Aerodynamic layout of open-rotor blades, open-rotor and engine thereof

Abstract

The application provides an open rotor blade aerodynamic layout structure, an open rotor and an engine, and relates to the field of open rotor engines.The aerodynamic layout structure comprises: a hub gap is arranged between a blade root and a hub, and the size of the hub gap is in the range of 1mm to 5mm.The shaft handle has a center line extending along its own axial direction, the blade root has a root profile, the root profile has a center point and a root chord length, the center point is located on the root chord length, the distance between the center line and the leading edge of the blade root in the direction of the root chord length is less than the distance between the center point and the leading edge of the blade root in the direction of the root chord length, and the distance between the center line and the center point in the direction of the root chord length is in the range of 20% to 65% of the root chord length.The hub profile of the hub comprises a non-axially symmetric end wall, and the blade root and the non-axially symmetric end wall are coupled to form a rotor flow channel, so that the root flow loss of the rotor blade is reduced, and the aerodynamic efficiency of the open fan is improved.

Description

Technical Field

[0001] This invention relates to the field of open rotor engines, and more particularly to the aerodynamic layout structure of open rotor blades, open rotors, and open rotor engines. Background Technology

[0002] Continuous advancements in aircraft propulsion system technology are essential for achieving energy conservation and emission reduction in the air transport industry. Improvements in aero-engine performance are achieved by increasing engine thermal efficiency and propulsive efficiency. Thermal efficiency is improved by increasing turbine inlet temperature, overall engine pressure ratio, and component efficiency; however, these three factors are already at relatively high levels, limiting further improvements. Propulsive efficiency is primarily improved by increasing the bypass ratio. However, for traditional turbofan engines, increasing the bypass ratio inevitably leads to an increase in nacelle diameter, resulting in increased weight and aerodynamic drag, thus limiting further increases in bypass ratio. In contrast, open rotor engines with a static-to-dynamic configuration, unaffected by nacelle installation effects, can achieve ultra-high bypass ratios (e.g., 30-90), significantly improving propulsive efficiency. Their fuel consumption can be reduced by 15%-20% or more compared to currently in-service advanced aero-engines.

[0003] The open fan is the core propulsion component of an open rotary engine, and its performance has a crucial impact on the engine's fuel consumption rate. In a rotary-stationary open fan configuration, the rotor blades need to adjust their pitch angle according to different operating conditions. Therefore, sufficient hub clearance must be maintained between the blade roots and the hub to ensure that the blades do not interfere with the hub when adjusting the pitch angle. However, a large hub clearance can lead to flow leakage at the blade roots. Simultaneously, leading-edge horseshoe vortices and corner vortices are generated in the tip region of the rotor blades, making the secondary flow at the blade roots more complex. Summary of the Invention

[0004] The purpose of this invention is at least to provide an aerodynamic layout structure for open rotor blades, an open rotor, and an open rotor engine, thereby reducing root flow losses of rotor blades and improving the aerodynamic efficiency of open fans.

[0005] The following provides a brief overview of one or more aspects to offer a basic understanding of them. This overview is not an exhaustive summary of all conceived aspects, nor is it intended to identify key or decisive elements of all aspects, nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form to prepare for the more detailed descriptions that follow.

[0006] One embodiment of the present invention provides an aerodynamic layout structure for an open rotor blade. The blade root is connected to a shaft, which is mounted on a hub. The aerodynamic layout structure includes: a hub gap between the blade root and the hub, the size of which is in the range of 1mm to 5mm, allowing the rotor blade to be adjusted within a pitch angle range of -10° to 90°. The shaft has a centerline extending along its own axial direction. The root profile of the blade root has a center point and a root chord length. The center point is located on the root chord length. The distance between the centerline and the leading edge of the blade root along the root chord length is less than the distance between the center point and the leading edge of the blade root along the root chord length. The distance between the centerline and the center point along the root chord length is in the range of 20% to 65% of the root chord length. The hub profile includes a non-axisymmetric endwall, and the blade root is coupled with the non-axisymmetric endwall to form a rotor flow channel.

[0007] In some embodiments, the non-axisymmetric end wall includes a first recess, which is located near the shaft shank, and the maximum radial height of the first recess does not exceed 6 mm.

[0008] In some embodiments, the circumferential width of the first recessed hub is not less than 1 / 3 of the grid pitch, where the grid pitch refers to the distance between adjacent rotor blades.

[0009] In some embodiments, the non-axisymmetric endwall includes a first recess and a second recess, the rotor blade includes a first rotor blade and a second rotor blade adjacent to the first rotor blade, the first recess is disposed near the shaft of the first rotor blade and the maximum radial height of the first recess does not exceed 6 mm, the second recess is disposed near the shaft of the second rotor blade and the maximum radial height of the second recess does not exceed 6 mm.

[0010] In some embodiments, the circumferential width of the hub of the first or second recess is not less than 1 / 3 of the grid pitch, wherein the grid pitch refers to the distance between adjacent rotor blades.

[0011] In some embodiments, the non-axisymmetric end wall includes a protrusion, and the hub profile between the first recess and the second recess is provided with the protrusion, the maximum radial height of the protrusion not exceeding 6 mm.

[0012] In some embodiments, the circumferential width of the raised hub is no greater than 1 / 3 of the grid pitch, where the grid pitch refers to the distance between adjacent rotor blades.

[0013] In some embodiments, the first recess, the second recess, or the protrusion extends along the flow control line, the flow control line coincides with the middle arc line of the rotor blade, and the angle between the portion of the flow control line extending beyond the leading edge of the rotor blade and the tangent of the middle arc line at the leading edge is in the range of -10° to 10°, and the angle between the portion of the flow control line extending beyond the trailing edge of the rotor blade and the tangent of the middle arc line at the trailing edge is in the range of -10° to 10°.

[0014] In some embodiments, the distance between the lowest point of the first recess and the highest point of the protrusion is different on different axial control lines of the hub profile, or the distance between the lowest point of the second recess and the highest point of the protrusion is different, wherein the axial control line is parallel to the axis of the open rotor.

[0015] In some embodiments, on the same axial control line of the hub profile, the first recess, the second recess, and the protrusion equally divide the distance between the first rotor blade and the second rotor blade on the axial control line, wherein the axial control line is parallel to the axial direction of the open rotor.

[0016] One embodiment of the present invention provides an open rotor, including open rotor blades, the open rotor blades including the aerodynamic layout structure of the above embodiment.

[0017] One embodiment of the present invention provides an open rotor engine, including the open rotor of the above embodiment.

[0018] This invention proposes an aerodynamic layout structure for open rotor blades, including an open fan rotor blade shank, hub clearance, and a non-axisymmetric endwall coupling design structure. By adjusting the relative position of the blade shank, controlling the size of the hub clearance, and applying the non-axisymmetric endwall on the hub profile, the airflow at the blade root can be effectively regulated. Through the mutual inhibition of the blade root leakage flow and the flow channel vortex, the radial flow at the blade root is weakened, the flow field structure is optimized, and the flow loss is reduced, thereby improving the aerodynamic efficiency of the blade. Attached Figure Description

[0019] The above-described features and advantages of the present invention will be better understood after reading the following detailed description of embodiments of the present disclosure in conjunction with the accompanying drawings. In the drawings, components are not necessarily drawn to scale, and components having similar related properties or features may have the same or similar reference numerals. Wherein:

[0020] Figure 1 This is a structural schematic diagram of an open fan component according to some embodiments;

[0021] Figure 2 This is a schematic diagram of the rotor blade structure based on some embodiments;

[0022] Figure 3 This is a schematic cross-sectional view of the non-axisymmetric end wall on the hub, as shown in some embodiments;

[0023] Figure 4 This is a schematic diagram of optimized control of the non-axisymmetric end wall on the hub, based on some embodiments;

[0024] Figure 5It is a simulation diagram of rotor blades and non-axisymmetric end walls based on some embodiments;

[0025] Figure 6 It is a diagram of the limiting streamlines between the existing open rotor blades and the hub profile;

[0026] Figure 7 It is a limit streamline diagram between the rotor blade and the hub profile after the rotor blade is coupled with the non-axisymmetric end wall, according to some embodiments. Detailed Implementation

[0027] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. It should be noted that the aspects described below with reference to the accompanying drawings and specific embodiments are merely exemplary and should not be construed as limiting the scope of protection of the present invention in any way.

[0028] It should be understood that the terms “system,” “device,” “unit,” and / or “module” used herein are a method of distinguishing different components, elements, parts, sections, or assemblies at different levels. However, if other words can achieve the same purpose, they may be replaced by other expressions.

[0029] It is understood that the technical terms that may be used in the description of this specification, such as “center,” “longitudinal,” “lateral,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” and “outer,” indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the implementation method and do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of the invention.

[0030] It should be noted that the use of terms such as "first" and "second" to define features in this document is merely for the purpose of distinguishing the corresponding features. Unless otherwise stated, these terms have no special meaning and should not be construed as limiting the scope of protection of this invention. As shown in this specification and claims, the terms "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural, unless the context clearly indicates otherwise. Generally, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, and these steps and elements do not constitute an exclusive list; the method or apparatus may also include other steps or elements.

[0031] In the description of this specification, it should also be noted that, unless otherwise expressly specified or limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, an integral connection, or a detachable connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium, or a connection within two components, etc. Those skilled in the art can understand the specific meaning of the above terms in this specification according to the specific circumstances.

[0032] The open fan is the core propulsion component of an open rotary engine, and its performance has a crucial impact on the engine's fuel consumption rate. For example... Figure 1 As shown, the open fan with a rotor-stationary configuration includes rotor blades 11 and stator blades 12, which are arranged in separate rows. This specification provides an aerodynamic layout structure for open rotor blades that improves gas flow through the rotor blades 11, thereby enhancing the aerodynamic efficiency of the open fan.

[0033] The blade root (referred to as blade root) of rotor blade 11 is connected to shaft 13, which is mounted on hub 14. Rotor blade 11 can be driven by a pitch mechanism (not shown) to adjust the pitch angle according to different operating conditions. Sufficient hub clearance must be maintained between the blade root of rotor blade 11 and hub 14 to ensure that the rotor blade 11 does not interfere with the hub when adjusting the pitch angle. However, a large hub clearance can lead to leakage flow at the blade root. Simultaneously, leading-edge horseshoe vortices and corner vortices will be generated in the end region of the rotor blades, making the secondary flow at the rotor blade root more complex. Therefore, a reasonable hub clearance dimension needs to be designed.

[0034] like Figure 2 As shown, the hub clearance 15 between the blade root and the hub 14 is in the range of 1mm to 5mm, allowing the rotor blade 11 to be adjusted over a wide range of pitch angles from -10° to 90°, effectively preventing interference between the rotor blade 11 and the hub 14 during adjustment. The hub clearance 15 between the blade root and the hub 14 is determined based on the hub profile of the hub 14. When the hub profile is flat, the hub clearance 15 can take a smaller value within the range of 1mm to 5mm, for example, 2mm. When the hub profile has large undulations, the hub clearance 15 can take a larger value within the range of 1mm to 5mm, for example, 4mm.

[0035] See also Figure 2The shaft shank 13 has a centerline 131 extending along its own axial direction. A center point and a root chord length are located on the root profile of the blade root, which refers to the distance between the leading edge 111 and the trailing edge 112 of the blade on the root profile. The center point is located on the root chord length. The distance between the centerline 131 and the leading edge 111 of the blade root along the root chord length is less than the distance between the center point and the leading edge 111 of the blade root along the root chord length. This means that the shaft shank 13 is positioned relatively close to the leading edge 111, which is beneficial for reducing the load on the pitch mechanism carrying the rotor blade 11. However, the close proximity of the shaft shank 13 to the leading edge 111 makes the leakage flow at the trailing edge of the rotor blade 11 more turbulent. Therefore, while the shaft shank 13 is positioned relatively close to the leading edge 111 of the rotor blade 11, the distance between the centerline 131 and the center point in the root chord direction is limited to a range of 10% to 30% of the root chord length (which can be 15% to 30% or 17.5% to 30% of the root chord length). This reduces the load on the pitch mechanism carrying the rotor blade 11 while minimizing leakage flow at the trailing edge of the rotor blade 11. In some embodiments, when improving leakage flow at the trailing edge of the rotor blade 11 is of higher priority, the shaft shank 13 may be positioned close to the leading edge 111 or trailing edge 112 of the rotor blade 11, but the distance between the centerline 131 and the center point in the root chord direction is still limited to a range of 10% to 30% of the root chord length.

[0036] In some embodiments, the hub profile of the hub 14 includes a non-axisymmetric endwall, which is located near the blade root. The blade root and the non-axisymmetric endwall are coupled to form a rotor flow channel. The non-axisymmetric endwall optimizes the airflow distribution of the rotor blade 11, reduces secondary flow losses, and improves the aerodynamic efficiency of the rotor blade 11 and even the open fan.

[0037] Figure 3 This is a schematic cross-sectional view of the non-axisymmetric end wall on the hub, as shown in some embodiments.

[0038] In some embodiments, such as Figure 3 As shown, the non-axisymmetric end wall includes a first recess 141, which is located near the shaft shank 13. In some embodiments, the maximum radial height R1 of the first recess 141 does not exceed 6 mm to avoid interference between the first recess 141 and parts below the hub 14. In some embodiments, the hub circumferential width L1 of the first recess 141 is not less than 1 / 3 of the grid pitch, where the grid pitch refers to the distance between adjacent rotor blades 11, or the distance between the leading edges of adjacent rotor blades 11. The radial direction referred to in this specification refers to the radial direction of the open rotor or the engine. The circumferential direction referred to in this specification refers to the direction around the axial direction of the open rotor or the engine.

[0039] In some embodiments, the non-axisymmetric endwall includes a second recess 142, and the rotor blade includes a first rotor blade and a second rotor blade adjacent to the first rotor blade. The first recess 141 is disposed near the shaft shank 13 of the first rotor blade, and the second recess 142 is disposed near the shaft shank 13 of the second rotor blade. In some embodiments, the maximum radial height R1 of the second recess 142 does not exceed 6 mm to avoid interference between the first recess 141 and the parts below the hub 14. In some embodiments, the hub circumferential width L2 of the second recess 142 is not less than 1 / 3 of the grid pitch.

[0040] In some embodiments, the non-axisymmetric endwall includes a protrusion 143. The protrusion 143 is provided on the hub profile between the first recess 141 and the second recess 142. To control the direction of the flow channel vortex, the maximum radial height R2 of the protrusion 143 does not exceed 6 mm. In some embodiments, the circumferential width of the protrusion 143 in the hub is not greater than 1 / 3 of the grid pitch.

[0041] Figure 4 This is a schematic diagram of optimized control of the non-axisymmetric end wall on the hub, based on some embodiments.

[0042] In some embodiments, such as Figure 4 As shown, on the hub profile, the first recess 141, the second recess 142, and the protrusion 143 all extend along the flow control line 41. The flow control line 41 coincides with the mid-arc line of the rotor blade 11, which is the line connecting the centers of the inscribed circles in the blade section. The angle between the portion of the flow control line 41 extending beyond the leading edge 111 of the rotor blade and the tangent of the mid-arc line at the leading edge 111 is in the range of -10° to 10°. The angle between the portion of the flow control line 41 extending beyond the trailing edge 112 of the rotor blade and the tangent of the mid-arc line at the trailing edge 112 is also in the range of -10° to 10°.

[0043] In some embodiments, due to the distribution of flow channels on the hub profile, the axial distances between adjacent rotor blades 11 are different. On different axial control lines 42 of the hub profile, the distances between the lowest point (also called the valley point) of the first recess 141 and the highest point (also called the peak point) of the protrusion 143 are different, and the distances between the lowest point (also called the valley point) of the second recess 142 and the highest point of the protrusion 143 are also different. For example, the distance between the lowest point of the first recess 141, the lowest point of the second recess 142, and the highest point of the protrusion 143 on the axial control line 42 near the leading edge 111 is greater than the distance between the lowest point of the first recess 141, the lowest point of the second recess 142, and the highest point of the protrusion 143 on the axial control line 42 near the trailing edge 112.

[0044] However, in some embodiments, on different axial control lines 42 of the hub profile, the ratio of the hub circumferential width of the first recess 141, the protrusion 143, and the second recess 142 to the axial distance between adjacent rotor blades 11 at the corresponding locations is approximately the same. In some embodiments, on the same axial control line 42 of the hub profile, the first recess 141, the second recess 142, and the protrusion 143 approximately equally divide the distance between the first rotor blade and the second rotor blade on the axial control line.

[0045] By controlling the direction of the first recess 141, the second recess 142, and the protrusion 143 on the hub profile through the flow control line 41 and the axial control line 42, the secondary flow field at the blade root is regulated, the hub clearance leakage flow is controlled, and the root leakage flow and secondary flow are mutually suppressed to reduce flow loss.

[0046] Based on the above embodiments, the aerodynamic layout structure, including the position of the shaft 13, the hub clearance 15, and the non-axisymmetric endwall, can achieve the following: Figure 5 The diagram shows a simulation of the rotor blades and the non-axisymmetric endwalls.

[0047] Figure 6 This is a diagram showing the limiting streamlines between the existing open rotor blades and the hub profile. Figure 7 This is a limit streamline diagram between the rotor blades and the hub profile after coupling the rotor blades with the non-axisymmetric endwall, as shown in some embodiments. Before performing aerodynamic layout optimization design for the coupling of the rotor blades with the non-axisymmetric endwall, such as... Figure 6 As shown, the suction surface of the blade exhibits strong radial flow, and the vortex at the blade root is significant, which reduces the work capacity at the blade root and increases flow losses. However, after optimizing the aerodynamic layout by coupling the rotor blades with the non-axisymmetric endwall, as shown... Figure 7 As shown, the radial flow on the suction surface of the blade is significantly reduced, the vortex ridges of the flow channel between adjacent rotor blades are closer to the blades, the vortex at the blade root is also weakened, the flow field is improved, the flow loss of the rotor blades is reduced, and the aerodynamic efficiency of the blades is improved.

[0048] The basic concepts have been described above. It is clear that the detailed disclosure above is merely illustrative and does not constitute a limitation of this specification, especially for those skilled in the art. Furthermore, unless expressly stated in the claims, the order of elements and sequences, the use of numbers and letters, or other names in this specification are not intended to limit the order of the processes and methods described herein. Although various examples of currently considered useful embodiments of the invention have been discussed in the foregoing disclosure, it should be understood that such details are for illustrative purposes only, and the appended claims are not limited to the disclosed embodiments. Rather, the claims are intended to cover all modifications and equivalent combinations that conform to the substance and scope of the embodiments described herein.

Claims

1. An aerodynamic layout structure for open rotor blades, wherein the root of the rotor blade is connected to a shaft, and the shaft is mounted on a hub, characterized in that, The aerodynamic layout structure includes: A hub gap is provided between the blade root and the hub, and the size of the hub gap is in the range of 1mm to 5mm, so that the rotor blade can be adjusted within the range of -10° to 90° of the blade pitch angle. The shaft has a centerline extending along its own axial direction, the root profile of the blade root has a center point, the root profile has a root chord length, the center point is located on the root chord length, the distance between the centerline and the leading edge of the blade root along the root chord length is less than the distance between the center point and the leading edge of the blade root along the root chord length, and the distance between the centerline and the center point along the root chord length is within the range of 20% to 65% of the root chord length; The hub profile includes a non-axisymmetric endwall, and the blade root is coupled to the non-axisymmetric endwall to form a rotor flow channel.

2. The aerodynamic layout structure of the open rotor blades according to claim 1, characterized in that, The non-axisymmetric end wall includes a first recess, which is located close to the shaft, and the maximum radial height of the first recess does not exceed 6 mm.

3. The aerodynamic layout structure of the open rotor blades according to claim 2, characterized in that, The circumferential width of the first recessed hub is not less than 1 / 3 of the grid pitch, wherein the grid pitch refers to the distance between adjacent rotor blades.

4. The aerodynamic layout structure of the open rotor blades according to claim 1, characterized in that, The non-axisymmetric end wall includes a first recess and a second recess. The rotor blade includes a first rotor blade and a second rotor blade adjacent to the first rotor blade. The first recess is located near the shaft of the first rotor blade, and the maximum radial height of the first recess does not exceed 6 mm. The second recess is located near the shaft of the second rotor blade, and the maximum radial height of the second recess does not exceed 6 mm.

5. The aerodynamic layout structure of the open rotor blades according to claim 4, characterized in that, The circumferential width of the hub of the first or second recess is not less than 1 / 3 of the grid pitch, wherein the grid pitch refers to the spacing between adjacent rotor blades.

6. The aerodynamic layout structure of the open rotor blades according to claim 4, characterized in that, The non-axisymmetric end wall includes a protrusion, and the hub profile between the first recess and the second recess is provided with the protrusion, the maximum radial height of the protrusion not exceeding 6 mm.

7. The aerodynamic layout structure of the open rotor blades according to claim 6, characterized in that, The circumferential width of the raised hub is no greater than 1 / 3 of the grid pitch, wherein the grid pitch refers to the distance between adjacent rotor blades.

8. The aerodynamic layout structure of the open rotor blades according to claim 6, characterized in that, The first depression, the second depression, or the protrusion extends along the flow control line, which coincides with the middle arc line of the rotor blade. The angle between the portion of the flow control line extending beyond the leading edge of the rotor blade and the tangent of the middle arc line at the leading edge is in the range of -10° to 10°. The angle between the portion of the flow control line extending beyond the trailing edge of the rotor blade and the tangent of the middle arc line at the trailing edge is in the range of -10° to 10°.

9. The aerodynamic layout structure of the open rotor blades according to claim 6, characterized in that, On different axial control lines of the hub profile, the distance between the lowest point of the first recess and the highest point of the protrusion is different, or the distance between the lowest point of the second recess and the highest point of the protrusion is different, wherein the axial control line is parallel to the axis of the open rotor.

10. The aerodynamic layout structure of the open rotor blades according to claim 6, characterized in that, On the same axial control line of the hub profile, the first recess, the second recess, and the protrusion equally divide the distance between the first rotor blade and the second rotor blade on the axial control line, wherein the axial control line is parallel to the axis of the open rotor.

11. An open rotor, comprising open rotor blades, characterized in that, The open rotor blades include the aerodynamic layout structure as described in any one of claims 1 to 10.

12. An open rotary engine, characterized in that, Including the open rotor as described in claim 11.

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