Engine component

An engine component includes a hot surface in thermal communication with a hot combustion gas flow, and a cooling surface, opposite the hot surface, along which a cooling fluid flows. At least one vortex generator is provided on the cooling surface, and can induce a vortex in the cooling fluid in response to contact with the flowing cooling fluid.

BACKGROUND OF THE INVENTION

Turbine engines, and particularly gas or combustion turbine engines, are rotary engines that extract energy from a flow of combusted gases passing through the engine onto a multitude of turbine blades. Gas turbine engines have been used for land and nautical locomotion and power generation, but are most commonly used for aeronautical applications such as for aircraft, including helicopters. In aircraft, gas turbine engines are used for propulsion of the aircraft. In terrestrial applications, turbine engines are often used for power generation.

Gas turbine engines for aircraft are designed to operate at high temperatures to maximize engine efficiency, so cooling of certain engine components, such as the high pressure turbine and the low pressure turbine, may be necessary. Typically, cooling is accomplished by ducting cooler fluid from the high and/or low pressure compressors to the engine components which require cooling. Temperatures in the high pressure turbine are around 1000° C. to 2000° C. and the cooling fluid from the compressor is around 500° C. to 700° C. While the compressor air is a high temperature, it is cooler relative to the turbine air, and may be used to cool the turbine.

Interior cavities of engine components that receive cooling fluid have been provided with turbulators in order to generate turbulence in the cooling fluid and enhance heat transfer.

BRIEF DESCRIPTION OF THE INVENTION

The invention relates to an engine component for a gas turbine engine generating a hot combustion gas flow.

In one aspect, the invention relates to an engine component having a hot surface in thermal communication with the hot combustion gas flow, a cooling surface, opposite the hot surface, and defining a cooling area having a cross-sectional width along which a cooling fluid flows in a flow direction, and at least one vortex generator extending from the cooling surface and located in the cooling area, and having a body length, a body width, and a body axis. The body length is greater than the body width and extends along the body axis. The body axis is substantially aligned with the flow direction. The body width is less than the cross-sectional width of the cooling area. The vortex generator is shaped to induce a vortex in the cooling fluid in response to contact with the flowing cooling fluid.

In another aspect, the invention relates to an engine component having a cavity at least partially defining a cooling surface along which a cooling fluid flows in a flow direction, the cavity having a length, a cross-sectional width, and a cross-sectional height, wherein the length is greater than the cross-sectional width, a hot surface, opposite the cooling surface, in thermal communication with the hot combustion gas flow, and at least one vortex generator extending from the cooling surface and having a body length, a body width, a body height, and a body axis. The body length is greater than the body width and extends along the body axis. The body axis is substantially aligned with the flow direction. The body length is 5-15% of the length of the cavity. The body width is 10-35% of the cross-sectional width of the cavity. The body height is 20-75% of the cross-sectional height of the cavity.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The described embodiments of the present invention are directed to cooling an engine component, particularly in a turbine engine. For purposes of illustration, the present invention will be described with respect to an aircraft gas turbine engine. It will be understood, however, that the invention is not so limited and may have general applicability in non-aircraft applications, such as other mobile applications and non-mobile industrial, commercial, and residential applications.

FIG. 1is a schematic cross-sectional diagram of a gas turbine engine10for an aircraft. The engine10has a generally longitudinally extending axis or centerline12extending forward14to aft16. The engine10includes, in downstream serial flow relationship, a fan section18including a fan20, a compressor section22including a booster or tow pressure (LP) compressor24and a high pressure (HP) compressor26, a combustion section28including a combustor30, a turbine section32including a HP turbine34, and a LP turbine36, and an exhaust section38.

The fan section18includes a fan casing40surrounding the fan20. The fan20includes a plurality of fan blades42disposed radially about the centerline12.

The HP compressor26, the combustor30, and the HP turbine34form a core44of the engine10which generates combustion gases. The core44is surrounded by core casing46which can be coupled with the fan casing40.

A HP shaft or spool48disposed coaxially about the centerline12of the engine10drivingly connects the HP turbine34to the HP compressor26. A LP shaft or spool50, which is disposed coaxially about the centerline12of the engine10within the larger diameter annular HP spool48, drivingly connects the LP turbine36to the LP compressor24and fan20.

The LP compressor24and the HP compressor26respectively include a plurality of compressor stages52,54, in which a set of compressor blades56,58rotate relative to a corresponding set of static compressor vanes60,62(also called a nozzle) to compress or pressurize the stream of fluid passing through the stage. In a single compressor stage52,54, multiple compressor blades56,58may be provided in a ring and may extend radially outwardly relative to the centerline12, from a blade platform to a blade tip, while the corresponding static compressor vanes60,62are positioned downstream of and adjacent to the rotating blades56,58. It is noted that the number of blades, vanes, and compressor stages shown inFIG. 1were selected for illustrative purposes only, and that other numbers are possible.

The HP turbine34and the LP turbine36respectively include a plurality of turbine stages64,66, in which a set of turbine blades68,70are rotated relative to a corresponding set of static turbine vanes72,74(also called a nozzle) to extract energy from the stream of fluid passing through the stage. In a single turbine stage64,66, multiple turbine blades68,70may be provided in a ring and may extend radially outwardly relative to the centerline12, from a blade platform to a blade tip, while the corresponding static turbine vanes72,74are positioned upstream of and adjacent to the rotating blades68,70. It is noted that the number of blades, vanes, and turbine stages shown inFIG. 1were selected for illustrative purposes only, and that other numbers are possible.

In operation, the rotating fan20supplies ambient air to the LP compressor24, which then supplies pressurized ambient air to the HP compressor26, which further pressurizes the ambient air. The pressurized air from the HP compressor26is mixed with fuel in combustor30and ignited, thereby generating combustion gases. Some work is extracted from these gases by the HP turbine34, which drives the HP compressor26. The combustion gases are discharged into the LP turbine36, which extracts additional work to drive the LP compressor24, and the exhaust gas is ultimately discharged from the engine10via the exhaust section38. The driving of the LP turbine36drives the LP spool50to rotate the fan20and the LP compressor24.

Some of the ambient air supplied by the fan20may bypass the engine core44and be used for cooling of portions, especially hot portions, of the engine10, and/or used to cool or power other aspects of the aircraft. In the context of a turbine engine, the hot portions of the engine are normally downstream of the combustor30, especially the turbine section32, with the HP turbine34being the hottest portion as it is directly downstream of the combustion section28. Other sources of cooling fluid may be, but is not limited to, fluid discharged from the LP compressor24or the HP compressor26.

FIG. 2is a side section view of the combustor30and HP turbine34of the engine10fromFIG. 1. The combustor30includes a deflector76and a combustor liner77. Adjacent to the turbine blade68of the turbine34in the axial direction are sets of static turbine vanes72, with adjacent vanes72forming nozzles therebetween. The nozzles turn combustion gas an that the maximum energy may be extracted by the turbine34. A cooling fluid flow C passes through the vanes72to cool the vanes72as hot combustion gas H passes along the exterior of the vanes72. A shroud assembly78is adjacent to the rotating blade68to minimize flow loss in the turbine34. Similar shroud assemblies can also be associated with the LP turbine36, the LP compressor24, or the HP compressor26.

One or more of the engine components of the engine10has a surface in which various cooling embodiments disclosed further herein may be utilized. Some non-limiting examples of the engine component having a cooled surface can include airfoils such as the blades68,70, vanes or nozzles72,74, the combustor deflector76, the combustor liner77, or the shroud assembly78, described inFIGS. 1-2.

FIG. 3is perspective view of an engine component in the form of one of the turbine blades68of the engine10fromFIG. 1. The turbine blade68includes a shank80and an airfoil blade82. The shank80further includes a blade platform84, which helps to radially contain the turbine air flow, and a dovetail86, which attaches to a turbine rotor disk (not shown). The airfoil blade82has a concave-shaped pressure side88and a convex-shaped suction side90which are joined together to define an airfoil shape. A longitudinal axis92extends radially outward toward a blade tip94and radially inward toward a blade root96which is attached to the shank80. The blade68rotates in a direction such that the pressure side88follows the suction side90. Thus, as shown inFIG. 3, the blade68would rotate into the page.

FIG. 4is a cross-sectional view of the airfoil blade82of the turbine blade68, taken along line IV-IV ofFIG. 3. The airfoil blade82includes a plurality of generally longitudinally extending internal cavities in the form of cooling passages98which direct a flow of cooling fluid therethrough. The cooling passages98may be interconnected to define at least a portion of a coolant circuit through the blade68. It will be seen inFIG. 4that each of cooling passages98can have a unique cross-section, ranging from substantially rectangular to nearly trapezoidal, although the cross-section of such cooling passages98may have any shape. During operation, the coolant circuit receives cooling fluid from an inlet in the shank80, and, after coursing through the cooling passages98, the cooling fluid exits the airfoil blade82through film holes.

In accordance with one embodiment of the present invention, at least one vortex generator102is provided within at least one of the cooling passages98. The vortex generator102can extend from a cooling surface of the cooling passage98to induce a vortex, in cooling fluid flowing through the cooling passage98. InFIG. 4, only one cooling passage98is shown as having a vortex generator102, although it is understood that more or all of the cooling passages98can be provided with vortex generators102. Further, while vortex generators102are shown on the suction side90of the airfoil blade82, it is understood that vortex generators102can be provided on an interior wall or the pressure side88of the airfoil blade82.

FIG. 5is a close-up view of one of the cooling passages98fromFIG. 4. The vortex generator102can extend from a cooling surface of the cooling passage98to induce a vortex, generally indicated by arrows inFIG. 5, in cooling fluid flowing through the cooling passage98, in response to contact with the flowing cooling fluid. As noted above, the cooling passage98can have various cross-sectional shapes; as shown and described, the present cooling passage98is substantially quadrilateral in shape with four side walls104,106,108,110defining the cross-sectional shape. In the present example, the first wall104may be defined by the suction side90of the blade68, with the suction side90defining a hot surface of the blade68that is in in thermal communication with a hot combustion gas flow and the interior of the wails104,106,108,110defining a cooling surface of the blade68that is opposite the hot surface along which the cooling fluid flows. In the case of a gas turbine engine, the hot surface may be exposed to gases having temperatures in the range of 1000° C. to 2000° C., Suitable materials for the walls104,106,108,110include, but are not limited to, steel, refractory metals such as titanium, or super alloys based on nickel, cobalt, or iron, and ceramic matrix composites.

The vortex generator102is provided on one or more walls104,106,108,110of the cooling passage98. In the illustrated embodiment, the vortex generator102is provided on the interior wall104that is diametrically opposite the suction side90, with the interior wall104defining a cooling area in which the vortex generator102is located. It is understood that the vortex generators102could be on combination of the walls104,106,108,110of the cooling passage98as well.

FIG. 6is a perspective view ofFIG. 5. The vortex generators102can have a three-dimensional body112having a body length L1, a body width W1, and a body height H1. The body112defines a body axis X, and the body length L1can be measured along the body axis X. The body width W1can be measured perpendicularly to the body axis X. The body height141can be measured from the interior wall104.

The cooling passage98can have a cross-sectional width W2and a cross-sectional height H2. The cross-sectional width W2can be measured between the wails104,106, while the cross-sectional height H2can be measured between the walls108,110.

The body112of the vortex generator102can vary in contour. As illustrated, the body112has a leading surface114, a trailing surface116, and opposing side surfaces118joining the leading and trailing surfaces114,116. The side surfaces118can further be joined by a top surface120. In the illustrated embodiment, the body112is contoured such that the side surfaces118taper toward each other toward the top surface120. The side surfaces118can be substantially identical such that the body112is symmetrical when viewed down the body axis X, or can differ, such that the body112is asymmetrical when viewed down the body axis X. Also, the leading and trailing surfaces114,116can be substantially identical such that the body112is symmetrical along the body axis X, or can differ, such that the body112is asymmetrical along the body axis X.

For the illustrated body112, the body length L1is defined by the distance between the leading and trailing surfaces114,116, the body width W1is defined by the distance between the side surfaces118, and the body height H1is defined as the distance from the interior wall104to the top surface120. More specifically, the body length L1can be the maximum distance between the leading and trailing surfaces114,116, the body width W1can be the maximum distance between the side surfaces118, and the body height H1can be the maximum distance from the interior wall104to the top surface120.

It is noted that the cooling passage98can include multiple vortex generators102; in the illustrated embodiment, two side-by side vortex generators102are shown. In embodiments where multiple vortex generators102are provided in a cooling passage98, the vortex generators102can each have a substantially constant body height H1so that they extend into the cooling passage98a substantially constant amount. Also, such vortex generators102have a substantially constant body length L1, body width W1, orientation, and/or body contour. Alternatively, the vortex generators102may differ from each other in one or more of these respects.

FIG. 7is a perspective view of a portion of the interior of the cooling passage98with a wall106defining the cooling passage98removed for clarity. The cooling passage98can include multiple vortex generators102located within the cooling area defined by the passage98and arranged along the length of the passage98. The cooling passage98further has a passage length L2. The passage length L2can be measured in the flow direction of the cooling fluid through the cooling passage98, generally indicated by arrow C. In the present embodiment, the cooling passage98is elongated, such that the passage length L2is greater than the cross-sectional width W2, as well as the cross-sectional height H2(seeFIG. 6); it is noted that the full height H2of the cooling passage98is not shown inFIG. 7.

With reference toFIGS. 5 and 6, the shape of the vortex generator102, including the orientation and dimensions of the vortex generator102relative to the cooling passage98, impacts the performance of the vortex generator102in inducing vortices in the cooling fluid. For example, the vortex generator102can further be elongated in the flow direction C, such that the body length L1is greater than the body width W1. Still further, the vortex generator102does not span the cooling area, such that the body width W1of the vortex generator102is less than the cross-sectional width W2of the cooling passage98. Likewise, the body height H1of the vortex generator102is less than the cross-sectional height H2of the cooling passage98.

In one more specific embodiment, the vortex generator102can have a body height H1that is 20-75% of the cross-sectional height H2of the cooling passage98, a body length L1that is 5-15% of the length of the cooling passage98, a body width W1that is 10-35% of the cross-sectional width W2of the cooling passage98, or any combination of these dimensions. A vortex generator within these ranges can generate sufficient vortices in the cooling flow to augment heat transfer, white avoiding high pressure losses and locally high Mach numbers. It is noted that these dimensions are representative of an aircraft engine turbine blade, and that the dimensions may vary in other applications of the vortex generators.

FIG. 8is a top view showing some exemplary orientations for the vortex generator102within the cooling passage98. In each illustrated example, the vortex generators102are arranged in two rows that extend in substantially the same direction as the flow direction C, with each row having multiple vortex generators102. However, in other examples, the cooling passage98can be provided with greater or fewer rows of vortex generators102.

In the first illustrated example (a), which is the same as shown inFIGS. 5 and 6, the vortex generators102can be oriented substantially in line with the flow direction C, such that body axis X can be substantially aligned with the flow direction C. By “substantially aligned,” the body axis X can be offset by 15 degrees or less from the flow direction C. More specifically, in example (a) the body axis X is parallel to the flow direction C; in other words, the body axis X is offset by 0 degrees from the flow direction C. As such, the vortex generators102in a single row lie along collinear body axes X. Further, vortex generators102in different rows are aligned with each other.

In the second illustrated example (b), the body axis X of each vortex generator102is parallel to the flow direction C, but are staggered along the flow direction C such that alternating vortex generators102in a single row lie along parallel, but not collinear, body axes X. As such, the rows are staggered relative to each other in a direction substantially perpendicular to the flow direction C. Vortex generators102in different rows are aligned with each other.

In the third illustrated example (c), the body axis X of each vortex generator102is offset by approximately 10 degrees from the flow direction C. As such, each vortex generator102in a single row lie along parallel, but not collinear, body axes X. Further, the vortex generators102in different rows are aligned with each other; however, the body axis X of the vortex generator102in one row is non-parallel to the body axis X of the aligned vortex generator102in the other row.

In the fourth illustrated example (d), the body axis X of each vortex generator102is parallel to the flow direction C and the vortex generators102are aligned along the flow direction C along collinear body axes X, but vortex generators102in different rows are staggered along the flow direction C such that the rows are offset from each other.

FIG. 9is a cross-sectional view of the vortex generators102taken along line VIII-VIII ofFIG. 7. The leading surface114faces upstream relative to the flow direction C and the trailing surface1116faces downstream relative to the flow direction C. The leading and trailing surfaces114,116extend from the wall104at an angle to converge with the top surface120. In the illustrated embodiment, the body112has an airfoil shape and is contoured such that the angle defined by the leading surface114is steeper than the angle defined by the trailing surface116.

In the art of cooling engine components, prior art patents have conflated the terms vortex generators and turbulators, even when it was incorrect to do so. For purposes of this disclosure, it is important to clarify the difference between vortex generators and turburlators and to properly define a vortex generator because this disclosure is directed to vortex generators, not to turbulators.FIGS. 10-11show a comparison of a cooling passage98provided with the vortex generators102to a cooling passage98provided with conventional turbulators122, respectively. The turbulators122are typically rectangular in shape, are oriented across the cooling passage98, and are spaced apart in the direction of cooling fluid flow. In the present embodiment, the turbulators122are perpendicular to the flow direction, but may also be at an angle to the flow direction, such as 45 degrees. The vortex generators102can increase the internal heat transfer surface area SA in comparison to the turbulators122/ The heat transfer surface area SA can be defined as the surface area of the cooling surface in the cooling passage98; in the present embodiment, the heat transfer surface area SA is the combined surface area of the walls104,106,108,110and the surface area of the vortex generators or turbulators122. For illustration purposes, each passage98is shown inFIGS. 10-11with a dotted line generally indicating the heat transfer surface area SA, although it is understood that the cross-section does not show the entire heat transfer surface area SA of the passages98. The larger heat transfer surface area SA provided by the vortex generators102produces a higher heat transfer performance than the turbulators122.

The cooling passages98further define a flow area where the flow area FA is the open cross-sectional arear of the cooling passage98through which cooling fluid can flow. For illustration purposes, each passage98is shown inFIGS. 10-11with a dotted pattern generally indicating the flow area FA. In the example illustrated herein, the cooling passage98containing the vortex generators102has the same flow area FA as the cooling passage98containing the turbulators122, however, the heat transfer surface area SA for the cooling passage98with the vortex generators102can be 40-60% greater than that for the turbulators122because the axial orientation of the vortex generators102allows greater penetration of the vortex generators102into the cooling fluid flow. The turbulators122cannot be configured to match the penetration of the vortex generators102, because this would impact the flow area FA.

The turbulators122increase the heat transfer coefficients within the cooling passage98primarily by maintaining the turbulence of the cooling air as it flows over each of the turbulators122. As the turbulators122are generally transverse to the flow direction, particles in the cooling flow tend to collect in recirculating flow regions just upstream and downstream of the turbulators122. The vortex generators102, in contrast to the turbulators122, tend to increase the heat transfer coefficients by generating vortices that extend downstream with the cooling flow. Particles entrained in the cooling flow tend to follow the streamlines of the vortices and do not accumulate as they do with turbulators. Further, the vortex generators102are not generally transverse to the cooling air flow, which further lessens the likelihood any entrained particles accumulating in specific regions. Finally, the vortex generators102tend to have a more aerodynamic shape with the body axis being generally parallel to the cooling air flow.

The body contour of the vortex generator can also impact the performance of the vortex generator. Some non-limiting examples of different body contours for vortex generators according to further embodiments of the invention are shown inFIG. 12. The body contour of a vortex generator can be defined by its cross-sectional shape and/or its planform. The cross-sectional shape can be viewed in a plane orthogonal to the body axis X of the vortex generator. The planform is the contour of the vortex generator as viewed from above a cooling surface124of an engine component126from which the vortex generators projects. It is understood that the dimensions and orientations of the vortex generators shown inFIG. 12may conform with those discussed above with reference toFIGS. 5-9, or may differ. Further, as discussed above with respect toFIG. 2, the engine component can comprise one of an airfoil, a nozzle, a vane, a blade, a shroud, a combustor liner, or a combustor deflector.

Some non-limiting examples of cross-sectional shapes include rectangular, triangular, and trapezoidal, and may be at least partially defined by the shape of the leading and trailing surfaces of the vortex generator. Some non-limiting examples of shapes for the leading the trailing surfaces include ramped, wedged, or rounded. For example, the leading surfaces of vortex generators128,136,140,142are ramped; those of vortex generators130,132,134,138are wedged; and those of vortex generators144,148are rounded. The trailing surfaces of vortex generators118,130,134,136,138,140are ramped; those of vortex generators132,142are wedged; and those of vortex generators144,148are rounded. The ramped, wedged, or rounded surfaces help maintain a high cooling fluid velocity along the cooling surface124which can reduce the tendency for dust to accumulate on the cooling surface124.

Some non-limiting examples of planforms include rectangular, trapezoidal, diamond-shaped, kite-shaped, teardrop-shaped, ovoid, elliptical, pentagonal, hexagonal, and heptagonal. For example, the vortex generator128has a generally trapezoidal planform, the vortex generators130,134have a generally pentagonal planform, the vortex generator132has a generally hexagonal planform, the vortex generators136,142have a generally heptagonal planform, the vortex generator138has a generally kite-shaped planform, the vortex generator140has a generally rectangular planform, the vortex generator144has a generally teardrop-shaped planform, and the vortex generator146has a generally elliptical planform.

In one embodiment, the vortex generator138having a generally kite-shaped planform with a wedged leading surface and a ramped trailing surface allows for smatter vortices to initiate at the leading surface and grow along the diverging and expanding side walls that intersect the cooling surface124. The kite-shaped planform presents a small initial disturbance to the cooling fluid flow that grows naturally as a vortex on both side walls.

In any of the above embodiments, it is understood that while the drawings may show the vortex generators having sharp corners, edges, and/or transitions with the cooling surface for purposes of illustration, is may be more practical for the corners, edges, and/or transitions to be smoothly radiused or filleted. Furthermore, embodiments of the vortex generators illustrated as having smoothly radiused or filleted corners, edges, and/or transitions with the cooling surface may instead have sharp corners, edges, and/or transitions.

In any of the above embodiments, while the vortex generators are primarily shown on one surface defining the cooling area, the location of the vortex generators is not so limited. The vortex generators may be located on multiple surfaces defining the cooling area. For example, they may be located on opposing surfaces, adjacent surfaces, or all of the surfaces for that matter. The vortex generators may also be located on a surface extending into or from the surfaces defining the cooling area. The vortex generators are not limited to being located on the surfaces defining the cooling area. Some of the vortex generators may be both in an area not defining the cooling area and in the cooling area, for example.

The various embodiments of systems, methods, and other devices related to the invention disclosed herein provide improved cooling for turbine engine components. One advantage that may be realized in the practice of some embodiments of the described systems is that vortex generators are provided for the walls and/or interior cavities of engine components in order to improve the cooling of the engine component. The vortex generators induce strong vortices in the cooling fluid flow, which in turn produces high internal heat transfer coefficient augmentation, in addition to providing a large internal heat transfer area. This effectiveness can increase the time-on-wing (TOW) for the turbine engine and the service life of these parts can be increased.

In a further advantage of the invention, the vortex generators can be used instead of conventional turbulators, and can produce internal heat transfer coefficients comparable to conventional turbulators, but with much higher coolant-side area enhancement.