavity to the platform cavity in a second direction different from the first direction.
In a further embodiment according to any of the foregoing embodiments, a fluid source is configured to provide fluid flow through the internal channel, through the opening in the platform, and to the diverter cavity.
In a further embodiment according to any of the foregoing embodiments, a sloped surface is disposed in the diverter cavity configured to divert fluid from the first direction to the second direction.
In a further embodiment according to any of the foregoing embodiments, the flow diverter includes a wall extending inwardly from the platform, and the outlet is an opening in the wall.
In a further embodiment according to any of the foregoing embodiments, the first direction has a major component in a radially inward direction from the internal channel to the platform cavity, and the second direction has a major component in a circumferential direction between a pressure side surface of the platform and a suction side surface of the platform.
In a further embodiment according to any of the foregoing embodiments, the first direction has a major component in a radially inward direction from the internal channel to the platform cavity, and the second direction has a major component in an axial direction between a leading edge of the platform and a trailing edge of the platform.
In a further embodiment according to any of the foregoing embodiments, the platform cavity is bound by a support inward of the platform.
In a further embodiment according to any of the foregoing embodiments, a rotor section is axially spaced from the vane section with respect to an engine central longitudinal axis. The support includes an orifice configured to provide fluid communication between the platform cavity and a pressurized cavity provided at least partially by the rotor section.
In a further embodiment according to any of the foregoing embodiments, the flow diverter includes a plurality of sidewalls, a plurality of endwalls, and an endcap, and the outlet is provided by an opening in one of the plurality of sidewalls.
These and other features disclosed herein can be best understood from the following specification and drawings, the following of which is a brief description.
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 first (or low) pressure compressor 44 and a first (or 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 second (or high) pressure compressor 52 and a second (or 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 further supports 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 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 C. 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 engine 20 in one example is a high-bypass geared aircraft engine. In a further example, the engine 20 bypass ratio is greater than about six (6), with an example embodiment being greater than about ten (10), the geared architecture 48 is an epicyclic gear train, such as a planetary gear system or other gear system, with a gear reduction ratio of greater than about 2.3 and the low pressure turbine 46 has a pressure ratio that is greater than about five. In one disclosed embodiment, the engine 20 bypass ratio is greater than about ten (10:1), the fan diameter is significantly larger than that of the low pressure compressor 44, and the low pressure turbine 46 has a pressure ratio that is greater than about five 5:1. Low pressure turbine 46 pressure ratio is pressure measured prior to inlet of low pressure turbine 46 as related to the pressure at the outlet of the low pressure turbine 46 prior to an exhaust nozzle. The geared architecture 48 may be an epicycle gear train, such as a planetary gear system or other gear system, with a gear reduction ratio of greater than about 2.3:1. It should be understood, however, that the above parameters are only exemplary of one embodiment of a geared architecture engine and that the present invention is applicable to other gas turbine engines including direct drive turbofans.
A significant amount of thrust is provided by the bypass flow B due to the high bypass ratio. The fan section 22 of the engine 20 is designed for a particular flight condition—typically cruise at about 0.8 Mach and about 35,000 feet (10,668 meters). The flight condition of 0.8 Mach and 35,000 ft (10,668 meters), with the engine at its best fuel consumption—also known as “bucket cruise Thrust Specific Fuel Consumption (‘TSFC’)”—is the industry standard parameter of lbm of fuel being burned divided by lbf of thrust the engine produces at that minimum point. “Low fan pressure ratio” is the pressure ratio across the fan blade alone, without a Fan Exit Guide Vane (“FEGV”) system. The low fan pressure ratio as disclosed herein according to one non-limiting embodiment is less than about 1.45. “Low corrected fan tip speed” is the actual fan tip speed in ft/sec divided by an industry standard temperature correction read [(Tram ° R)/(518.7° R)]{circumflex over ( )}0.5. The “Low corrected fan tip speed” as disclosed herein according to one non-limiting embodiment is less than about 1150 ft/second (350.5 meters/second).
The vane section 61 includes a platform 63 having a forward rail 70 and an aft rail 72 extending inwardly from the platform 63, the example being in the radially inward direction with respect to the engine central longitudinal axis A. The platform 63 and rails 70, 72 define a platform cavity 78. A fluid source 84 communicates fluid flow FS through the outer platform 64, through an internal channel 86 of the airfoil section 62, through an opening 88 in the platform 63 aligned with the channel 86, and into the platform cavity 78. In the example, the fluid may then exit the platform cavity 78 through an orifice 83 in a support 80, which is a seal in one non-limiting example, radially inward of the platform 63 and providing a radially inner boundary of the platform cavity 78. The fluid may exit through the orifice 83 to the pressurized cavity 85 between adjacent rotor disks 66. Although examples in this disclosure are directed to the inner platform 63, the outer platform 64 may also benefit from the teachings herein, such as in an arrangement where fluid is provided outwardly through the platform 63, through the channel 86, and through the outer platform 64.
The example flow diverter 290 is provided by a first sidewall 295, a second sidewall 296, a leading edge endwall 297, and a trailing edge endwall 298 extending outwardly from an endcap 294 to the platform 263. The endcap 294, first sidewall 295, second sidewall 296, leading edge endwall 297, and trailing edge endwall 298 may be provided by separate components attached to one another or by one or more monolithic pieces. In some examples, the first sidewall 295, the second sidewall 296, the leading edge endwall 297, and the trailing edge endwall 298 form an airfoil-shaped structure complementary to the shape of the airfoil section 262. The example outlet 293 is provided in the first sidewall 295, but may alternatively or additionally be provided in the second sidewall 296, the leading edge endwall 297, the trailing edge endwall 298, or the endcap 294. The example outlet 293 is an axially elongated slot in the sidewall 295, but other shapes of openings, including but not limited to cylindrical holes, are contemplated.
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The example deflecting surface 504 is a concave surface curving toward the outlet 593 as it extends toward the endcap 594. Other sloped surfaces may be utilized. The example deflecting surface 504 is provided by a cast part 506 that abuts the sidewall 596 and endcap 594. Alternatively, the cast part 506 may be cast as monolithic with the sidewall 596, the endcap 594 or both. In another example, the deflecting surface 504 may be provided by a sheet metal feature attached to one or both of the sidewall 596 and the endcap 594. The deflecting surface 504 may condition fluid flowing across it. The deflecting surface 504 is configured to smoothly transition the flow from a first direction to a second direction, reducing turbulent eddies in areas such as corners of the flow diverter cavity 591 that cause high pressure loss.
The example deflecting surfaces 604A/604B are concave surfaces curving toward their respective outlets 693A/693B as they extend inward toward the endcap 694, but other sloped surfaces may be utilized. The example deflecting surfaces 604A/604B are provided by a cast part 606 that abuts the endcap 694. Alternatively, the cast part 606 may be cast as monolithic with the endcap 694. In another example, the surfaces 604A/604B may be provided by sheet metal features attached to the endcap 694.
It should be understood that relative positional terms such as “forward,” “aft,” “upper,” “lower,” “above,” “below,” and the like are with reference to the normal operational attitude of the vehicle and should not be considered otherwise limiting.
Although the different examples have the specific components or features 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.
One of ordinary skill in this art would understand that the above-described embodiments are exemplary and non-limiting. That is, modifications of this disclosure would come within the scope of the claims. Accordingly, the following claims should be studied to determine their true scope and content.
This invention was made with Government support under W58RGZ-16-C-0046 awarded by the United States Army. The Government has certain rights in this invention.