Blade structure for inhibiting stall of fan and fan

Abstract

The invention discloses a blade structure for inhibiting stall of a fan and the fan. The blade structure comprises a blade and a plurality of groups of vortex generators, a stall suppression area is arranged on the suction surface of the blade, the multiple sets of vortex generators are arranged in the stall suppression area in the spanwise direction of the blade, and the heights of the multiple sets of vortex generators are gradually reduced in the direction away from the blade root. In the adjacent vortex generators, the ratio of the chordwise distance from one vortex generator close to the blade tip to the front edge of the blade to the chord length of the blade corresponding to the position of the vortex generator is not smaller than the ratio of the chordwise distance from the other vortex generator to the front edge of the blade to the chord length of the blade corresponding to the position of the vortex generator. According to the method, the arrangement position and structural parameters of the vortex generator can be designed, so that the vortex generator has a better stall inhibition effect on the fan.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wind power generation, and particularly relates to stall inhibition of large wind turbines, and specifically relates to a blade structure for inhibiting stall of a wind turbine. BACKGROUND

[0002] As a core form of renewable energy, the safety and stability of the operation of a wind turbine directly determine the energy utilization efficiency. The wind turbine blade is a key component for capturing wind energy and needs to withstand the influence of complex wind conditions (such as turbulence, gust, and sudden wind shear) during operation. The stall phenomenon of the wind turbine is one of the core aerodynamic problems threatening the safety of the unit.

[0003] The stall of the wind turbine refers to a non-steady flow phenomenon that when the angle of attack (the angle between the chord line of the blade and the direction of the incoming flow) exceeds the critical value, the boundary layer on the surface of the blade separates in a large range due to the increase of the adverse pressure gradient, resulting in a sharp drop in the lift coefficient and a sharp increase in the drag coefficient. The occurrence of stall will cause serious consequences: on the one hand, the sharp drop in lift will cause the output power of the unit to drop suddenly, affecting the stability of power generation; on the other hand, the periodic airflow pulsation caused by separation will intensify the fatigue of the blade structure, shorten the service life of the blade, and even induce major safety accidents such as vibration failure (such as flutter) of the blade.

[0004] In order to inhibit stall, the existing scheme often uses flow control means, among which the vortex generator (VG) becomes one of the most potential technical schemes due to its simple structure, low cost and no need for additional energy consumption. The core principle is that by arranging a thin perturbation element (such as a cylinder or an airfoil) on the surface of the blade, periodic vortexes are induced to generate, the high kinetic energy of the external fluid is rolled into the boundary layer, and the energy of the boundary layer is supplemented, so as to delay or inhibit the separation of the boundary layer.

[0005] At present, the setting and optimization of the vortex generator on the wind turbine blade mainly focus on the following two aspects: 1. Structural design and material optimization of the vortex generator: the existing scheme has developed various structural forms of VG for different types of blades (such as horizontal axis wind turbine blades and vertical axis wind turbine blades), including cylindrical, airfoil, sawtooth and combined types. The material selection gradually expands from the initial aluminum alloy to composite materials, high molecular polymers, etc.

[0006] 2. Aerodynamic performance simulation and experimental verification of vortex generators: Some solutions analyze the influence of VG parameters such as angle of attack on the boundary layer through CFD simulation or wind tunnel test. For example, patent CN118462465A discloses a wind turbine blade vortex generator, which relates to the field of wind power technology. It solves the problem of separation of boundary layer during rotation of the fan in the prior art, which increases the resistance of the blade and affects the power generation capacity of the fan. The device is a wind turbine blade vortex generator, a bottom plate for mounting and fixing on the fan blade; two fins are symmetrically installed on the bottom plate, the fins are provided with horizontal side, inclined side and vertical side, the horizontal side, inclined side and vertical side are sequentially connected end to end, the horizontal side is used for contacting and mounting on the bottom plate, the inclined side extends away from the bottom plate from the connection point of the horizontal side and is connected to the vertical side, the inclined side is used to face the airflow direction, the vertical side is perpendicular to the rotation direction of the fan blade, and the end of the two fins facing the airflow direction is closer to the end of the two fins facing the rotation direction of the fan blade.

[0007] However, although the existing solutions have made progress in structural design and performance verification, they lack targeted research on the installation position of the vortex generator on the blade, resulting in that the actual anti-stall effect does not meet the expectation. The main performance is: 1. Empirical selection of VG position; Specifically, the existing solutions are based on simplified model assumptions or empirical rules, without fully considering the differences in boundary layer characteristics of different regions of the blade (suction surface / pressure surface, leading edge / middle trailing edge, blade root / blade tip) in the stall triggering process. 2. Unreasonable position layout; Specifically, there is a lack of coupling analysis of stall triggering mechanism and VG disturbance characteristics, and the installation position of the existing VG often deviates from the optimal region.

[0008] Therefore, how to make the vortex generator on the blade can fully suppress stall is a problem that those skilled in the art need to solve. SUMMARY

[0009] In view of the defects in the prior art, the present application provides a blade structure for suppressing stall of a fan and a fan. The arrangement of the vortex generator can be optimized to have better stall suppression effect on the fan.

[0010] In a first aspect, the present application provides a blade structure for suppressing stall of a fan, comprising a blade and a plurality of vortex generators. The suction surface of the blade is provided with a stall inhibition zone, and a plurality of vortex generators are arranged in the stall inhibition zone along the blade span direction, the height of the plurality of vortex generators gradually decreases from the direction away from the blade root; in adjacent groups of vortex generators, the ratio of the chordwise distance from the blade leading edge to the vortex generator close to the blade tip to the blade chord length corresponding to the position of the vortex generator is not less than the ratio of the chordwise distance from the blade leading edge to the other vortex generator to the blade chord length corresponding to the position of the other vortex generator. The chordwise distance is the distance from the projection of the vortex generator on the blade chord length to the blade leading edge along the chord length direction.

[0011] Further, the blade is a DU airfoil, a NACA airfoil or an HQ airfoil.

[0012] Further, the vortex generator is a triangular vortex generator or a wedge-shaped vortex generator.

[0013] Further, the vortex generator comprises a base plate and a plurality of fins, and the plurality of fins are arranged on the base plate along the blade span direction.

[0014] Further, the height of the fin gradually increases from the blade leading edge to the trailing edge, and the ratio of the length to the height of the fin is 1.7-2.5.

[0015] Further, the ratio of the chordwise distance from the blade leading edge to the vortex generator to the blade chord length corresponding to the position of the vortex generator is 0.2-0.6.

[0016] Further, the stall inhibition zone is located in a region with a relative thickness of 20%-60% of the blade; wherein the relative thickness is the ratio of the maximum thickness perpendicular to the chord length to the chord length.

[0017] Further, the stall inhibition zone comprises a plurality of first stall inhibition sub-zones and a plurality of second stall inhibition sub-zones, the relative thickness of the blade at the position of the first stall inhibition sub-zone is not less than the relative thickness of the blade at the position of the second stall inhibition sub-zone, and at least one group of vortex generators is arranged in each first stall inhibition sub-zone and second stall inhibition sub-zone. In adjacent first stall inhibition sub-zones and second stall inhibition sub-zones, the length of the first stall inhibition sub-zone along the blade span direction is not less than the length of the second stall inhibition sub-zone along the blade span direction.

[0018] Further, the ratio of the total length of the plurality of first stall inhibition sub-zones along the blade span direction to the total length of the plurality of second stall inhibition sub-zones along the blade span direction is 2.4-2.9.

[0019] Further, the length of the first stall inhibition sub-zone in the blade span direction gradually increases in the direction of decreasing relative blade thickness; the length of the second stall inhibition sub-zone in the blade span direction gradually increases in the direction of decreasing relative blade thickness; the length of the first stall inhibition sub-zone adjacent to the second stall inhibition sub-zone in the blade span direction is not less than the length of any second stall inhibition sub-zone in the blade span direction.

[0020] Further, the ratio of the length of the first stall inhibition sub-zone adjacent to the second stall inhibition sub-zone in the blade span direction to the length of the second stall inhibition sub-zone farthest from the first stall inhibition sub-zone in the blade span direction is 1.6-2.1.

[0021] In a second aspect, the present application also provides a fan comprising the above blade structure.

[0022] The blade structure for inhibiting stall of a fan and the fan provided by the present application have at least the following beneficial effects: (1) By arranging vortex generators with a height gradually decreasing from the direction away from the blade root, the vortex generators can adapt to the characteristics of the thick boundary layer of the blade root and the thin boundary layer of the blade tip, and better achieve stall inhibition of the blade. In adjacent vortex generators, the ratio of the chordwise distance from the leading edge of the blade tip group of vortex generators to the blade chord length corresponding to its position is not less than that of the other group of vortex generators, which can precisely match the variation of the boundary layer along the spanwise thickness and the adverse pressure gradient, and significantly improve the stall inhibition effect.

[0023] (2) By designing the position and structural parameters of the vortex generators, the vortex generators and the blade can have a good synergistic effect, and ultimately the stall inhibition of the stall region on the blade can be achieved to the greatest extent.

[0024] (3) By limiting the position of the stall inhibition region where the vortex generators are located, the total length ratio of different stall inhibition sub-zones can be combined with the position of the stall inhibition region to limit the position of the vortex generators on the blade, and ultimately the vortex generators have the best stall inhibition effect on the blade. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 FIG. 1 is a structural schematic diagram of a blade structure for inhibiting stall of a fan provided by the present application; Figures 2 to 5 FIG. 2 is a structural schematic diagram of various vortex generators provided by the present application; Figure 6 FIG. 3 is a power output simulation schematic diagram of a certain embodiment of the present application under different wind speeds.

[0026] FIG. 4 is a schematic diagram of the reference signs. X direction is the blade span direction, and Y direction is the direction from the leading edge to the trailing edge of the blade. DETAILED DESCRIPTION

[0027] For better understanding of the above technical solutions, the above technical solutions will be described in detail below in combination with the drawings of the specification and specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the present application.

[0028] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. "Plural" generally includes at least two.

[0029] It should also be noted that the terms "comprise", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the goods or devices comprising a series of elements not only include those elements, but also include other elements not explicitly listed, or include elements inherent to such goods or devices. Without more limitations, the element defined by the sentence "comprises a" does not exclude the presence of other identical elements in the goods or devices comprising the element.

[0030] As shown in Figure 1 The present application provides a fan comprising a blade structure for suppressing stall of the fan, the blade structure comprising a blade and a plurality of vortex generators; The suction surface of the blade is provided with a stall suppression zone (the area shown by a1+a2+a3+b1+b2), and the plurality of vortex generators are arranged in the stall suppression zone along the span direction of the blade, and the height of the plurality of vortex generators gradually decreases from the direction away from the blade root; in adjacent groups of vortex generators, the ratio of the chordwise distance from the tip of a group of vortex generators to the leading edge of the blade to the chord length of the blade corresponding to the position of the group of vortex generators is not less than the ratio of the chordwise distance from the tip of another group of vortex generators to the leading edge of the blade to the chord length of the blade corresponding to the position of the group of vortex generators. Wherein, the blade is a DU airfoil, and the chordwise distance is the distance from the projection of the vortex generator on the chord length to the leading edge of the blade along the chord length direction.

[0031] The height of the vortex generator gradually decreases from the direction away from the blade root, which can adapt to the characteristics of the thick boundary layer of the blade root and the thin boundary layer of the blade tip. In the adjacent vortex generators, the chordwise distance from the blade tip of a group of vortex generators near the blade tip to the corresponding blade chord length is not less than that of another group of vortex generators, which can strengthen the coverage of the high adverse pressure gradient area and significantly improve the stall inhibition effect by precisely matching the boundary layer along the spanwise thickness and the adverse pressure gradient change. Specifically, the vortex generator near the blade root can penetrate the thick boundary layer to supplement the deep energy and inhibit local separation; the vortex generator near the blade tip can match the thin boundary layer and be arranged in the maximum adverse pressure gradient area to directly disturb the high separation risk area and delay the stall angle of attack; at the same time, it can also optimize the vortex generation and energy transfer efficiency, reduce flow blockage and structural stress concentration, and finally realize the coordinated improvement of aerodynamic efficiency (such as lift-drag ratio improvement) and structural reliability (such as fatigue life extension).

[0032] The vortex generator in the application can be a triangular vortex generator or a wedge-shaped vortex generator. Specifically, the vortex generator comprises a base plate and a plurality of fins, and the plurality of fins are arranged on the base plate in the spanwise direction of the blade. The vortex generator is fixed to the blade through the base plate, and specifically, the length direction of the base plate with at least two fins is parallel to the spanwise direction / relative height reduction direction of the blade, as shown in Figures 2 to 4 When the vortex generator has only one base plate and one fin, the length of the base plate is basically consistent with the fin, and the fin is oriented towards the leading edge. The cross section of the fin is wedge-shaped, and the base plate is spindle-shaped. In order to improve the fixing effect of the vortex generator and the blade, the back surface of the base plate and the blade can be roughened, so that the roughness of the back surface of the base plate is greater than 6.3 μm. In addition, the height of the fin fixed on the base plate can gradually increase from the leading edge to the trailing edge of the blade, and the ratio of the length to the height of the fin is 1.7-2.5, preferably 1.95-2.15. The adjacent fins on the base plate can be mirror image structures. In order to smooth the connection position of the fin and the base plate, a circular arc transition section is provided at the connection position of the fin and the base plate. At the same time, in order to reduce the influence of the base plate on the airflow, the base plate can be smoothed, for example, a round corner or a chamfer structure is provided at the edge of the base plate. The vortex generator of the application has good structural strength, flow control efficiency and manufacturing process adaptability, and the ratio of the thickness of the fin to the thickness of the base plate can be set to 0.9-1, preferably 0.92-0.97, which can more accurately optimize the boundary layer disturbance effect.

[0033] Based on the structural strength consideration of the vortex generator, the number of fins on the base plate can be set, for example, the number of fins on a single base plate can be set to 2-16, or 1 fin can be set on a single base plate; preferably, the number of fins on a single base plate is set to 4-16, and the appropriate number of fins can be ensured within the structural strength; wherein, when the number of fins on a single base plate is greater than 4, as shown in Figure 2 , a triangular cross-section fin can be used, and an arc-shaped transition is used between the fin and the floor; when the number of fins on a single base plate is 4, as shown in Figure 3 , the fin is composed of a first fin close to the leading edge of the blade and a second fin provided at the tail of the first fin, the first fin and the second fin are integrally formed, wherein the cross-section of the first fin is triangular, and the second fin is wedge-shaped, specifically, the cross-section of the second fin is the same as that of the blade, only the size ratio is different; adjacent fins are paired and mirror images of each other, the four fins on the base plate are divided into two pairs, and the opposite sides of each pair of fins are flat, and the opposite sides form an arc surface at the position of the second fin; in addition, the two fins in each pair of fins are open from one end close to the leading edge to the tail of the second fin. When the number of fins on a single base plate is 2, as shown in Figure 4 , a ladder-shaped table is formed on a single base plate, two fins are fixed on the ladder-shaped table along the waist of the ladder, and the fin is triangular. When the number of fins on a single base plate is 1, as shown in Figure 5 , the bottom surface and the top surface of the base plate are both spindle-shaped, the bottom surface and the top surface form a table structure, the fin is vertically fixed on the top surface of the base plate, the fin is composed of a third fin close to the leading edge of the blade and a fourth fin provided at the tail of the third fin, the third fin and the fourth fin are integrally formed, wherein the cross-section of the first fin is triangular, and the second fin is a water drop structure; in addition, a notch for direction recognition and positioning is provided on the base plate.

[0034] In order to ensure that the fin has a good effect on the airflow, the angle between each fin and the blade span can be pre-set, specifically, the angle between the fin and the blade span can be in the range of 76°-104°, preferably, the angle between the fin and the blade span can be in the range of 78°-102°; wherein, the angle between the fin and the blade span is not 90°. In actual application scenarios, since the relative thickness of the blade is continuously changing, the height of the vortex generator at different positions can be integerized based on the expected parameter limit and design, or the vortex generator within the predetermined range can be averaged after taking the integer to obtain, so that the actual application of the vortex generator is more easily fitted to the actual generation. When integerizing or rounding, the height of the obtained vortex generator is close to and higher than the theoretical design value (expected parameter limit and design).

[0035] The stall suppression region may include multiple first stall suppression sub-regions (a1+a2+a3) and multiple second stall suppression sub-regions (b1+b2) arranged sequentially along the blade span. The relative blade thickness at the location of the first stall suppression sub-region is not less than the relative blade thickness at the location of the second stall suppression sub-region. Each first and second stall suppression sub-region is equipped with at least one set of vortex generators. In adjacent first and second stall suppression sub-regions, the length of the first stall suppression sub-region along the blade span is not less than the length of the second stall suppression sub-region along the blade span. Multiple first stall suppression sub-regions are arranged continuously along the blade span, and multiple second stall suppression sub-regions may also be arranged continuously along the blade span. Furthermore, in the blade span, one first stall suppression sub-region connects with one second stall suppression sub-region, i.e., the first and second stall suppression sub-regions are arranged continuously along the blade span, forming a stall suppression region located on the blade. The boundaries between different stall suppression sub-regions (adjacent first stall suppression sub-regions, adjacent second stall suppression sub-regions, and adjacent first and second stall suppression sub-regions) can be determined by vortex generators located at the edges of the stall suppression sub-regions. For example, the midpoint between the nearest adjacent vortex generators located at the edges of two stall suppression sub-regions forms the boundary demarcation point. Connecting multiple boundary demarcation points on the same edge side sequentially forms the boundary demarcation of adjacent stall suppression sub-regions. Furthermore, the boundaries of stall suppression sub-regions along the blade span are demarcated by multiple vortex generators near the leading and trailing edges of each stall suppression sub-region. Specifically, for multiple vortex generators near the leading edge in a stall suppression sub-region, their points / edges near the leading edge serve as leading boundary demarcation points / lines. Connecting multiple leading boundary demarcation points / lines sequentially forms the boundary demarcation of the stall suppression sub-region near the leading edge. Similarly, the boundary demarcation of the stall suppression sub-region near the trailing edge uses the same method. Furthermore, the stall suppression sub-regions of the blade structure in this invention can be directly divided based on the blade itself. In practical applications, the distance between the vortex generator located at the edge of each stall suppression sub-region and the leading / trailing edge of the blade, as well as the relative thickness of the blade at the location of the vortex generator, are used to determine the sub-regions. After determining the stall suppression sub-regions on the blade, vortex generators corresponding to the sub-regions are placed at their edges. Other vortex generators are then arranged according to a preset spacing between adjacent vortex generators. This invention, through the division of stall suppression sub-regions, enables precise positioning of the vortex generators, ensuring that they achieve the desired suppression effect in practical applications.

[0036] Since the blade leading edge is an airflow acceleration zone, if the vortex generator is arranged too close to the leading edge (i.e. the chordwise distance from the vortex generator to the blade leading edge is too small compared to the blade chord length corresponding to the position of the vortex generator), the disturbance characteristics and the boundary layer state will not match, resulting in flow blockage and early local separation, and the vortex diffusion range is limited and cannot cover the main separation zone. In addition, the blade trailing edge is the final area of flow separation, if the vortex generator is arranged too close to the trailing edge (i.e. the chordwise distance from the vortex generator to the blade leading edge is too large compared to the blade chord length corresponding to the position of the vortex generator), the disturbance timing and separation process will not match, resulting in rapid dissipation of vortex, inability to suppress separation, and interference with the trailing edge structure, reducing the reliability of the blade. Based on this, the blade structure can be designed by adjusting the position and structural parameters of the vortex generator to maximize the stall suppression in the stall region of the blade. Specifically, the ratio of the chordwise distance from the vortex generator to the blade leading edge to the blade chord length corresponding to the position of the vortex generator is 0.2-0.6; preferably, the ratio of the chordwise distance from the vortex generator to the blade leading edge to the blade chord length corresponding to the position of the vortex generator is 0.3-0.45. Correspondingly, since the chord length of the region corresponding to the first stall suppression sub-zone of the blade varies greatly, the chordwise distance from the vortex generator to the blade leading edge corresponding to the region is large; specifically, the chordwise distance from the vortex generator to the blade leading edge gradually increases along the blade span from the blade root to the position of the maximum blade chord length; the chordwise distance from the vortex generator to the blade leading edge gradually decreases along the blade span from the position of the maximum blade chord length to the blade tip. The chordwise distance from the vortex generator to the blade leading edge corresponding to the position of the maximum blade chord length is in the range of 1-1.2 m, the chordwise distance from the vortex generator to the blade leading edge close to the blade root is in the range of 0.8-0.87 m, and the chordwise distance from the vortex generator to the blade leading edge close to the blade tip is in the range of 0.6-0.68 m.

[0037] The core close to the blade root region is a mildly disturbed boundary layer, which supplements the energy of low-speed flow and prevents local adverse pressure gradient from causing separation. The core close to the blade tip region is a strongly disturbed boundary layer, which inhibits airflow from separating in the high separation risk area. If the length of the first stall inhibition sub-area in the spanwise direction is too long, vortex diffusion will be too fast, energy will be wasted, flow blockage and pressure loss will increase, and local separation will be advanced. Correspondingly, if the length of the second stall inhibition sub-area in the spanwise direction is too short, the key separation area will not be covered, and the vortex energy will be concentrated but diffuse too fast. Therefore, in order to ensure that the vortex generators in the multiple stall inhibition sub-areas can better cooperate to achieve stall inhibition of the blade, the length of the different stall inhibition sub-areas in the spanwise direction of the blade can be adjusted, and the parameters of the vortex generators therein can be limited. Specifically, the ratio of the total length of the multiple first stall inhibition sub-areas in the spanwise direction of the blade to the total length of the multiple second stall inhibition sub-areas in the spanwise direction of the blade is 2.4-2.9; preferably, the ratio of the total length of the multiple first stall inhibition sub-areas in the spanwise direction of the blade to the total length of the multiple second stall inhibition sub-areas in the spanwise direction of the blade is 2.65. In addition, since the boundary layer characteristics of different regions on the blade change to some extent, in order to avoid the fact that the first stall inhibition sub-area and the second stall inhibition sub-area still cannot achieve the expected effect when they meet the above ratio, the position of the stall inhibition area can also be limited, so that the total length ratio of the different stall inhibition sub-areas and the position of the stall inhibition area are combined to limit the position of the vortex generator on the blade, and finally the best stall inhibition effect of the blade is achieved. The stall inhibition area can be located in the region with a relative thickness of 20%-60% of the blade; the relative thickness of the blade is the ratio of the maximum thickness perpendicular to the chord length to the chord length. Preferably, the stall inhibition area is located in the region with a relative thickness of 21%-51% of the blade. In actual application, if the relative thickness of the blade where the stall inhibition area is located is too small, the vortex will be disturbed too much, energy will be wasted, the key separation area will not be covered, the stall risk will surge, and the vortex life will be short and the mixing efficiency will be low; if the relative thickness of the blade where the stall inhibition area is located is too large, the vortex will not penetrate enough, the disturbance will fail, the flow blockage and pressure loss will surge, and the structural stress concentration and fatigue failure will occur. Therefore, by setting the stall inhibition area corresponding to the vortex generator at a suitable relative thickness position of the blade, the vortex generator can achieve the best stall inhibition and reduce the impact on the blade structure.

[0038] Further, the length of the first stall inhibition sub-zone in the blade span direction gradually increases along the direction of decreasing relative thickness; the length of the second stall inhibition sub-zone in the blade span direction gradually increases along the direction of decreasing relative thickness; the length of the first stall inhibition sub-zone adjacent to the second stall inhibition sub-zone in the blade span direction is not less than the length of any second stall inhibition sub-zone in the blade span direction. Correspondingly, the vortex generator size in the stall inhibition zone monotonically decreases in the blade span direction, that is, the vortex generator size in the first stall inhibition sub-zone and the second stall inhibition sub-zone gradually decreases or is the same in the blade span direction; preferably, the vortex generator size in the first stall inhibition sub-zone and the second stall inhibition sub-zone gradually decreases in the blade span direction. Wherein, the vortex generator size in the same stall inhibition sub-zone (first stall inhibition sub-zone or second stall inhibition sub-zone) is the same or within a preset difference range. If the vortex generator size in the same stall inhibition sub-zone is within the preset difference range, the preset difference range can be determined in advance according to the actual situation, that is, the range in which some vortex generators have a certain size difference from the preset size vortex generators; the vortex generator corresponding to the maximum size within the preset difference range is not more than the minimum size of the vortex generator in the adjacent stall inhibition sub-zone upstream in the blade span direction, and the minimum size of the vortex generator within the preset difference range is not less than the maximum size of the vortex generator in the adjacent stall inhibition sub-zone downstream in the blade span direction. Through this setting, the vortex generator in each stall inhibition sub-zone can be fine-tuned according to the actual application scenario to achieve better stall inhibition effect.

[0039] In order to make the length of the first stall inhibition sub-zone or the second stall inhibition sub-zone set in the blade span direction have better effect, the arrangement length of each group of vortex generators located in the stall inhibition sub-zone can be designed. Specifically, the ratio of the length of the first stall inhibition sub-zone adjacent to the second stall inhibition sub-zone in the blade span direction to the length of the second stall inhibition sub-zone farthest from the first stall inhibition sub-zone in the blade span direction is 1.6-2.1, since the vortex generator corresponds to the length of the stall inhibition sub-zone, therefore, the ratio of the length of the vortex generator in the two stall inhibition sub-zones in the blade span direction is 1.6-2.1; preferably, the ratio of the length of the first stall inhibition sub-zone farthest from the blade root in the blade span direction to the length of the second stall inhibition sub-zone closest to the blade tip in the blade span direction is 1.85.

[0040] In an actual application scenario, the starting position of the stall inhibition zone is gradually designed along the span direction close to the blade root position, specifically, the stall inhibition zone is from the position of 51% relative thickness of the blade to the position of 21.68% relative thickness of the blade; wherein the suction surface corresponding to 25.73%-30.54%, 30.54%-42%, 42%-51% relative thickness of the blade is divided into a first stall inhibition sub-zone (i.e. there are three stall inhibition sub-zones) respectively, and the suction surface corresponding to 21.68%-23.63%, 23.63%-25.73% relative thickness of the blade is divided into a second stall inhibition sub-zone (i.e. there are two stall inhibition sub-zones) respectively.

[0041] Taking a blade with a length of 38 m as an example, the arrangement of the vortex generator is determined through different cross-sectional positions of the blade. Specifically, taking the cross-sectional position at the blade root as the starting point, the vortex generator is arranged from the blade spanwise to the blade tip; wherein, for the 38 m blade, the structure is specifically as follows: the cross-sectional position at the blade root is 0 m, the chord length at this cross-sectional position is 1.88 m, the relative thickness is 100%, no vortex generator is arranged at this cross-sectional position, the cross-sectional position at the blade tip is 38 m, the chord length at this cross-sectional position is 0.05 m, the relative thickness is 18%, no vortex generator is arranged, further, when the cross-sectional position is 0.5 m, the corresponding chord length and relative thickness are the same as those at the blade root, the chord length of the blade gradually increases from the cross-sectional position of 0.5 m to the cross-sectional position of 6 m and reaches the maximum, the chord length gradually decreases from the cross-sectional position with the maximum chord length towards the blade tip direction until it decreases to 0.05 m at the blade tip position. When the stall inhibition zone and the corresponding vortex generator are arranged on the 38 m blade, the vortex generator of the first first stall inhibition sub-zone a1 is arranged in the cross-sectional position range of 4 m~7.5 m, the vortex generator of the second first stall inhibition sub-zone a2 is arranged in the cross-sectional position range of 7.5 m~12.5 m, the vortex generator of the third first stall inhibition sub-zone a3 is arranged in the cross-sectional position range of 12.5 m~19.5 m, the vortex generator of the first second stall inhibition sub-zone b1 is arranged in the cross-sectional position range of 19.5 m~22.5 m, and the vortex generator of the second second stall inhibition sub-zone b2 is arranged in the cross-sectional position range of 22.5 m~27.0 m. Wherein, in the first first stall inhibition sub-zone a1, the ratio of the chordwise distance from the vortex generator to the blade leading edge to the blade chord length corresponding to the position of the vortex generator is 0.3, and the height of the vortex generator is 25 mm; in the second first stall inhibition sub-zone a2, the ratio of the chordwise distance from the vortex generator to the blade leading edge to the blade chord length corresponding to the position of the vortex generator is 0.4, and the height of the vortex generator is 20 mm; in the third first stall inhibition sub-zone a3, the ratio of the chordwise distance from the vortex generator to the blade leading edge to the blade chord length corresponding to the position of the vortex generator is 0.4, and the height of the vortex generator is 15 mm; in the first second stall inhibition sub-zone b1, the ratio of the chordwise distance from the vortex generator to the blade leading edge to the blade chord length corresponding to the position of the vortex generator is 0.4, and the height of the vortex generator is 10 mm; in the second second stall inhibition sub-zone b2, the ratio of the chordwise distance from the vortex generator to the blade leading edge to the blade chord length corresponding to the position of the vortex generator is 0.4, and the height of the vortex generator is 5 mm, for details, refer to Table 1.

[0042] Table 1 arrangement data table of vortex generator on 38 m blade

[0043] Based on the vortex generator arrangement parameters in Table 1, the vortex generators are arranged on the 38m blade sample (legend: with VG), while the parallel blade sample without vortex generator arrangement (legend: without VG) is set, and the power output experiment simulation under different wind speed conditions is carried out for the two samples, and the simulation results are as shown in Figure 6 After the vortex generator is arranged on the blade, the overall power output power can be increased under the same wind speed, thereby having a better stall inhibition effect, especially when the blade runs for a certain time and the roughness appears on the surface of the blade, the power output curve of the sample with the vortex generator is better, and the power output curve of the sample without the vortex generator will have greater fluctuation, which is not conducive to the long-term stable operation of the fan.

[0044] Although the preferred embodiments of the present application have been described, those skilled in the art can make further changes and modifications to the embodiments once they know the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including all the preferred embodiments and all changes and modifications falling within the scope of the present application. Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. A blade structure for suppressing wind turbine stall, characterized in that, Includes blades and multiple sets of eddy current generators; The suction surface of the blade is provided with a stall suppression zone, and multiple sets of vortex generators are arranged along the blade span in the stall suppression zone. The height of the multiple sets of vortex generators gradually decreases from the direction away from the blade root. In adjacent groups of vortex generators, the ratio of the chordal distance from the vortex generator closest to the blade tip to the blade leading edge to the blade chord length corresponding to its position is not less than the ratio of the chordal distance from the vortex generator to the blade leading edge to the blade chord length corresponding to its position in the other group of vortex generators.

2. The blade structure as described in claim 1, characterized in that, The eddy current generator includes a base plate and multiple fins, which are arranged at intervals along the blade span on the base plate.

3. The blade structure as described in claim 2, characterized in that, The height of the fins gradually increases from the leading edge to the trailing edge of the blade, and the ratio of fin length to height is 1.7 to 2.

5.

4. The blade structure as described in any one of claims 1 to 3, characterized in that, The ratio of the chordal distance from the eddy current generator to the leading edge of the blade to the blade chord length corresponding to its position is 0.2~0.

6.

5. The blade structure as described in claim 4, characterized in that, The stall suppression zone is located within the area of ​​20% to 60% of the blade's relative thickness; where the relative thickness is the ratio of the maximum thickness perpendicular to the chord length to the chord length.

6. The blade structure as described in claim 5, characterized in that, The stall suppression region includes multiple first stall suppression sub-regions and multiple second stall suppression sub-regions. The relative thickness of the blades at the location of the first stall suppression sub-region is not less than the relative thickness of the blades at the location of the second stall suppression sub-region. Each first stall suppression sub-region and each second stall suppression sub-region is equipped with at least one set of eddy current generators. In the adjacent first stall suppression sub-region and second stall suppression sub-region, the length of the first stall suppression sub-region along the blade span is not less than the length of the second stall suppression sub-region along the blade span.

7. The blade structure as described in claim 6, characterized in that, The ratio of the total length of multiple first stall suppression sub-regions in the blade span direction to the total length of multiple second stall suppression sub-regions in the blade span direction is 2.4 to 2.

9.

8. The blade structure as described in claim 7, characterized in that, The lengths of multiple first stall suppression sub-regions in the blade span direction gradually increase along the direction of decreasing relative blade thickness; the lengths of multiple second stall suppression sub-regions in the blade span direction gradually increase along the direction of decreasing relative blade thickness; the length of a first stall suppression sub-region adjacent to a second stall suppression sub-region in the blade span direction is not less than the length of any second stall suppression sub-region in the blade span direction.

9. The blade structure as described in claim 8, characterized in that, The ratio of the length of the first stall suppression sub-region adjacent to the second stall suppression sub-region in the blade spanwise direction to the length of the second stall suppression sub-region furthest from the first stall suppression sub-region in the blade spanwise direction is 1.6 to 2.

1.

10. A fan, characterized in that, Includes the blade structure as described in any one of claims 1 to 9.

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