Airfoil profile

Description

TECHNICAL FIELD

The present invention generally relates to axial compressor components having an airfoil. More specifically, the present invention relates to an airfoil profile for compressor components, such as blades and/or vanes, that have a variable thickness and three-dimensional (“3D”) shape along the airfoil span in order to raise the natural frequency, improve airfoil mean stress and dynamic stress capabilities of the compressor component, and minimize risk of failure due to cracks caused by excitation of the component.

BACKGROUND

Gas turbine engines, such as those used for power generation or propulsion, include a compressor section. The compressor section includes a casing and a rotor that rotates about an axis within the casing. In axial-flow compressors, the rotor typically includes a plurality of rotor discs that rotate about the axis. A plurality of compressor blades extend away from, and are radially spaced around, an outer circumferential surface of each of the rotor discs. Typically, following each plurality of compressor blades is a plurality of compressor vanes. The plurality of compressor vanes usually extend from, and are radially spaced around, the casing. Each set of a rotor disc, a plurality of compressor blades extending from the rotor disc, and a plurality of compressor vanes immediately following the plurality of compressor blades is generally referred to as a compressor stage. The radial height of each successive compressor stage decreases because the blades and vanes increase the density, pressure and temperature of air passing through the stage. Specialized shapes of compressor blades and compressor vanes aid in compressing fluid as it passes through the compressor.

Compressor components, such as compressor blades and stator vanes, have an inherent natural frequency. When these components are excited by the passing air, as would occur during normal operating conditions of a gas turbine engine, the compressor components vibrate at different orders of engine rotational frequency. When the natural frequency of a compressor component coincides with or crosses an engine order, the compressor component can exhibit resonant vibration that in turn can cause cracking and ultimately failure of the compressor component.

SUMMARY

This summary is intended to introduce a selection of concepts in a simplified form that are further described below in the detailed description section of this disclosure. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in isolation to determine the scope of the claimed subject matter.

In brief, and at a high level, this disclosure describes gas turbine engine components, e.g., compressor components such as blades and vanes, having airfoil portions that optimize the interaction with other compressor stages, provide for aerodynamic efficiency, and meet aeromechanical life objectives. More specifically, the compressor components described herein have unique airfoil thicknesses, chord lengths, and 3D shaping that results in the desired natural frequency of the respective compressor component. Further, the airfoil thicknesses and 3D shaping at specified radial distances along the airfoil span may provide an acceptable level of mean stress in the airfoil sections, and also provide improved vane aerodynamics and efficiency while maintaining the desired vane natural frequency. The airfoil portion of the compressor components disclosed herein, such as blades or vanes, have a particular shape or profile as specified herein. For example, one such airfoil profile may be defined by at least some of the Cartesian coordinate values of X, Y, and Z set forth in Table 1. In this example, the Z coordinate values are distances measured perpendicular to the compressor centerline and the X and Y coordinate values for each Z distance define an airfoil section when the coordinate values are connected with smooth continuing arcs. In this example, the airfoil sections at each Z distance are further joined with smooth continuing arcs to define the 3D shape of the airfoil portion of the compressor component.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments disclosed herein relate to compressor component airfoil designs and are described in detail with reference to the attached drawing figures, which illustrate non-limiting examples of the disclosed subject matter, wherein:

FIG. 1 depicts a schematic view of a gas turbine engine, in accordance with aspects hereof;

FIG. 2 depicts a perspective view of a set of compressor vanes coupled to a compressor casing, in accordance with aspects hereof;

FIG. 3 depicts a perspective view of a portion of the compressor casing of FIG. 2 and a compressor vane coupled thereto, in accordance with aspects hereof;

FIG. 4 depicts a top view of a compressor component, in accordance with aspects hereof;

FIG. 5 depicts a perspective view of a pressure side of the compressor component of FIG. 4, in accordance with aspects hereof;

FIG. 6 depicts a perspective view of a suction side of the compressor component of FIG. 4, in accordance with aspects hereof;

FIG. 7 depicts a cross-section of the compressor component of FIG. 4 taken along cut-line 7-7 in FIG. 5, in accordance with aspects hereof; and

FIG. 8 depicts a perspective view of the airfoil sections defined by the Cartesian coordinate values of X, Y, and Z set forth in Table 1, in accordance with aspects hereof.

DETAILED DESCRIPTION

The subject matter of this disclosure is described herein to meet statutory requirements. However, this description is not intended to limit the scope of the invention. Rather, the claimed subject matter may be embodied in other ways, to include different steps, combinations of steps, features, and/or combinations of features, similar to those described in this disclosure, and in conjunction with other present or future technologies.

In brief, and at a high level, this disclosure describes gas turbine engine components, e.g., compressor components such as blades and vanes, having airfoil portions that may optimize the interaction with other compressor stages, provide for aerodynamic efficiency, and improve aeromechanical life objectives. More specifically, the compressor components described herein may have, in different disclosed aspects, unique airfoil thicknesses, chord lengths, and 3D shaping that results in different performance characteristics being achieved, such as, e.g., an altered natural frequency of the associated compressor component. Further, the airfoil thicknesses and 3D shaping at specified radial distances along the airfoil span may provide an acceptable level of mean stress in the airfoil sections, and also provide improved vane aerodynamics and efficiency. The airfoil portion of the compressor components disclosed herein, such as blades or vanes, have a particular shape or profile as specified herein. For example, one such airfoil profile may be defined by the Cartesian coordinate values of X, Y, and Z set forth in Table 1. In this example, the Z coordinate values are distances measured perpendicular from the compressor centerline and the X and Y coordinate values at each Z distance define an airfoil section when the coordinate values are connected with smooth continuing arcs. In this example, the airfoil sections at each Z distance may be joined with smooth continuing arcs to define the 3D shape of the airfoil portion of the compressor component.

Referring now to FIG. 1, there is illustrated a portion of a compressor 10 having multiple compressor stages, including a stage zero 12 at the front of the compressor 10. Each compressor stage includes a rotor disc 14, a plurality of circumferentially spaced compressor blades 16 coupled to the rotor disc 14, and a plurality of compressor vanes 18 adjacent to, and following, the plurality of circumferentially spaced compressor blades 16. The plurality of compressor vanes 18 are circumferentially spaced around, and extend from, a casing 20 of the compressor 10.

One aspect of a compressor component is a compressor vane 16A, as depicted in FIGS. 2-6. As best seen in FIG. 3, the compressor vane 16A includes a root portion 22 configured to be coupled to the casing 20, and an airfoil portion 26 extending from the root portion 22 to a tip 28. As best seen in FIGS. 5 and 6, the airfoil portion 26 generally includes a leading edge 30, a trailing edge 32, and a pressure side wall 34 and a suction side wall 36 each extending between the leading edge 30 and the trailing edge 32. The pressure side wall 34 generally presents a convex surface along the span of the airfoil portion 26. The suction side wall 36 generally presents a concave surface along the span of the airfoil portion 26.

A compressor component may be used in a land-based compressor in connection with a land-based gas turbine engine. Typically, compressor components in such a compressor only experience temperatures below approximately 850 degrees Fahrenheit. As such, these types of compressor components may be fabricated from a relatively low temperature alloy. For example, these compressor components may be made from a stainless-steel alloy.

A cross-section of one aspect of the airfoil portion 26 is depicted in FIG. 7. As seen in FIG. 7, a chord 40 is shown for this radial section of the airfoil portion 26. The thickness of the airfoil portion 26 (e.g., the distance between the pressure side wall 34 and the suction side wall 36) varies at each point along the chord 40. As is evident from FIGS. 4-6, the length and orientation of the chord 40 changes along the span of the airfoil portion 26.

By changing the airfoil thickness, chord, 3D shaping, and/or the distribution of material along the span of the airfoil portion 26 of the compressor component, the natural frequency of the compressor component may be altered. This may be advantageous for the operation of the compressor 10. For example, during operation of the compressor 10, the compressor component may move (e.g., vibrate) at various modes due to the geometry, temperature, and aerodynamic forces being applied to the compressor component. These modes may include bending, torsion, and various higher-order modes.

If excitation of the compressor component occurs for a prolonged period of time with a sufficiently high amplitude then the compressor component can fail due to high cycle fatigue. For example, a critical first bending mode frequency of a compressor component may be approximately twice the 60 Hz rotation frequency of the gas turbine engine. For this mode, the first bending mode must avoid the critical frequency ranges of 55-65 Hz and 110-130 Hz to prevent resonance of the bending mode with the excitation associated with compressor (or engine) rotation. Modifying the thickness, chord, and/or the 3D shape of the compressor component, and in particular that of the airfoil portion thereof, results in altering the natural frequency of the compressor component. Continuing with the above example, modifying the thickness, chord, and/or the 3D shape of the compressor component in accordance with the disclosure herein may result in the first bending natural frequency being shifted to be between 65 Hz and 110 Hz, in accordance with some aspects. In other aspects, the first bending natural frequency may be shifted to be between about 70 Hz to about 105 Hz. This first bending natural frequency of the compressor component will therefore be between the 1^st and 2^nd engine order excitation frequencies when the compressor is rotating at 60 Hz. More specifically, a compressor component having the thickness, chord, and/or the 3D shape as defined by the Cartesian coordinates set forth in Table 1 will have a natural frequency of first bending between 1^st and 2^nd engine order excitations. In other aspects, a compressor component having the thickness, chord, and/or the 3D shape as defined by the Cartesian coordinates set forth in Table 1 will have a natural frequency of first bending at least 5-10% greater than 1^st engine order excitations and at least 5-10% less than 2^nd engine order excitations. In fact, a compressor component having the thickness, chord, and/or the 3D shape as defined by the Cartesian coordinates set forth in Table 1 will have a natural frequency for the lowest few vibration modes of at least 5-10% less than or greater than each engine order excitation. For example, the compressor component may have a natural frequency 12% less than the 2^nd engine order excitation when the compressor is rotating at 60 Hz.

In one embodiment disclosed herein, a nominal 3D shape of an airfoil portion, such as the airfoil portion 26 shown in FIGS. 5 and 6, of a gas turbine engine component, such as a compressor component of a gas turbine engine, may be defined by a set of X, Y, and Z coordinate values measured in a Cartesian coordinate system. For example, one such set of coordinate values are set forth, in inches, in Table 1 below. The Cartesian coordinate system includes orthogonally related X, Y, and Z axes. The positive X, Y, and Z directions are axial toward the exhaust end of the compressor, tangential in the direction of engine rotation, and radially outward toward the static case, respectively. Each Z distance is measured from an axially-extending centerline of the compressor 10 (which, in aspects, may also be a centerline of the gas turbine engine). The X and Y coordinates for each distance Z may be joined smoothly (e.g., such as by smooth continuing arcs, splines, or the like) to thereby define a section of the airfoil portion of the compressor component at the respective Z distance. Each of the sections of the airfoil portion from the coordinate values set forth in Table 1 below is shown in FIG. 8. Each of the defined sections of the airfoil profile is joined smoothly with an adjacent section of the airfoil profile in the Z direction to form a complete nominal 3D shape of the airfoil portion.

The coordinate values set forth in Table 1 below are for a cold condition of the compressor component (e.g., non-rotating state and at room temperature). Further, the coordinate values set forth in Table 1 below are for an uncoated nominal 3D shape of the compressor component. In some aspects, a coating (e.g., corrosion protective coating) may be applied to the compressor component. The coating thickness may be up to about 0.010 inches thick.

Further, the compressor component may be fabricated using a variety of manufacturing techniques, such as forging, casting, milling, electro-chemical machining, electric-discharge machining, and the like. As such, the compressor component may have a series of manufacturing tolerances for the position, profile, twist, and chord that can cause the compressor component to vary from the nominal 3D shape defined by the coordinate values set forth in Table 1. This manufacturing tolerance may be, for example, +/−0.120 inches in a direction away from any of the coordinate values of Table 1 without departing from the scope of the subject matter described herein. In other aspects, the manufacturing tolerances may be +/−0.080 inches. In still other aspects, the manufacturing tolerances may be +/−0.020 inches.

In addition to manufacturing tolerances affecting the overall size of the compressor component, it is also possible to scale the airfoil to a larger or smaller airfoil size. In order to maintain the benefits of this 3D shape, in terms of stiffness and stress, it is necessary to scale the compressor component uniformly in the X, Y, and Z directions. However, since the Z values in Table 1 are measured from a centerline of the compressor rather than a point on the compressor component, the scaling of the Z values must be relative to the minimum Z value in Table 1. For example, the first (i.e., radially innermost) profile section is positioned approximately 23.819 inches from the compressor centerline and the second profile section is positioned approximately 25.152 inches from the engine centerline. Thus, if the compressor component was to be scaled 20% larger, each of the X and Y values in Table 1 may simply be multiplied by 1.2. However, each of the Z values must first be adjusted to a relative scale by subtracting the distance from the compressor centerline to the first profile section (e.g., the Z coordinates for the first profile section become Z=0, the Z coordinates for the second profile section become Z=1.333 inches, etc.). This adjustment creates a nominal Z value. After this adjustment, then the nominal Z values may be multiplied by the same constant or number as were the X and Y coordinates (1.2 in this example).

The Z values set forth in Table 1 may assume a compressor sized to operate at 60 Hz. In other aspects, the compressor component described herein may also be used in different size compressors (e.g., a compressor sized to operate at 50 Hz, etc.). In these aspects, the compressor component defined by the X, Y, and Z values set forth in Table 1 may still be used, however, the Z values would be offset to account for the radial spacing of the differently sized compressors and components thereof (e.g., rotors, discs, blades, casing, etc.). The Z values may be offset radially inwardly or radially outwardly, depending upon whether the compressor is smaller or larger than the compressor envisioned by Table 1. For example, the casing to which a vane is affixed may spaced farther from the compressor centerline (e.g., 20%) than that envisioned by Table 1. In such a case, the minimum Z values (i.e., the radially innermost profile section) would be offset a distance equal to the difference in casing size (e.g., the radially innermost profile section would be positioned approximately 28.583 inches from the engine centerline instead of 23.819 inches) and the remainder of the Z values would maintain their relative spacing to one another from Table 1 with the same scale factor as being applied to X and Y (e.g., if the scale factor is one then the second profile section would be positioned approximately 29.916 inches from the engine centerline—still 1.333 inches radially outward from the first profile section). Stated another way, the difference in spacing of the casing from the centerline would be added to all of the scaled Z values in Table 1.

Equation (1) provides another way to determine new Z values (e.g., scaled or translated) from the Z values listed in Table 1 when changing the relative size and/or position of the component defined by Table 1. In equation (1), Z₁ is the Z value from Table 1, Z_1min is the minimum Z value from Table 1, scale is the scaling factor, Z_2min is the minimum Z value of the component as scaled and/or translated, and Z₂ is the resultant Z value for the component as scaled and/or translated. Of note, when merely translating the component, the scaling factor in equation (1) is 1.00.
Z₂=[(Z₁−Z_1min)*scale+Z_2min]  (1)

In yet another aspect, the airfoil profile may be defined by a portion of the set of X, Y, and Z coordinate values set forth in Table 1 (e.g., at least 85% of said coordinate values).

Embodiment 1. A compressor component comprising a root portion, an airfoil portion extending from the root portion, the airfoil portion having an uncoated nominal profile substantially in accordance with Cartesian coordinate values of X, Y, and Z set forth in Table 1, wherein the X, Y, and Z coordinates are distances in inches measured in a Cartesian coordinate system, wherein, at each Z distance, the corresponding X and Y coordinates, when connected by a smooth continuous arc, define one of a plurality of airfoil profile sections, and wherein the plurality of airfoil profile sections, when joined together by smooth continuous arcs, form an airfoil shape.

Embodiment 2. The compressor component of embodiment 1, wherein the root portion and the airfoil portion form at least part of a compressor vane.

Embodiment 3. The compressor component of any of embodiments 1-2, wherein the root portion is configured to couple with a casing of a compressor.

Embodiment 4. The compressor component of any of embodiments 1-3, wherein the airfoil shape lies within an envelope of +/−0.120 inches measured in a direction normal to any of the plurality of airfoil profile sections.

Embodiment 5. The compressor component of any of embodiments 1-4, wherein the airfoil shape lies within an envelope of +/−0.080 inches measured in a direction normal to any of the plurality of airfoil profile sections.

Embodiment 6. The compressor component of any of embodiments 1-5, wherein the airfoil shape lies within an envelope of +/−0.020 inches measured in a direction normal to any of the plurality of airfoil profile sections.

Embodiment 7. The compressor component of any of embodiments 1-6, wherein the airfoil profile is in accordance with at least 85% of the X, Y, and Z coordinate values listed in Table 1.

Embodiment 8. The compressor component of any of embodiments 1-7, further comprising a coating applied to the airfoil shape, the coating having a thickness of less than or equal to 0.010 inches.

Embodiment 9. A compressor vane, comprising an airfoil portion having an uncoated nominal profile substantially in accordance with Cartesian coordinate values of X, Y, and Z set forth in Table 1, wherein the X, Y, and Z coordinate values are distances in inches measured in a Cartesian coordinate system, wherein, at each Z distance, the corresponding X and Y coordinates, when connected by a smooth continuous arc, define one of a plurality of airfoil profile sections, and wherein the plurality of airfoil profile sections, when joined together by smooth continuous arcs, define an airfoil shape.

Embodiment 10. The compressor vane of embodiment 9, wherein the X and Y coordinate values are scalable as a function of a same constant or number and a set of corresponding nominal Z coordinate values are scalable as a function of the same constant or number to provide at least one of a scaled up or a scaled down airfoil.

Embodiment 11. The compressor vane of any of embodiments 9-10, wherein the compressor vane is configured to couple with a plurality of compressor casings each spaced away from a compressor centerline by a different amount, wherein the Z coordinate values set forth in Table 1 are offset by a distance equal to the difference in radial spacing of each said compressor casing to provide at least one of a radially outwardly offset or radially inwardly offset airfoil shape.

Embodiment 12. The compressor vane of any of embodiments 9-11, wherein the airfoil shape lies within an envelope of +/−0.120 inches measured in a direction normal to any of the plurality of airfoil profile sections.

Embodiment 13. The compressor vane of any of embodiments 9-12, wherein the airfoil shape provides the compressor vane with a first bending natural frequency between 65 Hz and 110 Hz when scaled for use in a compressor with a 60 Hz rotation speed.

Embodiment 14. The compressor vane of any of embodiments 9-13, wherein the airfoil shape provides the compressor vane with a first bending natural frequency that differs by at least 5% from 1^st and 2^nd engine order excitations.

Embodiment 15. The compressor vane of any of embodiments 9-14, wherein the airfoil profile is in accordance with at least 85% of the X, Y, and Z coordinate values listed in Table 1.

Embodiment 16. The compressor vane of any of embodiments 9-16, further comprising a coating applied to the airfoil shape, the coating having a thickness of less than or equal to 0.010 inches.

Embodiment 17. A compressor, comprising a casing, a plurality of compressor vanes coupled to the casing, the plurality of compressor vanes circumferentially spaced around the casing and extending towards a center axis of the compressor, wherein each compressor vane of the plurality of compressor vanes has an airfoil comprising an airfoil portion having an uncoated nominal profile substantially in accordance with Cartesian coordinate values of X, Y, and Z set forth in Table 1, wherein the X, Y, and Z coordinate values are distances in inches measured in a Cartesian coordinate system, wherein, at each Z distance, the corresponding X and Y coordinates, when connected by a smooth continuous arc, define one of a plurality of airfoil profile sections, and wherein the plurality of airfoil profile sections, when joined together by smooth continuous arcs, define an airfoil shape.

Embodiment 18. The compressor of embodiment 17, wherein the casing and the plurality of compressor vanes coupled thereto comprise a compressor stage zero.

Embodiment 19. The compressor of any of embodiments 17-18, wherein the airfoil shape lies within an envelope of +/−0.120 inches measured in a direction normal to any of the plurality of airfoil profile sections.

Embodiment 20. The compressor of any of embodiments 17-19, wherein the airfoil profile is in accordance with at least 85% of the X, Y, and Z coordinate values listed in Table 1

Embodiment 21. An airfoil, comprising an airfoil profile substantially in accordance with the X, Y, and Z coordinates listed in Table 1, wherein the X, Y, and Z coordinates are distances in inches measured in a Cartesian coordinate system, wherein, at each Z distance, the corresponding X and Y coordinates, when connected by a smooth continuous arc, define one of a plurality of airfoil profile sections, and wherein the plurality of airfoil profile sections, when joined together by smooth continuous arcs, define an airfoil shape.

Embodiment 22. The airfoil of embodiment 21, wherein the airfoil is part of a vane of a gas turbine engine.

Embodiment 23. The airfoil of any of embodiments 21-22, wherein the vane is a compressor vane.

Embodiment 24. The airfoil of any of embodiments 21-23, wherein the airfoil shape lies within an envelope of +/−0.160 inches measured in a direction normal to any of the plurality of airfoil profile sections.

Embodiment 25. The airfoil of any of embodiments 21-24, wherein the airfoil shape lies within an envelope of +/−0.080 inches measured in a direction normal to any of the plurality of airfoil profile sections.

Embodiment 26. The airfoil of any of embodiments 21-25, wherein the airfoil shape lies within an envelope of +/−0.020 inches measured in a direction normal to any of the plurality of airfoil profile sections.

Embodiment 27. The airfoil of any of embodiments 21-26, wherein the airfoil profile is in accordance with at least 85% of the X, Y, and Z coordinates listed in Table 1.

Embodiment 28. The airfoil of any of embodiments 21-27 further comprising a coating.

Embodiment 29. A gas turbine engine vane, comprising an airfoil portion, comprising an airfoil profile substantially in accordance with the X, Y, and Z coordinates listed in Table 1, wherein the X, Y, and Z coordinates are distances in inches measured in a Cartesian coordinate system, wherein, at each Z distance, the corresponding X and Y coordinates, when connected by a smooth continuous arc, define one of a plurality of airfoil profile sections, and wherein the plurality of airfoil profile sections, when joined together by smooth continuous arcs, define an airfoil shape.

Embodiment 30. The gas turbine engine vane of embodiment 29, wherein the airfoil shape defines an airfoil portion of a compressor vane.

Embodiment 31. The gas turbine engine blade of any of embodiments 29-30, wherein the gas turbine engine vane is one of a plurality of gas turbine engine vanes that are assembled about an axis of a gas turbine to form an assembled gas turbine engine stage.

Embodiment 32. The gas turbine engine blade of any of embodiments 29-31, wherein the airfoil shape lies within an envelope of +/−0.160 inches measured in a direction normal to any of the plurality of airfoil profile sections.

Embodiment 33. The gas turbine engine blade of any of embodiments 29-32, wherein the airfoil shape lies within an envelope of +/−0.080 inches measured in a direction normal to any of the plurality of airfoil profile sections.

Embodiment 34. The gas turbine engine blade of any of embodiments 29-33, wherein the airfoil shape lies within an envelope of +/−0.020 inches measured in a direction normal to any of the plurality of airfoil profile sections.

Embodiment 35. The gas turbine engine blade of any of embodiments 29-34, wherein the airfoil profile is in accordance with at least 85% of the X, Y, and Z coordinates listed in Table 1.

Embodiment 36. The gas turbine engine vane of any of embodiments 29-35 further comprising a coating.

Embodiment 37. A gas turbine engine, comprising a plurality of gas turbine engine vanes circumferentially assembled about a center axis of the gas turbine engine, wherein at least one of the plurality of gas turbine engine vanes has an airfoil comprising an airfoil profile substantially in accordance with the X, Y, and Z coordinates listed in Table 1, wherein the X, Y, and Z coordinates are distances in inches measured in a Cartesian coordinate system, wherein, at each Z distance, the corresponding X and Y coordinates, when connected by a smooth continuous arc, define one of a plurality of airfoil profile sections, and wherein the plurality of airfoil profile sections, when joined together by smooth continuous arcs, define an airfoil shape.

Embodiment 38. The gas turbine engine of embodiment 37, wherein the plurality of gas turbine engine vanes form an assembled compressor stage.

Embodiment 39. The gas turbine engine of any of embodiments 37-38, wherein the airfoil shape lies within an envelope of +/−0.160 inches measured in a direction normal to any of the plurality of airfoil profile sections.

Embodiment 40. The gas turbine engine of any of embodiments 37-39, wherein the airfoil profile is in accordance with at least 85% of the X, Y, and Z coordinates listed in Table 1.

Embodiment 41. Any of the aforementioned embodiments 1-40, in any combination.

The subject matter of this disclosure has been described in relation to particular embodiments, which are intended in all respects to be illustrative rather than restrictive. Alternative embodiments will become apparent to those of ordinary skill in the art to which the present subject matter pertains without departing from the scope hereof. Different combinations of elements, as well as use of elements not shown, are also possible and contemplated.