Blade, propeller, power propulsion device and ship

Abstract

The invention provides a blade, a propeller, a power propelling device and a ship, and relates to the technical field of propeller noise control, and the blade comprises a blade root, a blade body and a blade tip which are connected in sequence; the blade body is provided with a first pressure surface and a first suction surface which are oppositely arranged, and in the rotating process of the paddle, fluid can flow from the position of the first pressure surface to the position of the first suction surface; at least a portion of the blade tip is curved toward the first pressure surface. According to the technical scheme, at least one part of the blade tip is bent towards the first pressure surface of the blade body, so that the design mode is beneficial to structural optimization of the blade tip, vortex-induced resonance can be inhibited to a great extent, and noise pollution is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of propeller noise control, and in particular to a blade, a propeller, a power propulsion device and a ship. Background Art

[0002] According to the International Ship Noise Control Regulations and the Guidelines for Reducing Underwater Noise from Commercial Ships issued by the International Maritime Organization (IMO), ships should not cause excessive noise pollution to the surrounding environment when sailing. As the most mainstream and widely used propeller in the current shipbuilding industry, the noise problem of propellers has always been the focus of researchers.

[0003] Propellers usually operate in non-uniform turbulence, and vortex shedding will occur locally at the blade tip, accompanied by cavitation. Experimental studies have found that the vortex shedding phenomenon at the blade tip will cause the propeller vibration to increase and vortex-induced resonance may occur. This phenomenon will greatly increase the vibration noise of the propeller and greatly increase the noise pollution to the surrounding area when the ship is sailing.

[0004] Therefore, how to optimize the structure of the blade tip to reduce the vibration noise caused by vortex-induced resonance is a problem that needs to be solved urgently. Summary of the invention

[0005] In order to solve or improve at least one of the above technical problems, an object of the present invention is to provide a blade.

[0006] Another object of the present invention is to provide a propeller.

[0007] Another object of the present invention is to provide a power propulsion device.

[0008] Another object of the present invention is to provide a ship.

[0009] To achieve the above-mentioned object, the first aspect of the present invention provides a blade, the blade comprising a blade root, a blade body and a blade tip connected in sequence. The blade body has a first pressure surface and a first suction surface arranged opposite to each other. During the rotation of the blade, the fluid can flow from the position of the first pressure surface to the position of the first suction surface. At least a portion of the blade tip is bent toward the first pressure surface.

[0010] The present invention aims to provide a blade, wherein at least a portion of the blade tip is bent toward the first pressure surface of the blade body. This design is conducive to structural optimization of the blade tip, can suppress vortex-induced resonance to a great extent, and reduce noise pollution.

[0011] In addition, the above technical solution provided by the present invention may also have the following additional technical features:

[0012] In some technical solutions, optionally, the blade tip includes a blade tip body and an open annular structure. The blade tip body is connected to the blade body. The open annular structure is arranged at one end of the blade tip body away from the blade body, and at least a portion of the open annular structure is bent toward the first pressure surface.

[0013] In this technical solution, an open annular structure is provided without changing the main blade profile of the propeller, and at least a portion of the open annular structure is bent toward the first pressure surface. This design is conducive to suppressing eddy currents and reducing propeller vibration noise, thereby achieving the purpose of improving the acoustic performance of the propeller and reducing underwater noise pollution of ships.

[0014] In some technical solutions, optionally, the open annular structure has a second pressure surface and a second suction surface that are arranged opposite to each other. The second pressure surface is connected to the first pressure surface and is located on the same side of the blade; the second suction surface is connected to the first suction surface and is located on the same side of the blade. At least a portion of the second suction surface is arranged on a side of the first pressure surface that is away from the first suction surface.

[0015] In this technical solution, the second suction surface and the second pressure surface of the open annular structure are twisted so that at least a part of them is arranged on the side of the first pressure surface away from the first suction surface. This design method is conducive to weakening the tip vortex strength, thereby achieving the purpose of suppressing the vortex-induced vibration of the propeller, and can effectively improve the acoustic performance of the propeller and reduce the underwater noise pollution of the ship.

[0016] In some technical solutions, optionally, the open annular structure and the blade tip body are an integrated structure.

[0017] In this technical solution, this design method does not require changing the main blade shape of the propeller, but only requires bending or twisting the blade tip toward the first pressure surface to form an open annular structure.

[0018] In some technical solutions, optionally, the open annular structure and the blade tip body are separate structures, and the open annular structure is connected to the blade tip body.

[0019] In this technical solution, this design makes it easy for workers to disassemble and assemble the open annular structure, which is beneficial for maintenance or replacement.

[0020] In other words, a part of the blade tip is cut off, and the main body of the blade tip is retained; and an open annular structure with the same line shape as the cross-section is spliced ​​with the cross-section of the blade tip.

[0021] In some technical solutions, optionally, the inner contour of the cross section of the open annular structure is an arc, and the central angle corresponding to the arc is 175 degrees to 185 degrees.

[0022] In this technical solution, this design method can ensure that at least a part of the second suction surface is arranged on the side of the first pressure surface away from the first suction surface, which is beneficial to weaken the tip vortex strength and achieve the purpose of suppressing propeller vortex-induced vibration.

[0023] In some technical solutions, optionally, the radial dimension of the blade is a first dimension, the radial dimension of the open annular structure along the blade is a second dimension, and the second dimension is 4% to 6% of the first dimension.

[0024] In this technical solution, this design ensures that an open annular structure is provided without changing the main blade profile of the propeller, and at least a portion of the open annular structure is bent toward the first pressure surface, which is beneficial to suppressing vortices and reducing propeller vibration noise.

[0025] The second aspect of the present invention provides a propeller, comprising a central shaft and a blade in any one of the above technical solutions. The blade root of the blade is connected to the central shaft.

[0026] Since the propeller includes any one of the blades in the first aspect, it has the beneficial effects of any one of the technical solutions mentioned above, which will not be described in detail here.

[0027] The third aspect of the present invention provides a power propulsion device, comprising a driving member and the propeller in the above technical solution. The propeller is connected to the driving member.

[0028] Since the power propulsion device includes the propeller in the above-mentioned second aspect, it has the beneficial effects of the above-mentioned technical solution, which will not be repeated here.

[0029] A fourth aspect of the present invention provides a ship, comprising a hull and a power propulsion device in the above technical solution. The power propulsion device is connected to a driving member.

[0030] Since the ship includes the power propulsion device in the third aspect above, it has the beneficial effects of the above technical solution, which will not be repeated here.

[0031] Additional aspects and advantages of the technical solutions of the present invention will become apparent in the following description or will be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic diagram of the structure of a blade according to an embodiment of the present invention is shown;

[0033] Figure 2 A structural schematic diagram of a propeller according to an embodiment of the present invention is shown;

[0034] Figure 3 A structural schematic diagram of a propeller according to another embodiment of the present invention is shown;

[0035] Figure 4 A structural schematic diagram of a propeller according to another embodiment of the present invention is shown;

[0036] Figure 5 A structural block diagram of a power propulsion device according to an embodiment of the present invention is shown;

[0037] Figure 6 A structural block diagram of a ship according to an embodiment of the present invention is shown;

[0038] Figure 7 A schematic diagram of a propeller blade tip vortex in the related art is shown;

[0039] Figure 8 A schematic diagram showing a flow field of a blade tip according to an embodiment of the present invention is shown.

[0040] in, Figures 1 to 6 The corresponding relationship between the reference numerals and the component names is as follows:

[0041] 100: blade; 110: blade root; 120: blade body; 121: first pressure surface; 122: first suction surface; 130: blade tip; 131: blade tip body; 132: open annular structure; 133: second pressure surface; 134: second suction surface; 200: propeller; 210: central axis; 300: power propulsion device; 310: driving part; 400: ship; 410: hull. DETAILED DESCRIPTION

[0042] In order to more clearly understand the above-mentioned purposes, features and advantages of the embodiments of the present invention, the embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0043] In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the embodiments of the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present application is not limited to the specific embodiments disclosed below.

[0044] Refer to the following Figures 1 to 8 The following describes a blade 100, a propeller 200, a power propulsion device 300 and a ship 400 provided according to some embodiments of the present invention.

[0045] In one embodiment according to the present invention, Figure 1As shown, the blade 100 includes a blade root 110, a blade body 120 and a blade tip 130 connected in sequence. Among them, the portion of the blade 100 close to the central axis 210 is called the blade root 110. The blade root 110 is used to connect with the central axis 210 of the propeller 200. Optionally, the blade root 110 and the central axis 210 are detachably connected, which is convenient for the staff to disassemble and assemble the blade 100, which is conducive to maintenance or replacement.

[0046] The blade body 120 is the main part of the blade 100, extending from the blade root 110 to the blade tip 130. The blade body 120 has a certain degree of twist and curvature. The twisted shape can make the angle of attack of the blade 100 at different radial positions reasonable, so as to ensure that each part of the blade 100 can effectively do work on the fluid and generate thrust during the rotation process. The surface of the blade body 120 is usually relatively smooth to reduce the resistance of the fluid.

[0047] The blade body 120 has a first pressure surface 121 and a first suction surface 122 which are arranged opposite to each other. When the blade 100 rotates, the fluid can flow from the first pressure surface 121 to the first suction surface 122 .

[0048] During the rotation of the blade 100 , the pressure of the fluid on the first suction surface 122 of the blade body 120 is lower than the pressure of the fluid on the first pressure surface 121 of the blade body 120 . Therefore, the fluid can flow from the first pressure surface 121 to the first suction surface 122 .

[0049] It should be noted that the blade 100 has a pressure surface and a suction surface that are arranged relatively to each other, wherein the pressure surface of the blade 100 can be understood as the thrust surface of the blade 100, which is used to push the fluid. During the rotation of the blade 100, the pressure of the fluid on the suction surface side of the blade 100 is lower than the pressure of the fluid on the pressure surface side of the blade 100. The first suction surface 122 is part of the suction surface of the blade 100; the first pressure surface 121 is part of the pressure surface of the blade 100.

[0050] The blade tip 130 is the outermost portion of the blade 100. Figure 2 As shown, at least a portion of blade tip 130 is curved toward first pressure surface 121 .

[0051] During the operation of the propeller 200, the blade tip 130 moves at the fastest speed, and the fluid dynamics phenomenon around it is relatively complex. For example, in non-uniform turbulence, the blade tip 130 is prone to vortex shedding, which may be accompanied by cavitation, which may cause the propeller 200 to vibrate and increase noise.

[0052] The present invention aims to provide a blade 100, wherein at least a portion of the blade tip 130 is bent toward the first pressure surface 121 of the blade body 120. This design is conducive to structural optimization of the blade tip 130, can suppress vortex-induced resonance to a great extent, and reduce noise pollution.

[0053] In a specific embodiment, the blade root 110 and the central shaft 210 are detachably connected by key connection or interference fit. In addition, when the blade root 110 and the central shaft 210 are in a connected state, the blade root 110 and the central shaft 210 are relatively fixed in the circumferential direction, so that the central shaft 210 transmits torque to the blade 100.

[0054] Turbulence is a flow state of a fluid (liquid or gas). In turbulence, the particles of the fluid move irregularly, and the values ​​of various physical quantities in the flow field (such as velocity, pressure, etc.) will change randomly with time and spatial position. Non-uniform turbulence means that in the entire flow field, the distribution of these physical quantities is not only randomly changing, but also spatially non-uniform. For example, in a river, due to the shape of the riverbed, changes in water depth, and the presence of obstacles (such as reefs, bridge piers, etc.), the speed and direction of the water flow will vary greatly at different locations. In this case, the water flow is non-uniform turbulence.

[0055] The causes of non-uniform turbulence can be roughly divided into three types: changes in boundary conditions, differences in fluid properties, and external interference.

[0056] Regarding "changes in boundary conditions": When a fluid flows through different boundaries, the friction, resistance, and other effects of the boundaries on the fluid are different, causing physical quantities such as the fluid velocity to change near the boundaries.

[0057] Regarding "differences in fluid properties": If the fluid is a mixture of different components, or if the fluid's physical properties such as temperature and density vary in space, it will also lead to non-uniform turbulence. For example, in the ocean, the flow between seawater layers of different salinity and temperature will produce complex non-uniform turbulence due to density differences.

[0058] Regarding “external interference”: External factors such as vibration, impact of other fluids, etc. can also cause non-uniform turbulence.

[0059] When the propeller 200 is running in non-uniform turbulence, vortex shedding may occur locally at the blade tip 130. This is because the non-uniform turbulence causes the fluid pressure and velocity distribution around the blade tip 130 to be uneven, resulting in the formation and shedding of vortices. These shedding vortices may cause vibrations in the propeller 200 and may be accompanied by cavitation. When the pressure in the vortex drops below the saturated vapor pressure of the liquid, the liquid vaporizes to form bubbles, which is the cavitation phenomenon. The bubbles will quickly collapse in the high-pressure area, generating impact pressure, further increasing the vibration and noise of the propeller 200.

[0060] Applying the blade 100 provided by the present invention to the propeller 200 and optimizing the structure of the blade tip 130 can help suppress vortex-induced resonance, thereby reducing the vibration and noise of the propeller 200 and improving the acoustic performance of the propeller 200.

[0061] In some embodiments, optionally, Figure 2 As shown, the blade tip 130 includes a blade tip body 131 and an open annular structure 132. The blade tip body 131 is connected to the blade body 120. The open annular structure 132 is arranged at one end of the blade tip body 131 away from the blade body 120, and at least a part of the open annular structure 132 is bent toward the first pressure surface 121.

[0062] Without changing the main blade shape of the propeller 200, an open annular structure 132 is provided, and at least a portion of the open annular structure 132 is bent toward the first pressure surface 121. This design is conducive to suppressing eddy currents and reducing the vibration noise of the propeller 200, thereby achieving the purpose of improving the acoustic performance of the propeller 200 and reducing underwater noise pollution of the ship 400.

[0063] In some embodiments, the open annular structure 132 and the blade tip body 131 are optionally integrated. This design does not require changing the main blade shape of the propeller 200, but only requires bending or twisting the blade tip 130 of the blade 100 toward the first pressure surface 121 to form the open annular structure 132.

[0064] It should be emphasized that the open annular structure 132 and the blade tip body 131 are an integrated structure, which has good mechanical properties and high connection strength compared to a split structure, and is conducive to reducing the number of parts and improving assembly efficiency. In addition, this design method will not affect the overall line shape of the blade 100, ensuring the structural performance of the blade 100.

[0065] In a specific embodiment, the blade tip 130 of the blade 100 is twisted 180 degrees toward the first pressure surface 121 to form an open annular structure 132 .

[0066] In some embodiments, optionally, the open annular structure 132 and the blade tip body 131 are separate structures, and the open annular structure 132 is connected to the blade tip body 131. This design makes it convenient for workers to disassemble and assemble the open annular structure 132, which is conducive to maintenance or replacement.

[0067] In other words, a portion of the blade tip 130 is cut off, and the blade tip main body 131 is retained; and the open annular structure 132 having the same linear shape as the truncated surface is spliced ​​with the truncated surface of the blade tip.

[0068] The specific shape and thickness of the open annular structure 132 are appropriately adjusted according to the structural strength requirements.

[0069] In a specific embodiment, a portion of the blade tip 130 is cut off, and then an annular semi-tubular structure having the same linear shape as the cut surface is spliced ​​with the cut surface of the blade tip, wherein the annular semi-tubular structure is an open annular structure 132, and the bending angle is 180 degrees.

[0070] In some embodiments, the blade tip body 131 and the blade body 120 are optionally integrated into a structure, which has good mechanical properties and high connection strength compared to a split structure, and is conducive to reducing the number of parts and improving assembly efficiency. In addition, this design method does not affect the overall line shape of the blade 100, ensuring the structural performance of the blade 100.

[0071] In some embodiments, optionally, the open annular structure 132 has a second pressure surface 133 and a second suction surface 134 that are arranged opposite to each other.

[0072] The second pressure surface 133 is connected to the first pressure surface 121 and is located on the same side of the blade 100 ; the second suction surface 134 is connected to the first suction surface 122 and is located on the same side of the blade 100 .

[0073] It should be noted that the second pressure surface 133 is a part of the pressure surface of the blade 100 ; the second suction surface 134 is a part of the suction surface of the blade 100 .

[0074] At least a portion of the second suction surface 134 is disposed on a side of the first pressure surface 121 away from the first suction surface 122 .

[0075] The second suction surface 134 and the second pressure surface 133 of the open annular structure 132 are twisted so that at least a portion of them is disposed on the side of the first pressure surface 121 away from the first suction surface 122. This design is conducive to weakening the tip vortex strength, thereby achieving the purpose of suppressing the vortex-induced vibration of the propeller 200, and can effectively improve the acoustic performance of the propeller 200 and reduce the underwater noise pollution of the ship 400.

[0076] like Figure 7 and Figure 8As shown, the flow field characteristics of the propeller blade tip vortex in the related art and the flow field characteristics of the blade tip 130 in the present invention are compared, the narrow vortex on the guide edge of the original blade tip suction surface (the second suction surface 134) and the blade tip suction surface reflective flow. In the present invention, when the fluid passes through the blade tip annular structure (the open annular structure 132), the flow smoothly diffuses toward the top of the blade ring (the top of the open annular structure 132), and the blade shape bent toward the pressure surface causes the vortex to diffuse around the ring to the periphery, which greatly suppresses the vortex shedding on the blade tip guide edge, and the vortex intensity also decreases on the ring surface; and when the vortex reaches the tail of the open annular structure 132, the second suction surface 134 has smoothly transitioned to the side of the first pressure surface 121 away from the first suction surface 122, and the vortex intensity is also greatly reduced, and the flow field flows out smoothly along the blade tip of the open annular structure 132, and the previous vortex shedding is basically suppressed.

[0077] In some embodiments, optionally, the inner contour of the cross section of the open annular structure 132 is an arc, and the central angle corresponding to the arc is 175 degrees to 185 degrees.

[0078] In other words, the open annular structure 132 is bent toward the first pressure surface 121, and the bending angle is 175 to 185 degrees. This design ensures that at least a portion of the second suction surface 134 is disposed on the side of the first pressure surface 121 away from the first suction surface 122, which is beneficial to weakening the tip vortex strength and achieving the purpose of suppressing the vortex-induced vibration of the propeller 200.

[0079] In a specific embodiment, the central angle corresponding to the arc is 180 degrees, that is, the bending angle is 180 degrees.

[0080] In some embodiments, optionally, the radial dimension of the blade 100 is a first dimension, and the radial dimension of the open annular structure 132 along the blade 100 is a second dimension, and the second dimension is 4% to 6% of the first dimension.

[0081] This design ensures that the open annular structure 132 is provided without changing the main blade shape of the propeller 200 , and at least a portion of the open annular structure 132 is bent toward the first pressure surface 121 , which is beneficial to suppressing vortexes and reducing vibration noise of the propeller 200 .

[0082] In a specific embodiment, the second dimension is 5% of the first dimension.

[0083] In a specific embodiment, the blade tip 130 of the blade 100 is horizontally truncated according to a first length (0.025m, 5% of the radial dimension of the blade 100); an annular semi-tubular structure (open annular structure 132) with the same line shape as the truncated surface is spliced ​​with the truncated surface, so that the annular semi-tubular structure surrounds the thrust surface of the blade 100 by 180° (the bending angle is 180 degrees); the blade edge is appropriately smoothed; the surrounding diameter of the annular semi-tubular structure is 0.025m.

[0084] In one embodiment according to the present invention, Figure 3 and Figure 4 As shown, the propeller 200 includes a central shaft 210 and a blade 100 in any of the above embodiments, and a blade root 110 of the blade 100 is connected to the central shaft 210 .

[0085] Among them, since the propeller 200 includes any blade 100 in the above-mentioned first aspect, it has the beneficial effects of any of the above-mentioned embodiments, which will not be repeated here.

[0086] Optionally, the blade root 110 and the central axis 210 are detachably connected, so that the staff can disassemble and assemble the blade 100 and facilitate maintenance or replacement.

[0087] In a specific embodiment, the blade root 110 and the central shaft 210 are detachably connected by key connection or interference fit. In addition, when the blade root 110 and the central shaft 210 are in a connected state, the blade root 110 and the central shaft 210 are relatively fixed in the circumferential direction, so that the central shaft 210 transmits torque to the blade 100.

[0088] It should be noted that the number of the blades 100 may be two or more, and the number of the blades 100 may be flexibly set according to actual needs.

[0089] In a specific embodiment, Figure 3 and Figure 4 As shown, the number of blades 100 is 4. The radial dimension of propeller 200 is 1 m.

[0090] In one embodiment according to the present invention, Figure 5 As shown, the power propulsion device 300 includes a driving member 310 and the propeller 200 in the above technical solution. The propeller 200 is connected to the driving member 310.

[0091] Since the power propulsion device 300 includes the propeller 200 in the above-mentioned second aspect, it has the beneficial effects of the above-mentioned technical solution, which will not be described in detail here.

[0092] In a specific embodiment, the driving member 310 is a driving motor.

[0093] Optionally, the power propulsion device 300 also includes a reduction device, which is arranged between the propeller 200 and the driving member 310 to transmit torque and match the rotational speed.

[0094] In one embodiment according to the present invention, Figure 6 As shown, the ship 400 includes a hull 410 and the power propulsion device 300 in the above technical solution. The power propulsion device 300 is connected to the driving member 310.

[0095] Since the ship 400 includes the power propulsion device 300 in the third aspect, it has the beneficial effects of the above technical solution, which will not be described in detail here.

[0096] In the present invention, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance; the term "plurality" refers to two or more, unless otherwise clearly defined. The terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0097] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by terms such as “upper”, “lower”, “left”, “right”, “front” and “back” are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation, and therefore, cannot be understood as a limitation on the present invention.

[0098] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0099] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A blade, characterized in that: The blade comprises a blade root (110), a blade body (120) and a blade tip (130) which are connected in sequence; The blade body (120) has a first pressure surface (121) and a first suction surface (122) arranged opposite to each other, and during the rotation of the blade, the fluid can flow from the position of the first pressure surface (121) to the position of the first suction surface (122); At least a portion of the blade tip (130) is bent toward the first pressure surface (121).

2. The blade according to claim 1, characterized in that: The blade tip (130) comprises: A blade tip body (131) connected to the blade body (120); An open annular structure (132) is provided at one end of the blade tip body (131) away from the blade body (120), and at least a portion of the open annular structure (132) is bent toward the first pressure surface (121).

3. The blade according to claim 2, characterized in that: The open annular structure (132) has a second pressure surface (133) and a second suction surface (134) which are arranged opposite to each other, the second pressure surface (133) is connected to the first pressure surface (121) and is located on the same side of the blade; the second suction surface (134) is connected to the first suction surface (122) and is located on the same side of the blade; At least a portion of the second suction surface (134) is disposed on a side of the first pressure surface (121) facing away from the first suction surface (122).

4. The blade according to claim 2, characterized in that: The open annular structure (132) and the blade tip body (131) are an integrated structure.

5. The blade according to claim 2, characterized in that: The open annular structure (132) and the blade tip body (131) are separate structures, and the open annular structure (132) is connected to the blade tip body (131).

6. The blade according to any one of claims 2 to 5, characterized in that The inner contour of the cross section of the open annular structure (132) is an arc, and the central angle corresponding to the arc is 175 degrees to 185 degrees.

7. The blade according to any one of claims 2 to 5, characterized in that The radial dimension of the blade is a first dimension, and the radial dimension of the open annular structure (132) is a second dimension, which is 4% to 6% of the first dimension.

8. A propeller, characterized in that: include: A central axis (210); The blade according to any one of claims 1 to 7, wherein the blade root (110) of the blade is connected to the central shaft (210).

9. A propulsion device, characterized in that: include: A driving member (310); The propeller according to claim 8, connected to the driving member (310).

10. A ship, characterized in that: include: Hull(410) ； The power propulsion device as described in claim 9 is arranged on the hull (410).

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