A type of superhydrophobic leaf of the sedge species

Abstract

This invention belongs to the field of fluid machinery technology, and particularly relates to a superhydrophobic blade of the *Carex trispora* type, comprising: a hub and several blades fixed to the hub; the blade surface is provided with a leaf vein-like configuration, which is a grooved structure that divides the blade into multiple regions, each region containing several cell-like protrusions; a hydrophobic layer is coated on the blade surface. Compared with traditional technologies, this invention, by simulating the hydrophobic blade structure of *Carex trispora*, endows the blade with superhydrophobicity, thereby improving the blade's self-cleaning ability.

Description

Technical Field

[0001] This invention belongs to the field of fluid machinery technology, and in particular relates to a three-spike sedge-shaped superhydrophobic blade. Background Technology

[0002] Many plant leaves in nature exhibit superhydrophobicity, such as lotus leaves and peanut leaves. The surface structure and chemical composition of these leaves are key factors in achieving superhydrophobic properties. The surface microstructure of *Carex trisporium* leaves mainly exhibits typical structural morphologies such as a single-layer convex hull type and a reticulated hollow type. These special surface structures provide physical roughness to the leaves, increasing the contact angle when droplets come into contact with the surface, thereby enhancing the hydrophobicity of the leaves. Furthermore, the surface of *Carex trisporium* leaves contains waxes, which form a protective film on the surface, further increasing the hydrophobicity of the leaves.

[0003] In existing blades, the friction between the fluid and the blade is relatively high, which reduces the operating efficiency of the machinery. To address this, we provide a blade with a superhydrophobic surface to reduce solid-liquid adhesion forces, while also reducing the adhesion of dirt and deposits, thereby improving the performance and reliability of fluid machinery during operation. Summary of the Invention

[0004] The purpose of this invention is to provide a superhydrophobic leaf of the *Carex triflora* type to solve the above-mentioned problems.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] A superhydrophobic blade of the sedge-shaped type includes a hub and several blades fixed to the hub. The surface of the blade is provided with a leaf vein-like configuration. The leaf vein-like configuration is a slotted structure. The leaf vein-like configuration divides the blade into multiple regions. Several cell-like protrusion configurations are arranged in the regions.

[0007] The blade surface is coated with a hydrophobic layer.

[0008] Optionally, the leaf-like vein configuration includes:

[0009] A longitudinal groove, the longitudinal groove being located along the centerline of the blade;

[0010] Several sets of oblique transverse groove components are spaced apart along the length direction of the longitudinal groove. Each oblique transverse groove component includes two oblique transverse grooves, which are symmetrically arranged about the longitudinal groove.

[0011] The longitudinal groove is connected to the oblique transverse groove; the longitudinal groove and the oblique transverse groove are at an angle;

[0012] The longitudinal groove and the oblique transverse groove have the same structure.

[0013] Optionally, the cell-like protrusion configuration is a trapezoidal frustum structure, and the bottom and top surfaces of the cell-like protrusion configuration are both square structures, with the bottom side length a being greater than the top side length b.

[0014] Optionally, the hydrophobic layer includes a surface hydrophobic gel coating applied to the surface of the blade.

[0015] Optionally, the surface hydrophobic gel coating has a thickness of 120 μm.

[0016] Optionally, the spacing Y between two adjacent cell-like protrusion configurations along the longitudinal groove direction is:

[0017] ΔY = k2·a;

[0018] Where 1.5≤k2≤3.

[0019] Optionally, the spacing ΔX between two adjacent cell-like protrusion configurations along the direction perpendicular to the longitudinal groove is:

[0020] ΔX = k1·a;

[0021] Where 1.5≤k1≤3.

[0022] Optionally, the side length 'a' of the square base of the cell-like protrusion configuration is:

[0023] a = k3·d1;

[0024] Where: 0.02≤k3≤0.1;

[0025] The side length b of the square on the top surface of the cell-like protrusion configuration is:

[0026] b = k4·a;

[0027] Where: 0.7≤k4≤0.95;

[0028] The base angle θ of the trapezoidal side of the cell-like protrusion configuration is in the range of 10°≤θ≤45°;

[0029] The protrusion height h of the cell-like protrusion configuration is:

[0030] h = k5·a;

[0031] Where 0.05 ≤ k5 ≤ 0.3;

[0032] Where d1 is the diameter of the leaf root of leaf 2, and d2 is the diameter of the leaf tip of leaf 2.

[0033] Optional,

[0034] The groove depth ΔZ of the blade-like vein configuration is:

[0035] ΔZ = k6·a;

[0036] Where 0.1≤k6≤0.3.

[0037] Optionally, the longitudinal groove and the oblique transverse groove are provided with an arc transition surface at the connection with the blade surface.

[0038] Compared with the prior art, the present invention has the following advantages and technical effects:

[0039] The present invention relates to a superhydrophobic blade in the form of a three-spike sedge, comprising a hub and several blades disposed on the hub. The blade surface is provided with a cellular protrusion configuration mimicking the three-spike sedge and a vein configuration mimicking leaf veins, and a hydrophobic layer is uniformly coated on the blade surface. Compared to traditional technologies, this invention imparts superhydrophobicity to the blade by simulating the hydrophobic leaf structure of a three-spike sedge, thereby improving the blade's self-cleaning ability. Water droplets on the blade surface form spheres and roll rapidly, carrying away dust and impurities, keeping the blade surface clean. The blade surface repels water and oily substances, preventing the adhesion of microorganisms, dirt, and corrosive substances, thus extending the blade's service life. The self-cleaning and anti-fouling properties of the blade reduce dependence on chemical cleaning agents, while its low water resistance and anti-corrosion properties also reduce energy consumption, exhibiting significant environmental advantages. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a front view of the leaf of the invention, which resembles the shape of a three-spike sedge.

[0042] Figure 2 This is a partial schematic diagram of the surface of the leaf of the invention, which imitates the shape of a three-spike sedge.

[0043] Figure 3 This is a schematic diagram illustrating the vein-like dimensions of the leaf of the invention, which mimics the shape of a three-spike sedge.

[0044] Figure 4 This is a schematic diagram of the cross-sectional dimensions of the imitation vein-shaped leaf of the present invention, which is modeled after the three-spike sedge.

[0045] Figure 5 This is a schematic diagram showing the size of the imitation cell protrusions on the leaf of the Scirpus triflorus plant of the present invention;

[0046] Figure 6 This is a schematic diagram of the hydrophobic gel coating on the blade surface of the present invention;

[0047] Figure 7 These are schematic diagrams illustrating different application scenarios of the present invention;

[0048] Among them, 1. hub; 2. blade; 3. cell-like protrusion configuration; 4. blade-like vein configuration; 5. surface hydrophobic gel coating. Detailed Implementation

[0049] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0051] Reference Figures 1 to 7 The present invention discloses a three-spike sedge-type superhydrophobic leaf, including a hub 1 and several blades 2 fixed on the hub 1. The surface of the blade 2 is provided with a leaf vein-like structure 4. The leaf vein-like structure 4 is a slotted structure. The leaf vein-like structure 4 divides the blade 2 into multiple regions, and several cell-like protrusion structures 3 are arranged in the regions.

[0052] The surface of blade 2 is coated with a hydrophobic layer.

[0053] The present invention relates to a superhydrophobic blade in the form of a three-spike sedge, comprising a hub 1 and a plurality of blades 2 disposed on the hub 1. The surface of the blades 2 is provided with a three-spike sedge-shaped cell-like protrusion configuration 3 and a leaf-like vein configuration 4, and a hydrophobic layer is uniformly coated on the surface of the blades 2. Compared with traditional technologies, the present invention, by simulating the hydrophobic leaf structure of a three-spike sedge, endows the blades 2 with superhydrophobicity, thereby improving the self-cleaning ability of the blades 2. Water droplets on the surface of the blades 2 form spheres and roll rapidly, carrying away dust and impurities, keeping the surface of the blades 2 clean. The surface of the blades 2 can repel water and oily substances, preventing the adhesion of microorganisms, dirt, and corrosive substances, thereby extending the service life of the blades 2. The self-cleaning and anti-fouling properties of the blades 2 reduce the dependence on chemical cleaning agents, while their low water resistance and anti-corrosion performance also reduce energy consumption, exhibiting significant environmental advantages.

[0054] As an optional implementation, the hydrophobic layer includes a surface hydrophobic gel coating 5, which is applied to the surface of the blade 2.

[0055] As an optional implementation, the surface hydrophobic gel coating 5 has a thickness of 120 μm.

[0056] When using a surface hydrophobic gel coating 5 to ensure hydrophobicity on the surface of the mechanical blade 2, the coating thickness is a crucial parameter. The thickness of the surface hydrophobic gel coating 5 in this invention is approximately 120 μm. (μm: micrometer) This thickness range provides excellent superhydrophobic properties, resulting in a smooth, continuous, and dense coating surface with low surface energy and a micro / nano-scale structure, conforming to the Cassie-Baxter model. Simultaneously, the coating exhibits a contact angle (WCA) of 167.2 degrees and a sliding angle (SA) of 2.2 degrees, demonstrating superior superhydrophobicity.

[0057] As an optional implementation, the leaf-like vein configuration 4 includes:

[0058] Longitudinal groove, the longitudinal groove is located on the centerline of blade 2;

[0059] Several sets of oblique transverse groove components are spaced apart along the longitudinal groove length direction. Each oblique transverse groove component includes two oblique transverse grooves, which are symmetrically arranged about the longitudinal groove.

[0060] The longitudinal groove is connected to the oblique transverse groove; the longitudinal groove and the oblique transverse groove are at an included angle;

[0061] The longitudinal groove and the oblique transverse groove have the same structure.

[0062] As an optional implementation, the cell-like protrusion configuration 3 is a trapezoidal truncated structure. The bottom and top surfaces of the cell-like protrusion configuration 3 are both square structures, and the side length a of the bottom surface of the cell-like protrusion configuration 3 is greater than the side length b of the top surface of the cell-like protrusion configuration 3.

[0063] The basic shape of the cell-like protrusion configuration 3 is a protruding trapezoidal column structure, with the top and bottom surfaces being squares of unequal area. The four sides of the cell-like protrusion configuration 3 are trapezoidal, with the top and bottom sides of the trapezoids being the side lengths of the top and bottom squares. This ensures that the sides have an inclined angle, reducing the impact loss of the incoming flow.

[0064] The basic shape of the blade-like vein configuration 4 is a symmetrical elongated groove, including a longitudinal groove and several sets of symmetrical oblique transverse grooves. The edges of the grooves and the blade surface are connected by rounded corners. Each groove includes two symmetrical groove surfaces that are connected at a certain angle. At the connection between the longitudinal groove and the oblique transverse grooves, there is also a specific angle range between the groove surfaces.

[0065] Several cell-like protrusion configurations 3 are systematically distributed along the fluid streamline direction on the surface of the leaf 2 according to a certain arrangement rule, mainly covering the pressure surface and suction surface of the leaf 2, and distributed as needed on the leaf tip surface.

[0066] The cell-like protrusion configuration 3 is arranged at different diameter positions on the leaf according to a specific length, and its distribution range covers 30% to 95% of the chord length of the leaf 2.

[0067] As an optional implementation, the spacing ΔY between two adjacent cell-like protrusion configurations 3 along the longitudinal groove direction is:

[0068] ΔY = k2·a;

[0069] Where 1.5≤k2≤3.

[0070] As an optional implementation, the distance ΔX between two adjacent cell-like protrusion configurations 3 along the direction perpendicular to the longitudinal groove is:

[0071] ΔX = k1·a;

[0072] Where 1.5≤k1≤3.

[0073] As an optional implementation, the side length 'a' of the square base of the cell-like protrusion configuration 3 is:

[0074] a = k3·d1;

[0075] Where: 0.02≤k3≤0.1;

[0076] The side length b of the square on the top surface of the cell-like protrusion configuration 3 is:

[0077] b = k4·a;

[0078] Where: 0.7≤k4≤0.95;

[0079] The base angle θ of the trapezoidal side of the cell protrusion configuration 3 is in the range of 10°≤θ≤45°;

[0080] The protrusion height h of the cell-like protrusion configuration 3 is:

[0081] h = k5·a;

[0082] Where 0.05 ≤ k5 ≤ 0.3;

[0083] Where d1 is the diameter of the leaf root of leaf 2, and d2 is the diameter of the leaf tip of leaf 2.

[0084] The specific parameters of the cell-like protrusion configuration 3 include: the side length a of the base square, the side length b of the top square, the base angle θ of the side trapezoid, and the protrusion height h. The arrangement parameters of several cell-like protrusion configurations 3 include a lateral spacing of ΔX perpendicular to the streamline direction and a longitudinal spacing of ΔY along the streamline direction.

[0085] The side length 'a' of the base square is a given value.

[0086] When designing the above superhydrophobic configurations, the determination of their geometric parameters needs to be based on the characteristics of the fluid medium and the specific operating conditions. The following is a detailed introduction to the values ​​of each parameter.

[0087] Several cell-like protrusion configurations 3 are usually arranged in a system. The lateral spacing ΔX and the longitudinal spacing ΔY between the configurations are among the key design parameters that affect their hydrophobic effect.

[0088] To adjust the distribution range to meet the needs of different working conditions, the lateral spacing between the three cell-like protrusion configurations is: ΔX = k1·a, where: k1 is a proportionality coefficient, generally taken as 1.5 ≤ k1 ≤ 3, to meet its distribution range. a is the side length of the square base of the cell-like protrusion configuration 3.

[0089] The longitudinal spacing between the three cell-like protrusion configurations is: ΔY = k2·a, where k2 is a proportionality coefficient, generally taken as 1.5 ≤ k2 ≤ 3 to satisfy its distribution range. a is the side length of the square base of the cell-like protrusion configuration 3.

[0090] The cell-like protrusion configuration 3 is a three-dimensional trapezoidal pedestal structure, which is preferentially set in the region from hub 1 to disk. Its distribution range is between 1.2d1 and 0.9d2, where d1 is the root diameter of leaf 2 and d2 is the tip diameter of leaf 2.

[0091] To meet the distribution density requirements, the side length a of the square base of the cell-like protrusion configuration 3 satisfies: a = k3·d1, where k3 is a proportionality coefficient, generally taken as 0.02≤k3≤0.1 to meet its distribution density.

[0092] To avoid excessive airflow resistance, the side length b of the square on the top surface of the cell-like protrusion configuration 3 satisfies: b = k4·a, where k4 is a proportionality coefficient, generally taken as 0.7 ≤ k4 ≤ 0.95. The base angle θ of the side trapezoid is usually between 10 degrees and 45 degrees. The protrusion height h satisfies: h = k5·a, where k5 is a proportionality coefficient, generally taken as 0.05 ≤ k5 ≤ 0.3.

[0093] As an optional implementation method,

[0094] The groove depth ΔZ of the leaf-like vein configuration 4 is:

[0095] ΔZ = k6·a;

[0096] Where 0.1≤k6≤0.3.

[0097] As an optional implementation, the longitudinal groove and the oblique transverse groove are provided with an arc transition surface at the connection with the surface of the blade 2.

[0098] The specific parameters of the blade-like vein configuration 4 include: vein depth ΔZ, chord length of the rounded corner at the junction of the groove edge and the blade surface ΔW, and angles α (absolute velocity angle) and β (flow angle) at the junction of the longitudinal and transverse veins.

[0099] The intersecting vein-like configuration 4 of blade 2 presents a grid-like structure similar to the veins of a three-spike sedge leaf, composed of multiple intersecting lines forming several small areas. These lines form a supporting framework on the blade surface. In the vein-like configuration 4, ΔZ represents the vein depth along the height direction of blade 2. The magnitude of the vein depth ΔZ has a significant impact on the aerodynamic performance and structural strength of blade 2. ΔZ can be expressed as a certain proportion of the thickness (t) of blade 2, satisfying: ΔZ=k6·a where: k6 is a proportionality coefficient, generally taken as 0.1≤k6≤0.3, depending on the application scenario and design requirements of blade 2.

[0100] As an optional implementation, the rounded chord length of the arc transition surface at the junction of the longitudinal groove and the oblique transverse groove with the surface of blade 2 is ΔW, and the range of values ​​for ΔW is:

[0101] 1mm≤ΔW≤10mm.

[0102] The rounded chord length design makes the blade surface smoother, reducing fluid turbulence and separation on the blade surface. Generally, 1mm ≤ ΔW ≤ 10mm (mm: millimeter). The specific value of the rounded chord length needs to be comprehensively considered and optimized based on factors such as the actual application scenario of the blade, fluid properties, and design objectives.

[0103] The angles α (absolute velocity angle) and β (flow angle) at the connection between the longitudinal and transverse grooves of the blade-like vein configuration 4 are suggested angle parameters.

[0104] As an additional implementation, the angle between the bottom edge of the transverse groove and the inclined edge of the longitudinal groove is α, and the formula for calculating α is:

[0105]

[0106] Among them, V m It is the axial velocity, V u It is the circumferential velocity.

[0107] As an additional implementation, the angle between the bottom edge of the longitudinal groove and the inclined edge of the transverse groove is β, and the formula for calculating β is:

[0108]

[0109] Where, ω m It is the axial component of the relative velocity, ω uIt is the circumferential component of the relative velocity.

[0110] The angle α (absolute velocity angle) can be calculated using the velocity triangle, with the formula: Among them, V m It is the axial velocity, V u It is the circumferential velocity.

[0111] The angle β (flow angle) can also be calculated using the velocity triangle, with the formula: Where, ω m It is the axial component of the relative velocity, ω u It is the circumferential component of the relative velocity.

[0112] The angle α (absolute velocity angle) is typically between 10 and 45 degrees, depending on the position of the blade 2 and the flow characteristics of the fluid. At the impeller inlet, α is smaller, ranging from 10 to 20 degrees; while at the impeller outlet, α is larger, ranging from 20 to 45 degrees. The angle β (flow angle) generally ranges from 20 to 60 degrees. For some blade designs requiring high efficiency, β is between 20 and 30 degrees; while for blade designs requiring larger flow rates, β is between 30 and 60 degrees.

[0113] The edges of the sedge-like cell protrusions on the leaf surface are beveled, and the edges of the grooves are rounded at the junction with the leaf surface, thus reducing water resistance. This characteristic allows the leaf to maintain good performance under deep water or fluid impact conditions, and also reduces energy consumption.

[0114] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0115] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A three-spike sedge-shaped superhydrophobic blade, comprising a hub (1) and a plurality of blades (2) fixedly attached to the hub (1), characterized in that, The surface of the blade (2) is provided with a leaf vein pattern (4), which is a slotted structure. The leaf vein pattern (4) divides the blade (2) into multiple regions, and a number of cell protrusion patterns (3) are arranged in the regions. The blade (2) has a hydrophobic coating on its surface.

2. The superhydrophobic leaf of the *Carex trisporoides* type according to claim 1, characterized in that, The leaf-like vein configuration (4) includes: A longitudinal groove, the longitudinal groove being located on the centerline of the blade (2); Several sets of oblique transverse groove components are spaced apart along the length direction of the longitudinal groove. Each oblique transverse groove component includes two oblique transverse grooves, which are symmetrically arranged about the longitudinal groove. The longitudinal groove is connected to the oblique transverse groove; the longitudinal groove and the oblique transverse groove are at an angle; The longitudinal groove and the oblique transverse groove have the same structure.

3. The superhydrophobic leaf of the *Carex trisporoides* type according to claim 1, characterized in that: The cell-like protrusion configuration (3) is a trapezoidal truncated structure. The bottom and top surfaces of the cell-like protrusion configuration (3) are both square structures. The side length a of the bottom surface of the cell-like protrusion configuration (3) is greater than the side length b of the top surface of the cell-like protrusion configuration (3).

4. The superhydrophobic leaf of the *Carex trisporoides* type according to claim 1, characterized in that: The hydrophobic layer includes a surface hydrophobic gel coating (5), which is applied to the surface of the blade (2).

5. A superhydrophobic leaf of the *Carex trisporoides* type according to claim 4, characterized in that: The surface hydrophobic gel coating (5) has a thickness of 120 μm.

6. The superhydrophobic leaf of the *Carex trisporoides* type according to claim 2, characterized in that, The distance ΔY between two adjacent cell-like protrusion configurations (3) along the longitudinal groove direction is: ΔY = k2·a; Where 1.5≤k2≤3.

7. A superhydrophobic leaf of the *Carex trisporoides* type according to claim 2, characterized in that: The distance ΔX between two adjacent cell-like protrusion configurations (3) along the direction perpendicular to the longitudinal groove is: ΔX = k1·a; Where 1.5≤k1≤3.

8. A three-spike sedge-type superhydrophobic leaf according to claim 1, characterized in that, The side length a of the square base of the cell-like protrusion configuration (3) is: a = k3·d1; Where: 0.02≤k3≤0.1; The side length b of the square on the top surface of the cell-like protrusion configuration (3) is: b = k4·a; Where: 0.7≤k4≤0.95; The base angle θ of the side trapezoid of the simulated cell protrusion configuration (3) is in the range of 10°≤θ≤45°; The protrusion height h of the cell-like protrusion configuration (3) is: h = k5·a; Where 0.05 ≤ k5 ≤ 0.3; Where d1 is the root diameter of the leaf (2) and d2 is the tip diameter of the leaf (2).

9. A superhydrophobic leaf of the *Carex trisporoides* type according to claim 1, characterized in that: The groove depth ΔZ of the simulated leaf vein configuration (4) is: ΔZ = k6·a; Where 0.1≤k6≤0.

3.

10. A superhydrophobic leaf of the *Carex trisporoides* type according to claim 2, characterized in that: The longitudinal groove and the oblique transverse groove are provided with an arc transition surface at the connection with the surface of the blade (2).

Images