A blade, blade assembly, turbomachinery, and method of blade shaping to inhibit leakage vortex breakdown

Abstract

The present disclosure provides a kind of blade for inhibiting the blade of leakage vortex break, blade assembly, impeller machinery and blade shaping method.The blade profile is defined according to the cross section profile of the height direction accumulation, the cross section profile has the ratio of the height of the cross section profile and the total height of the blade, the dimensionless blade height H=1 is the blade tip, the dimensionless blade height H=0 is the blade root;The cross section profile also has the back bending angle δ;At the dimensionless blade height H=1, the back bending angle δ=13 °, and has the tolerance range of the numerical ratio ±20%.

Description

Technical Field

[0001] This disclosure relates to the field of turbomachinery technology, and in particular to a blade, blade assembly, turbomachinery, and blade design method for suppressing leakage vortex breakage. Background Technology

[0002] When turbomachinery is operating, the pressure difference at the blade tip region causes some airflow to cross the tip gap, forming leakage flow and leakage vortices, resulting in tip leakage losses. Currently, methods to control tip leakage losses focus on rib tip optimization design, that is, adding rib structures at the blade tip to suppress airflow leakage.

[0003] Tip leakage loss includes losses within the clearance and mixing losses between the leakage flow outside the clearance and the mainstream flow. The mixing loss outside the clearance is not only proportional to the leakage flow rate (tip clearance) but also related to vortex breakup. Under conditions without vortex breakup, tip leakage loss increases approximately linearly with increasing tip clearance. Under conditions of vortex breakup, the variation of tip leakage loss with clearance exhibits a convex parabolic shape. Therefore, suppressing vortex breakup is a crucial aspect of controlling tip leakage loss, and effectively suppressing vortex breakup has become a pressing technical problem in this field.

[0004] It should be noted that the information disclosed in this background section is intended only to enhance the understanding of the technical background of this disclosure, and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] As stated above, the purpose of this disclosure is to provide a blade that suppresses the breakup of leakage vortices.

[0006] Another object of this disclosure is to provide a blade assembly.

[0007] Another object of this disclosure is to provide a turbomachinery.

[0008] Another objective of this disclosure is to provide a method for shaping blades.

[0009] The principle behind the improved technical effect achieved by this disclosure lies in the Hall vortex kernel equation:

[0010]

[0011] In the formula, s is the direction of the vortex core towards the flow, Γ is the circulation of the vortex, δ is the radius of the vortex core, and p is the static pressure of the flow field.

[0012] As can be seen from the above formula, the pressure gradient at the center of the vortex core (term A) consists of two parts: the pressure gradient of the main current within the channel (term B) and the pressure gradient formed by the circumferential circulation due to the vortex rotation.

[0013] (Option C); The reverse pressure gradient (Option B) within the blade passage is directly transmitted to the vortex core of the leakage vortex (Option A). Therefore, the existence of the mainstream reverse pressure gradient is detrimental to the stability of the leakage vortex, and the larger the reverse pressure gradient, the more detrimental it is to the stability of the leakage vortex. Simultaneously, since the rotation direction of the leakage vortex is the same as that of the turbine blades, the leakage vortex is also subjected to an outward Coriolis force, which is in the same direction as the centrifugal force generated by the rotation of the leakage vortex. This causes the radial positive pressure gradient required for the leakage vortex to maintain its structural stability to increase to a certain extent. Therefore, the Coriolis force experienced by the leakage vortex is also detrimental to its stability. Based on the above, the inventors, through in-depth research, proposed that by optimizing the design of the blade profile parameters, the above-mentioned Option B and Option C can be reduced, thereby reducing the pressure gradient (Option A) at the center of the vortex core of the leakage vortex, achieving the technical effect of improving the stability of the leakage vortex and suppressing the occurrence of leakage vortex breakage.

[0014] This disclosure discloses a blade for suppressing leakage vortex breakage, which is achieved by the following scheme: a blade whose blade shape is defined by a cross-sectional profile stacked along the height direction, the cross-sectional profile having a dimensionless blade height H, which is the ratio of the height of the cross-sectional profile to the total height of the blade, the dimensionless blade height H = 1 being the blade tip, and the dimensionless blade height H = 0 being the blade root; the cross-sectional profile also has a backbend angle δ; at the dimensionless blade height H = 1, the backbend angle δ = 13°, and has a tolerance range of ±20% of the numerical ratio.

[0015] By employing the small backbend angle design of the blade tip section, the curvature of the suction line of the blade cross-section profile increases in the front region of the throat and decreases in the rear region of the throat. This results in faster airflow acceleration in the front region of the suction surface throat and slower airflow acceleration in the rear region of the throat. Consequently, the difference between the peak Mach number at the throat position and the exit Mach number of the blade cascade is reduced, which helps to reduce the reverse pressure gradient in the rear region of the throat. This improves the stability of the leakage vortex, suppresses leakage vortex breakup, and reduces the blade tip leakage loss.

[0016] In one or more embodiments, the backbend angle δ is defined by the exit Mach number of the cascade composed of the plurality of blades, and satisfies the formula:

[0017] -20Ma exit +31.5≤δ≤-25Ma exit +39

[0018] In the formula, Ma exit The exit Mach number of the blade cascade; at the dimensionless blade height H = 1, the backbend angle δ takes its minimum value.

[0019] In one or more embodiments, the blade has an angle of attack α; at a dimensionless blade height H = 1, the angle of attack α is a positive angle of attack and is within the range of 0° to 5°.

[0020] In one or more embodiments, the cross-sectional profile has a leading-edge dimensionless diameter D; at a dimensionless blade height H = 1, the leading-edge dimensionless diameter D = 0.87, and has a tolerance range of ±20% of the numerical ratio.

[0021] In one or more embodiments, the cross-sectional profile has a leading edge construction angle β. 1k At the dimensionless leaf height H = 1, the leading edge construction angle β 1k =74.09°, and has a tolerance range of ±15% of the numerical ratio.

[0022] In one or more embodiments, the cross-sectional profile has an installation angle γ; at a dimensionless blade height H = 1, the installation angle γ = 34.76°, and has a tolerance range of ±5% of the numerical ratio.

[0023] In one or more embodiments, the blade includes a suction surface and a pressure surface; the suction surface has a suction side rib extending outward along the height direction at the blade tip, and the pressure surface has a pressure side rib extending outward along the height direction at the blade tip; the outer surface of the pressure side rib is recessed in the direction of the suction surface to form a concave surface, and the pressure side rib is inclined in the direction of the pressure surface to form an oblique rib.

[0024] According to another aspect of this disclosure, a blade assembly includes the blades described in the above embodiments.

[0025] According to another aspect of this disclosure, a turbomachinery includes the blades described in the above embodiments.

[0026] According to another aspect of this disclosure, a blade design method includes:

[0027] S1. Select a certain leaf shape as the benchmark leaf shape to be optimized;

[0028] S2. Perform blade profile parameter optimization design on the cross-sectional profile of the reference blade profile at the blade tip, and determine the distribution of the blade profile parameters in the height direction according to predetermined rules to obtain the optimized blade profile;

[0029] S3. Obtain the limited range of recirculation zone formed by the tip leakage vortex of the optimized blade, and determine whether the limited range of recirculation zone meets the predetermined characteristic conditions;

[0030] If not, then repeat steps S2 to S3;

[0031] If so, the design is complete. Attached Figure Description

[0032] The above and other features, properties, and advantages of this disclosure will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, in which the same reference numerals always denote the same features. It should be noted that these drawings are merely illustrative and are not drawn to scale, and should not be construed as limiting the scope of protection actually claimed by this disclosure, wherein:

[0033] Figure 1 This is a schematic diagram of the flow characteristics of a typical tip leakage flow.

[0034] Figure 2 This is a schematic diagram of the tip cross-sectional profile of a baseline airfoil and an optimized airfoil of an embodiment.

[0035] Figure 3 The diagram shows the dimensionless diameter distribution of the leading edge of a baseline airfoil and an optimized airfoil of an embodiment.

[0036] Figure 4 The diagram shows the leading edge construction angle distribution of a baseline airfoil and an optimized airfoil of an embodiment.

[0037] Figure 5 This is a diagram showing the installation angle distribution of a baseline airfoil and an optimized airfoil of an embodiment.

[0038] Figure 6A Simulation diagram of leakage vortex flow characteristics for a reference airfoil;

[0039] Figure 6B This is a simulation diagram of the leakage vortex flow characteristics of an optimized blade profile according to one embodiment.

[0040] Figure 7 This is a schematic diagram of a blade structure according to one embodiment.

[0041] Figure 8 This is a schematic diagram of a rib tip structure according to one embodiment.

[0042] Figure 9 The tip leakage flow distribution diagrams are obtained for a baseline airfoil and an optimized airfoil of an embodiment.

[0043] Figure 10 The diagram shows the tip leakage flow distribution obtained for a conventional rib tip structure and an embodiment of the rib tip structure.

[0044] Explanation of reference numerals in the attached figures:

[0045] 1. Leaf blade; 11. Leading edge; 12. Trailing edge; 13. Suction surface; 131. Suction lateral rib; 14. Pressure surface; 141. Pressure lateral rib; 142. Concave surface; 143. Oblique rib; 15. Leaf tip; 16. Leaf root;

[0046] 2. Cross-sectional profile; 21. Leading edge line; 22. Trailing edge line; 23. Suction line; 24. Pressure line;

[0047] 3. Palisade;

[0048] 4. Channel vortex;

[0049] 5. Leakage vortex;

[0050] 6. Limited reflux zone;

[0051] Z. Height direction; H'. Section profile height; H' max Total blade height. Detailed Implementation

[0052] Reference will now be made in detail to various embodiments of this disclosure, examples of which are shown in the accompanying drawings and described below. Although this disclosure will be described in conjunction with exemplary embodiments, it should be understood that it is not intended to limit this disclosure to those exemplary embodiments. Rather, this disclosure is intended to cover not only these exemplary embodiments, but also various alternatives, modifications, equivalents, and other embodiments that may be included within the spirit and scope of this disclosure as defined by the appended claims.

[0053] In the following description, the orientation or positional relationship indicated by terms such as "upper", "lower", "front", "back", "inner", "outer" or other directional terms is based on the orientation or positional relationship shown in the accompanying drawings and is only for the convenience and simplification of description, and is not intended to indicate or imply that the device or component referred to must have a specific orientation, be constructed and / or be implemented in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this disclosure.

[0054] This disclosure uses specific terms to describe embodiments, such as "an embodiment" and / or "one embodiment," referring to a particular feature, structure, or characteristic associated with at least one embodiment of this disclosure. Therefore, it should be emphasized and noted that "an embodiment" or "one embodiment" mentioned twice or more in different locations in this disclosure does not necessarily refer to the same embodiment. Furthermore, certain features, structures, or characteristics in one or more embodiments of this disclosure can be appropriately combined.

[0055] All terms used in this disclosure have the same meaning as understood by one of ordinary skill in the art to which this disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant art, and not as idealized or highly formalized meanings, unless expressly defined herein.

[0056] In this disclosure, "height direction" refers to the direction between the blade root and the blade tip, i.e., the Z-direction, and in blade assemblies and turbomachinery, it is also the radial direction relative to the axis of rotation.

[0057] refer to Figure 1 , Figure 2 , Figure 7 As shown, the blade shape is determined by a cross-sectional profile 2 stacked along the height direction Z. The cross-sectional profile 2 includes a leading edge line 21, a trailing edge line 22, a suction line 23, and a pressure line 24. The leading edge line 21, the trailing edge line 22, the suction line 23, and the pressure line 24 are stacked along the height direction Z to form the leading edge 11, trailing edge 12, suction surface 13, and pressure surface 14 of the blade 1, respectively. Multiple blades 1 can form a blade cascade 3. The leading edge line 21 is an inlet arc with a leading edge diameter D'. The trailing edge line 22 is an outlet arc. The maximum inscribed circle of the cross-sectional profile 2 defines the maximum thickness C of the cross-sectional profile 2. max The airflow channel formed by the blade cascade 3 composed of multiple blades 1 has a throat, and there is a throat point on the suction line 23 corresponding to one end of the throat; the cross-sectional profile 2 also includes a chord line, a middle arc line, and a frontal line; the middle arc line is the line connecting the centers of the inscribed circles of the cross-sectional profile 2 and has a leading edge point, and the leading edge point is the endpoint of the middle arc line in the direction of the leading edge 11; the frontal line is the line connecting the corresponding points of multiple cross-sectional profiles 2 in the blade cascade 3.

[0058] The dimensionless blade height H is the sum of the height H' of the cross-sectional profile 2 and the total height H' of the blade 1. max In the ratio, the dimensionless leaf height H=1 is the leaf tip 15, and the dimensionless leaf height H=0 is the leaf root 16.

[0059] The backbend angle δ is the acute angle between the tangent of the suction line 23 at the throat point and the tangent of the suction line 23 at the point where the suction line 23 and the trailing edge line 22 are tangent.

[0060] Leading edge construction angle β 1k Also known as the inlet construction angle, it is the angle between the tangent of the middle arc line at the leading edge point and the branch of the forehead line toward the pressure line 24.

[0061] The dimensionless leading edge diameter D is the sum of the leading edge diameter D' and the maximum thickness C. max The ratio.

[0062] The mounting angle γ is the acute angle between the forehead line and the chord line.

[0063] The angle of attack α is the leading edge construction angle β 1k The difference between the angle of attack and the inlet airflow angle of the blade cascade 3; 0 angle of attack indicates the leading edge configuration angle β. 1kConsistent with the direction of incoming flow, a positive angle of attack indicates that the airflow is directed toward the pressure surface 14, while a negative angle of attack indicates that the airflow is directed toward the suction surface 13.

[0064] As mentioned above, for reference Figure 1 The typical flow characteristics of tip leakage flow are shown. The leakage flow near the leading edge (i.e., roughly the front region of the throat) is entrained into channel vortex 4, and the leakage flow near the trailing edge (i.e., roughly the rear region of the throat) is entrained into leakage vortex 5. By optimizing the airfoil design with preferred airfoil parameters, the vortex breaking phenomenon of the leakage vortex 5 near the trailing edge can be suppressed, the tip leakage loss can be reduced, and the aerodynamic efficiency of the blade 1 can be improved.

[0065] Since the airfoil near the tip height has a more significant impact on the tip leakage flow and the leakage vortex 5, it is preferable to optimize the airfoil design of the cross-sectional profile 2 with the height position near the tip to improve the stability of the leakage vortex and suppress leakage vortex breakage.

[0066] The present disclosure discloses a blade 1 for suppressing leakage vortex breakage, wherein the cross-sectional profile 2 of the blade 1 has a backbend angle δ; at the dimensionless blade height H=1, the backbend angle δ=13° and has a tolerance range of ±20% of the numerical ratio.

[0067] See Figure 2 The magnitude of the backbend angle δ reflects the curvature change at the oblique cut of the suction line 23, and has a significant impact on the peak Mach number at the throat position. Reducing the backbend angle δ will increase the curvature of the suction line 23 in the region in front of the throat (throat point) and decrease the curvature in the region behind the throat. As a result, the airflow in the region in front of the throat on the suction surface 13 accelerates faster, while the airflow in the region behind the throat accelerates slower. This reduces the difference between the peak Mach number and the exit Mach number at the throat, thereby reducing the reverse pressure gradient in the region behind the throat and suppressing the backflow of the leakage vortex 5 core. Therefore, by adopting the small backbend angle design of the blade tip section, the region behind the throat of the suction surface 13 can have a smaller reverse pressure gradient, suppress leakage vortex breakup, reduce blade tip leakage loss, and improve the aerodynamic efficiency of the blade 1.

[0068] Optionally, the backbend angle δ varies continuously along the height direction Z, so that the cross-sectional profile 2 at different height positions can vary accordingly with the limitation of the small backbend angle design of the blade tip section, in order to meet design requirements including at least aerodynamic performance.

[0069] Furthermore, in one or more embodiments, the backbend angle δ is defined by the exit Mach number of the blade cascade 3 composed of the plurality of blades 1, and satisfies the formula:

[0070] -20Ma exit +31.5≤δ≤-25Ma exit +39

[0071] In the formula, Ma exit The Mach number at the blade cascade exit is δ; at the dimensionless blade height H = 1, the backbend angle δ is minimized; this design is particularly suitable for the aerodynamic performance requirements of the blade 1 when the blade cascade exit Mach number is preset in the range of 0.7 to 1.0.

[0072] In one or more embodiments, the blade 1 has the angle of attack α; at the dimensionless blade height H = 1, the angle of attack α is a positive angle of attack and satisfies the range of 0° to 5°.

[0073] The large angle of attack design increases the leakage of the channel vortex 4 and decreases the leakage of the leakage vortex 5. Furthermore, the increased flow rate of the channel vortex 4 can be effectively controlled through the rib tip structure design. Therefore, preferably, the large angle of attack design within the specified range reduces the flow rate of the leakage vortex 5, weakens its strength, improves its stability, and suppresses vortex breakage.

[0074] In one or more embodiments, the cross-sectional profile 2 has the dimensionless leading edge diameter D; at the dimensionless blade height H = 1, the dimensionless leading edge diameter D = 0.87, and has a tolerance range of ±20% of the numerical ratio.

[0075] The large leading edge diameter design of the blade tip section is beneficial to improving the angle of attack performance and avoiding flow separation under extreme conditions. At the same time, the value of the dimensionless leading edge diameter D is not too large, which can reduce the risk of a deceleration zone before the airflow accelerates to the throat and the flow separation at the suction surface 13, thus facilitating flow stability.

[0076] Optionally, the dimensionless leading edge diameter D varies continuously along the height direction Z, so that the cross-sectional profile 2 at different height positions can vary accordingly with the design limitations of the large leading edge diameter of the blade tip cross-section to meet design requirements.

[0077] In one or more embodiments, the cross-sectional profile 2 of the blade 1 has the leading edge construction angle β. 1k At the dimensionless leaf height H = 1, the leading edge construction angle β 1k =74.09°, with a numerical tolerance range of ±15%. This design achieves the design requirement of a positive angle of attack, which helps to improve the stability of the leakage vortex 5 and suppress vortex breakage.

[0078] Optionally, the leading edge construction angle β 1kThe profile 2 changes continuously along the height direction Z, so that the cross-sectional profile 2 at different height positions can change with the leading edge construction angle β of the blade tip cross-sectional profile 2. 1k的 The design is constrained and varied accordingly to meet design requirements.

[0079] In one or more embodiments, the cross-sectional profile 2 of the blade 1 has the mounting angle γ; at the dimensionless blade height H = 1, the mounting angle γ = 34.76°, and has a numerical scale.

[0080] Tolerance range of ±5%.

[0081] Changing the installation angle γ can affect the load distribution on the blade 1. Decreasing the installation angle γ shifts the load position forward, making the blade profile more forward-loaded. This reduces the lateral pressure gradient, vortex circulation, and Coriolis force in the region behind the throat. Therefore, adopting the small installation angle design at the blade tip section can improve the stability of the leakage vortex and suppress its breakup.

[0082] Optionally, the mounting angle γ varies continuously along the height direction Z, so that the cross-sectional profile 2 at different height positions can vary accordingly with the limitation of the small mounting angle design of the blade tip section to meet the design requirements.

[0083] Preferably, in one or more embodiments, the blade 1 is obtained by optimizing a design based on a reference airfoil, which has the backbend angle δ distribution shown in Table 1, and the backbend angle δ has a tolerance range of ±20% of the numerical proportion. This design can better meet other design requirements while suppressing leakage vortex breakup.

[0084] Table 1 shows the distribution of the backbend angle δ before and after the airfoil optimization design.

[0085] Dimensionless leaf height H The back bend angle δ (°) of the reference airfoil Optimize the backbend angle δ (°) of the blade profile. 0 19 19 0.5 18 18 1 16 13

[0086] Preferably, in one or more embodiments, the blade 1 is obtained by optimization design based on a reference airfoil, which has the leading edge construction angle β as shown in Table 2. 1k Distribution, and the leading edge construction angle β 1k It has a tolerance range of ±15% in numerical proportion. This design can better meet other design requirements while suppressing leakage vortex breakup.

[0087] Table 2 shows the leading edge construction angle β before and after the airfoil optimization design. 1k distributed

[0088]

[0089]

[0090] Preferably, in one or more embodiments, the blade 1 is obtained by optimizing an existing reference airfoil, which has the dimensionless leading-edge diameter D distribution shown in Table 3, and the dimensionless leading-edge diameter D has a tolerance range of ±20% of the numerical ratio. This design can better meet other design requirements while suppressing leakage vortex breakup.

[0091] Table 3 shows the distribution of the dimensionless leading edge diameter D before and after the airfoil optimization design.

[0092]

[0093] Preferably, in one or more embodiments, the blade 1 is obtained by optimizing an existing reference airfoil, which has the installation angle γ distribution shown in Table 4, and the installation angle γ has a tolerance range of ±5% of the numerical ratio. This design can better meet other design requirements while suppressing leakage vortex breakup.

[0094] Table 4 shows the distribution of the installation angle γ before and after the blade optimization design.

[0095] Dimensionless leaf height H Mounting angle (°) of the reference airfoil Optimize the installation angle (°) of the blade profile. 0.0 57.61 57.25 0.1 55.83 54.59 0.2 54.06 52.05 0.3 52.23 49.62 0.4 50.31 47.28 0.5 48.26 45.01 0.6 46.05 42.80 0.7 43.74 40.66 0.8 41.39 38.60 0.9 39.06 36.63 1.0 36.80 34.76

[0096] Figure 6A , Figure 6B Simulation results of leakage vortex flow characteristics for a reference airfoil and an optimized blade 1 are shown, respectively, verifying the suppression effect of blade 1 on leakage vortex breakup. The reference airfoil and the optimized blade 1 exhibit characteristics as shown in Tables 1 to 4 (and...). Figures 3 to 5 The leaf shape parameter distribution is shown in the figure. See also: Figure 6A The reference airfoil blade experiences leakage vortex breakup and forms a relatively obvious, limited-range recirculation zone 6; see also Figure 6B The optimized blade 1 did not exhibit the obvious limited-range recirculation zone 6, effectively suppressing tip leakage vortex breakup; furthermore, see Figure 9 The flow distribution of the leakage flow along the direction from the leading edge 11 to the trailing edge 12 of the reference airfoil and the optimized blade 1 are shown. Compared with the reference airfoil, the blade 1 of this disclosure can also effectively reduce the flow entrained in the leakage vortex 5, weaken the intensity of the leakage vortex 5, and further improve its stability. It is calculated that the total tip pressure loss of the blade 1 is reduced by 5.2% compared with the reference airfoil, and the aerodynamic efficiency is higher.

[0097] Continue to refer to Figure 9 Compared to the reference blade, the leakage flow of the blade 1 near the leading edge in the blade channel is entrained into the channel vortex 4 by a certain degree of undesirable increase, which can be effectively solved by using rib tip optimization design.

[0098] like Figure 7 , Figure 8 As shown, in one or more embodiments, the blade 1 includes a suction surface 13 formed by the accumulation of suction lines 23 and a pressure surface 14 formed by the accumulation of pressure lines 24; the suction surface 13 has a suction side rib 131 extending outward along the height direction Z at the blade tip 15, and the pressure surface 14 has a pressure side rib 141 extending outward along the height direction Z at the blade tip 15; the outer surface of the pressure side rib 141 is recessed in the direction of the suction surface 13 to form a concave surface 142, and the pressure side rib 141 is inclined in the direction of the pressure surface 14 to form a diagonal rib 143.

[0099] like Figure 8 As shown, the concave surface 142 forms a guide groove on the outer surface of the pressure surface 14, allowing an airflow to flow along the guide groove from the leading edge 11 to the trailing edge 12, preventing it from crossing the tip clearance and forming a leakage flow. Compared to the reference airfoil and blades with conventional straight rib designs, the oblique rib 143 forms a sharper angle, which increases the flow turning angle of the leakage flow at the inlet on the pressure surface side of the tip clearance. This causes a sudden change in the leakage flow at the inlet, forming a larger separation vortex. The larger the separation vortex, the smaller the passage area for gap leakage, and the smaller the leakage flow rate and leakage loss.

[0100] Figure 10 The diagram illustrates the leakage flow distribution obtained using a conventional rib tip design (straight ribs) and an optimized rib tip design of one embodiment. Compared to the conventional rib tip design, the blade with the rib tip design having the concave surface 142 and the oblique rib 143 is more effective in reducing leakage flow near the leading edge and is better at controlling the total pressure loss of the blade 1. Simulation calculations show that the blade 1 of one embodiment, which combines the airfoil optimization according to Tables 1 to 4 with the rib tip optimization having the concave surface 142 and the oblique rib 143, reduces the total pressure loss at the blade tip section by 6.6%.

[0101] As described above, this disclosure also provides a blade assembly, such as an impeller, which includes the blade 1 described in the above embodiments.

[0102] As described above, this disclosure also provides a turbomachinery, such as an aero-engine, which includes the blade 1 described in the above embodiments.

[0103] In addition to the above, this disclosure also provides a blade shaping method, which includes:

[0104] S1. Select a certain leaf shape as the benchmark leaf shape to be optimized;

[0105] S2. The blade tip section profile of the reference blade is optimized by airfoil design to suppress leakage vortex breakage, and the distribution of the airfoil parameters in the height direction is determined according to a predetermined rule to obtain an optimized airfoil.

[0106] S3. Obtain the limited range recirculation zone 6 formed by the tip leakage vortex of the optimized blade, and determine whether the limited range recirculation zone 6 meets the predetermined characteristic limit conditions.

[0107] If not, then repeat steps S2 to S3;

[0108] If so, the design is complete.

[0109] The blade design method described above can suppress leakage vortex breakup, thereby reducing tip leakage loss and improving blade aerodynamic performance.

[0110] Optionally, the blade profile parameters include the back camber angle δ, the angle of attack α, and the leading edge profile angle β. 1k At least one of the installation angles γ.

[0111] In summary, the beneficial technical effects of this disclosure include, but are not limited to, one or a combination of the following:

[0112] 1. By adopting the small backbend angle design of the blade tip section, the curvature of the suction line of the blade cross-section profile increases in the front region of the throat and decreases in the rear region of the throat. This causes the airflow in the front region of the suction surface throat to accelerate faster and the airflow in the rear region of the throat to accelerate slower. This reduces the difference between the peak Mach number at the throat position and the exit Mach number of the blade cascade, which helps to reduce the reverse pressure gradient in the rear region of the throat, thereby improving the stability of the leakage vortex, suppressing leakage vortex breakup, and reducing the blade tip leakage loss.

[0113] 2. The large angle of attack design within the specified range reduces the leakage vortex flow rate, weakens the leakage vortex strength, improves its stability, and suppresses vortex breakage.

[0114] 3. The large leading edge diameter design of the blade tip section is beneficial to improving the angle of attack performance and avoiding flow separation under extreme conditions. At the same time, the value of the dimensionless diameter D of the leading edge is not too large, which can reduce the risk of a deceleration zone before the airflow accelerates to the throat and the flow separation at the suction surface 13, thus facilitating the stability of the flow state.

[0115] While this disclosure has described above with reference to preferred embodiments, it is not intended to limit the scope of this disclosure. Any changes and modifications can be made by those skilled in the art without departing from the spirit and scope of this disclosure. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this disclosure, without departing from the content of the technical solution of this disclosure, shall fall within the protection scope defined by the claims of this disclosure.

Claims

1. A blade (1), characterized in that, Its leaf shape is defined by the cross-sectional profile (2) stacked along the height direction, the cross-sectional profile (2) having a dimensionless leaf height H which is the ratio of the height of the cross-sectional profile (2) to the total height of the blade (1), the dimensionless leaf height H = 1 is the leaf tip (15), the dimensionless leaf height H = 0 is the leaf root (16); the cross-sectional profile (2) also has a backbend angle δ; At the dimensionless leaf height H = 1, the backbend angle δ = 13°, and has a numerical scale. Tolerance range of ±20%.

2. The blade (1) as described in claim 1, characterized in that, The backbend angle δ is defined by the exit Mach number of the blade cascade (3) composed of the plurality of blades (1), and satisfies the formula: -20Ma exit +31.5≤δ≤-25Ma exit +39 In the formula, Ma exit The exit Mach number of the cascade; At the dimensionless leaf height H = 1, the backbend angle δ takes its minimum value.

3. The blade (1) as described in claim 1, characterized in that, The blade (1) has an angle of attack α; At the dimensionless blade height H = 1, the angle of attack α is a positive angle of attack and is within the range of 0° to 5°.

4. The blade (1) as claimed in claim 1, characterized in that, The cross-sectional profile (2) has a dimensionless leading edge diameter D; At the dimensionless leaf height H = 1, the dimensionless diameter of the leading edge D = 0.87, and has a tolerance range of ±20% of the numerical ratio.

5. The blade (1) as claimed in claim 1, characterized in that, The cross-sectional profile (2) has a leading edge construction angle β 1k ; At the dimensionless leaf height H = 1, the leading edge construction angle β 1k =74.09°, and has a tolerance range of ±15% of the numerical ratio.

6. The blade (1) as claimed in claim 1, characterized in that, The cross-sectional profile (2) has an installation angle γ; At the dimensionless blade height H = 1, the installation angle γ = 34.76°, and has a tolerance range of ±5% of the numerical ratio.

7. The blade (1) as claimed in claim 1, characterized in that, The blade (1) includes a suction surface (13) and a pressure surface (14); the suction surface (13) has a suction side rib (131) extending outward along the height direction at the blade tip (15), and the pressure surface (14) has a pressure side rib (141) extending outward along the height direction at the blade tip (15); the outer surface of the pressure side rib (141) is recessed in the direction of the suction surface (13) to form an inner concave surface (142), and the pressure side rib (161) is inclined in the direction of the pressure surface (14) to form an oblique rib (143).

8. A blade assembly, characterized in that, Includes the blade (1) as described in any one of claims 1-7.

9. A turbomachinery, characterized in that, Includes the blade (1) as described in any one of claims 1-7.

10. A method for shaping blades, characterized in that, include: S1. Select a certain leaf shape as the benchmark leaf shape to be optimized; S2. Perform blade profile parameter optimization design on the tip section profile of the reference blade profile, and determine the distribution of the blade profile parameters in the height direction according to a predetermined rule to obtain an optimized blade profile; S3. Obtain the limited range of recirculation zone formed by the tip leakage vortex of the optimized blade, and determine whether the limited range of recirculation zone meets the predetermined characteristic conditions; If not, then repeat steps S2 to S3; If so, the design is complete.

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