Pneumatic layout structure of open type rotor blade, open type rotor and engine of open type rotor

Abstract

The invention provides a pneumatic layout structure of open type rotor blades, an open type rotor and an engine of the open type rotor, and relates to the field of open type rotor engines. According to the pneumatic layout structure, a hub gap is formed between the root of the blade and the hub, and the size of the hub gap ranges from 1 mm to 5 mm. The shaft handle is provided with a center line extending in the axial direction of the shaft handle, the root molded surface of the blade root is provided with a center point, the root molded surface is provided with a root chord length, and the center point is located on the root chord length. The distance between the center line and the front edge of the blade root in the chord length direction of the root is smaller than the distance between the center point and the front edge of the blade root in the chord length direction of the root, and the distance between the center line and the center point in the chord length direction of the root ranges from 20% to 65% of the chord length of the root. The hub profile of the hub comprises the non-axisymmetric end wall, the blade root is coupled with the non-axisymmetric end wall to form a rotor flow channel, the root flow loss of the rotor blade is reduced, and the aerodynamic efficiency of the open fan is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of open rotor engine, in particular to the aerodynamic layout structure of open rotor blade, open rotor and open rotor engine. BACKGROUND

[0002] The continuous progress of aircraft propulsion system technology is the necessary guarantee to realize the energy saving and emission reduction of aviation transportation industry. The performance improvement of the aircraft engine is realized by improving the engine thermal efficiency and propulsion efficiency. The technical approach to improve the thermal efficiency is to increase the turbine inlet temperature and the total pressure ratio of the engine cycle and the component efficiency, but at present, these three factors are at a relatively high level, which leads to limited space for improving the thermal efficiency. The improvement of propulsion efficiency is mainly through increasing the bypass ratio, but for the traditional turbofan engine, the increase of the bypass ratio will inevitably lead to the increase of the diameter of the nacelle, and further lead to the increase of its weight and aerodynamic drag, which restricts the further increase of the bypass ratio. The open rotor engine with rotating and stationary configuration can realize super large bypass ratio (for example, 30~90) and greatly improve the propulsion efficiency, and its specific fuel consumption can be reduced by more than 15%~20% compared with the currently in-service advanced aircraft engine.

[0003] The open fan is the core propulsion component of the open rotor engine, and the performance of the open fan has a crucial influence on the specific fuel consumption of the open rotor engine. The rotor blades of the open fan with rotating and stationary configuration need to adjust the pitch angle according to different working conditions, therefore, a sufficient hub gap needs to be reserved between the blade root and the hub to ensure that the blade will not interfere with the hub when adjusting the pitch angle, but the larger hub gap will lead to the leakage flow of the blade root gap. At the same time, the end region of the rotor blade will produce leading edge horseshoe vortex, corner vortex and other vortices, making the secondary flow of the rotor blade root more complex. SUMMARY

[0004] The present application at least aims to provide an aerodynamic layout structure of open rotor blade, open rotor and open rotor engine, which reduces the flow loss of the root of the rotor blade and improves the aerodynamic efficiency of the open fan.

[0005] The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

[0006] One embodiment of the present invention provides an aerodynamic layout structure for an open rotor blade. The blade root of the rotor blade is connected to a shaft, which is mounted on a hub. The aerodynamic layout structure includes: a hub clearance between the blade root and the hub, with the clearance ranging from 1 mm to 5 mm, enabling 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 includes a center point, which 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 shorter 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 within a range of 20% to 65% of the root chord length. The hub profile of the hub includes a non-axisymmetric endwall, and the blade root and the non-axisymmetric endwall are coupled to form a rotor flow channel.

[0007] In some embodiments, the non-axisymmetric end wall includes a first recess, the first recess is disposed close to the shaft stem, and the maximum radial height of the first recess does not exceed 6 mm.

[0008] In some embodiments, the hub circumferential width of the first recess is no less than 1 / 3 of the pitch, where the pitch refers to the distance between adjacent rotor blades.

[0009] In some embodiments, 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 arranged near the shaft handle of the first rotor blade, and the maximum radial height of the first recess does not exceed 6 mm, the second recess is arranged near the shaft handle of the second rotor blade, and the maximum radial height of the second recess does not exceed 6 mm.

[0010] In some embodiments, the hub circumferential width of the first recess or the second recess is not less than 1 / 3 of the pitch, where the 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, and the maximum radial height of the protrusion does not exceed 6 mm.

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

[0013] In some embodiments, the first depression, the second depression or the protrusion extends and is distributed along the flow control line, the flow control line coincides with the center arc line of the rotor blade on the rotor blade, and the angle between the portion of the flow control line exceeding the leading edge of the rotor blade and the tangent of the center 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 exceeding the trailing edge of the rotor blade and the tangent of the center 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, or the distance between the lowest point of the second recess and the highest point of the protrusion, is different on different axial control lines of the hub profile, wherein the axial control lines are parallel to the axial direction of the open rotor.

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

[0016] One of the embodiments of the present application provides an open rotor, comprising an open rotor blade, which comprises the aerodynamic layout structure of the above-mentioned embodiments.

[0017] One of the embodiments of the present application provides an open rotor engine, comprising the open rotor of the above-mentioned embodiments.

[0018] The present application provides an aerodynamic layout structure of an open rotor blade, comprising an open fan rotor blade shaft handle, a hub gap and a non-axially symmetric end wall coupling design structure. By adjusting the relative position of the blade shaft handle, controlling the size of the hub gap and applying the non-axially symmetric end wall on the hub profile, the blade root airflow can be effectively regulated. By the mutual inhibition of the blade root leakage flow and the flow passage vortex, the blade root radial flow is weakened, the flow field structure is optimized, and the flow loss is reduced, so as to improve the aerodynamic efficiency of the blade. BRIEF DESCRIPTION OF DRAWINGS

[0019] The above features and advantages of the present application can be better understood after reading the detailed description of embodiments of the present application in conjunction with the following drawings. In the drawings, components are not necessarily drawn to scale and components having similar related properties or features can have the same or similar reference numerals. Among them: Figure 1 is a structural schematic diagram of an open fan component according to some embodiments; Figure 2 is a structural schematic diagram of a rotor blade according to some embodiments; Figure 3 is a sectional schematic diagram of a non-axially symmetric end wall on a hub according to some embodiments; Figure 4 is an optimized control schematic diagram of a non-axially symmetric end wall on a hub according to some embodiments; Figure 5 is a simulation diagram of a rotor blade and a non-axially symmetric end wall according to some embodiments; Figure 6 is a limit streamline diagram between an existing open rotor blade and a hub profile; Figure 7 is a plot of limiting streamlines between the rotor blade and the hub profile after coupling the rotor blade with the non-axisymmetric endwall according to some embodiments. DETAILED DESCRIPTION

[0020] The present application is described in detail below with reference to the attached drawing figures and specific embodiments. It should be noted that the aspects described below with reference to the drawing figures and specific embodiments are merely exemplary and should not be considered limiting in any way.

[0021] It should be understood that the terms "system," "device," "unit," and / or "module" as used herein are a method for distinguishing different components, elements, parts, sections, or assemblies from one another. However, the terms can be replaced by other expressions as long as the same meaning is conveyed.

[0022] It can be understood that the technical terms involved in the description of the specification, such as "center", "longitudinal", "transverse", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments, and do not indicate or imply that the device or element referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the scope of protection of the invention.

[0023] It should be noted that the terms "first", "second", and the like used herein to define features are merely used to distinguish the corresponding features for convenience, and the above terms have no special meaning unless otherwise stated. Therefore, they cannot be understood as limiting the scope of protection of the invention. As shown in the specification and claims, the terms "a", "one", "kind", and / or "the" do not refer to a single number, but also include plural numbers, unless the context clearly indicates otherwise. In general, the terms "include" and "contain" only indicate the inclusion of the steps and elements explicitly identified, and these steps and elements do not constitute an exclusive list, and the method or device can also include other steps or elements.

[0024] In the description of the specification, it should also be noted that, unless otherwise explicitly specified or limited, the terms "mount", "connect", "connect" should be understood broadly, for example, it can be a fixed connection, it can be integrally connected, or it can be detachably connected; it can be a mechanical connection, or it can be an electrical connection; it can be directly connected, or it can be indirectly connected through an intermediate medium, or the connection between two elements inside, etc. For those skilled in the art, the specific meaning of the above terms in the specification can be understood according to the specific circumstances.

[0025] The open fan is the core propulsion component of the open rotor engine, and its performance has a crucial impact on the specific fuel consumption of the open rotor engine. As shown in Figure 1 The open fan of the rotating and stationary configuration includes rotor blades 11 and stator blades 12, which are distributed in rows. The embodiments of the present specification provide an aerodynamic layout structure of the open rotor blade, which improves the gas flow of the rotor blade 11 to improve the aerodynamic efficiency of the open fan.

[0026] The blade root of the rotor blade 11 (which can be referred to as the blade root) is connected to the shaft handle 13, and the shaft handle 13 is installed on the hub 14. The rotor blade 11 can be driven by a variable pitch mechanism (not shown in the figure) to adjust the pitch angle according to different working conditions. A sufficient hub gap is required between the blade root of the rotor blade 11 and the hub 14 to ensure that the rotor blade 11 does not interfere with the hub when adjusting the pitch angle, but a larger hub gap will cause blade root gap leakage flow. At the same time, the end region of the rotor blade will generate leading edge horseshoe vortex, corner vortex, etc., making the secondary flow of the rotor blade root more complex. Therefore, it is necessary to design a reasonable hub gap size.

[0027] As shown in Figure 2 The size of the hub gap 15 between the blade root and the hub 14 is in the range of 1mm~5mm, so that the rotor blade 11 can be adjusted in a large range of -10°~90° pitch angle, effectively avoiding the interference between the rotor blade 11 and the hub 14 during adjustment. The hub gap 15 between the blade root and the hub 14 determines a reasonable hub gap 15 size according to the hub profile of the hub 14. When the hub profile is flat, the hub gap 15 can take a smaller value in the range of 1mm~5mm, for example, 2mm. When the hub profile fluctuates greatly, the hub gap 15 can take a larger value in the range of 1mm~5mm, for example, 4mm.

[0028] Referring to Figure 2, the shaft handle 13 has a center line 131 extending along its own axial direction. The root profile of the blade root has a center point, and the root profile has a root chord length. The root chord length refers to the distance between the leading edge 111 of the blade and the trailing edge 112 of the blade on the root profile. The center point is located on the root chord length, and the distance between the center line 131 and the leading edge 111 of the blade root along the root chord length is smaller than the distance between the center point and the leading edge 111 of the blade root along the root chord length, which means that the shaft handle 13 is relatively close to the leading edge 111, which is beneficial for reducing the load on the pitch mechanism that supports the rotor blade 11. However, if the shaft handle 13 is close to the leading edge 111, the leakage flow at the trailing edge of the blade root of the rotor blade 11 will be 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 within a range of 10% to 30% of the root chord length (which may be within a range of 15% to 30% of the root chord length or 17.5% to 30% of the root chord length). This reduces the load on the pitch mechanism of the rotor blade 11 while minimizing leakage flow at the root trailing edge of the rotor blade 11. In some embodiments, when improving leakage flow at the root trailing edge of the rotor blade 11 is a higher priority, the shaft shank 13 may be positioned close to the leading edge 111 or the 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 within a range of 10% to 30% of the root chord length.

[0029] In some embodiments, the hub profile of hub 14 includes a non-axisymmetric end wall located near the blade root. The blade root and the non-axisymmetric end wall are coupled to form a rotor flow channel. The provision of the non-axisymmetric end wall can optimize the airflow distribution of rotor blades 11, reduce secondary flow losses, and improve the aerodynamic efficiency of rotor blades 11 and, consequently, the open fan.

[0030] Figure 3 is a schematic cross-sectional view of a non-axisymmetric end wall on a hub according to some embodiments.

[0031] In some embodiments, as Figure 3 As shown, the non-axisymmetric end wall includes a first recess 141, which is located near the shaft 13. In some embodiments, the maximum radial height R1 of the first recess 141 does not exceed 6 mm to prevent 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 no less than 1 / 3 of the pitch, where the pitch refers to the spacing between adjacent rotor blades 11, or the spacing between the leading edges of adjacent rotor blades 11. The radial direction described in this specification refers to the radial direction of an open rotor or an engine. The circumferential direction described in this specification refers to the direction around the axial direction of an open rotor or an engine.

[0032] In some embodiments, the non-axisymmetric endwall includes a second recess 142, the rotor blades include a first rotor blade and a second rotor blade adjacent to the first rotor blade, the first recess 141 is disposed proximate to the shank 13 of the first rotor blade, and the second recess 142 is disposed proximate to the shank 13 of the second rotor blade. In some embodiments, the maximum radial height R1 of the second recess 142 is no more than 6mm 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 no less than 1 / 3 of the pitch.

[0033] In some embodiments, the non-axisymmetric endwall includes a protrusion 143 disposed on the hub profile between the first recess 141 and the second recess 142, the protrusion 143 has a maximum radial height R2 no more than 6mm to control the flow passage vortex trajectory. In some embodiments, the hub circumferential width of the protrusion 143 is no more than 1 / 3 of the pitch.

[0034] Figure 4 is a schematic diagram of the optimization control of the non-axisymmetric endwall on the hub according to some embodiments.

[0035] In some embodiments, as shown in Figure 4 the first recess 141, the second recess 142 and the protrusion 143 are all distributed along the flow control line 41 on the hub profile. The flow control line 41 coincides with the mean camber line of the rotor blade 11 on the rotor blade 11, and the mean camber line of the rotor blade 11 is the connecting line of the centers of the inscribed circles in the blade profile section. The angle between the part of the flow control line 41 beyond the leading edge 111 of the rotor blade 11 and the tangent of the mean camber line at the leading edge 111 is within the range of -10°~10°, and the angle between the part of the flow control line 41 beyond the trailing edge 112 of the rotor blade and the tangent of the mean camber line at the trailing edge 112 is within the range of -10°~10°.

[0036] In some embodiments, due to the distribution of the flow passage on the hub profile, the axial distance between the adjacent rotor blades 11 is different at different axial control lines 42 on the hub profile, the distance between the lowest point (also known as the valley point) of the first recess 141 and the highest point (also known as the peak point) of the protrusion 143, and the distance between the lowest point (also known as the valley point) of the second recess 142 and the highest point of the protrusion 143 are different at different axial control lines 42 on the hub profile. 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 is greater at the axial control line 42 close to the leading edge 111 than at the axial control line 42 close to the trailing edge 112.

[0037] 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 that location is substantially 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 substantially evenly divide the distance between the first rotor blade and the second rotor blade on the axial control line.

[0038] Through the flow control line 41 and the axial control line 42, the directions of the first recess 141, the second recess 142 and the protrusion 143 on the hub surface are controlled to regulate the secondary flow field at the root of the blade, control the hub gap leakage flow, achieve mutual suppression of the root leakage flow and the secondary flow, and reduce flow losses.

[0039] Based on the above embodiment, the aerodynamic layout structure such as the position of the shaft handle 13, the hub gap 15 and the non-axisymmetric end wall can be obtained as follows: Figure 5 A simulation of a rotor blade with a non-axisymmetric endwall is shown.

[0040] Figure 6 It is the limiting streamline diagram between the existing open rotor blades and the hub profile. Figure 7 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. Before the aerodynamic layout optimization design of the rotor blade coupled with the non-axisymmetric end wall is performed, as shown in FIG. Figure 6 As shown in Figure 1, the blade suction surface shows a strong radial flow, and the vortex at the blade root is obvious, which will reduce the work capacity of the blade root and increase the flow loss. After the aerodynamic layout optimization design of the rotor blade coupled with the non-axisymmetric end wall, as shown in Figure 1, the blade suction surface shows a strong radial flow, and the vortex at the blade root is obvious, which will reduce the work capacity of the blade root and increase the flow loss. Figure 7 As shown in the figure, the radial flow on the suction surface of the blade is significantly weakened, the vortex ridge lines of the flow channel between adjacent rotor blades are closer to the blades, the vortex at the root of the blade is also weakened, the flow field is improved, the flow loss of the rotor blade is reduced, and the aerodynamic efficiency of the blade is improved.

[0041] The basic concepts have been described above. Obviously, for those skilled in the art, the above detailed disclosure is only for example and does not constitute a limitation of this specification. In addition, unless expressly stated in the claims, the order of elements and sequences, the use of alphanumeric characters, or the use of other names in this specification are not intended to limit the order of the processes and methods in this specification. Although some embodiments of the invention currently considered useful are discussed through various examples in the above disclosure, it should be understood that such details are for illustrative purposes only, and the appended claims are not limited to the disclosed embodiments. On the contrary, the claims are intended to cover all modifications and equivalent combinations that are consistent with the essence and scope of the embodiments of this specification.

Claims

1. The aerodynamic layout structure of the open rotor blade, the blade root of the rotor blade is connected to the shaft, and the shaft is installed on the 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 1 mm to 5 mm, so that the rotor blade can be adjusted within a pitch angle range of -10° to 90°; The shank 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 in the root chord length direction is within a range of 20% to 65% of the root chord length; The hub profile of the hub includes a non-axisymmetric end wall, and the blade root is coupled with the non-axisymmetric end wall to form a rotor flow channel.

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

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

4. The aerodynamic layout structure of the open rotor blade 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 arranged close to the shaft handle of the first rotor blade, and the maximum radial height of the first recess does not exceed 6 mm, the second recess is arranged close to the shaft handle 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 blade according to claim 4, characterized in that: The hub circumferential width of the first recess or the second recess is not less than 1 / 3 of the pitch, wherein the pitch refers to the distance between adjacent rotor blades.

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

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

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

9. The aerodynamic layout structure of the open rotor blade 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 axial direction of the open rotor.

10. The aerodynamic layout structure of the open rotor blade 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 evenly 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.

11. An open rotor, comprising open rotor blades, characterized in that: The open rotor blade includes the aerodynamic layout structure according to any one of claims 1 to 10.

12. An open rotor engine, characterized in that Comprising the open rotor as claimed in claim 11.

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