Air film layer drag reduction device, method and ship based on porous super-hydrophobic material ventilation

Abstract

The application discloses a kind of based on porous super-hydrophobic material ventilation air film layer drag reduction device, method and ship, belong to air film drag reduction technical field;Device includes drag reduction component, gas supply module, data acquisition module and control module, drag reduction component includes porous super-hydrophobic plate and the non-porous material super-hydrophobic plate located downstream thereof;The porous super-hydrophobic plate is built-in with several air injection hole air passage, the air inlet of air passage is communicated with gas supply module, gas is ejected from air injection hole by air passage, then it is output to its outer wall surface by the small air hole of porous super-hydrophobic plate, and stable air film layer is formed by flowing through downstream non-porous material super-hydrophobic plate;Data acquisition module transmits collected data to control module, and control module judges whether air film meets requirements according to each data, and if not satisfied, corresponding gas supply amount is adjusted.The application solves the problem that uniform ventilation of the whole ship body is difficult to realize due to external water pressure in the prior art;Meanwhile, the injection rate is regulated.

Description

Technical Field

[0001] This invention belongs to the field of air film drag reduction technology, specifically relating to an air film drag reduction device, method, and ship based on porous superhydrophobic material for air passage. Background Technology

[0002] Water transport, primarily by ships, is the main mode of long-distance transportation. Historically, improving propulsion efficiency and conserving energy have been key objectives for ships. During navigation, ships encounter flow resistance, represented by frictional resistance and pressure drag, which increases fuel consumption. Reducing frictional resistance is a primary method for increasing ship speed and range while lowering energy consumption. Current main drag reduction methods include flexible walls, microbubbles, grooved surfaces, and hydrophobic surfaces.

[0003] Utilizing superhydrophobic surfaces in conjunction with artificial aeration can effectively reduce the contact area between the hull and water, replacing some of the slip surfaces with non-slip surfaces, thus producing a significant drag reduction effect. However, a crucial prerequisite for effective drag reduction is maintaining the gas film morphology of the superhydrophobic surface. Current technologies utilizing chemical reactions to generate gas include using aluminum sulfate and sodium bicarbonate to produce carbon dioxide gas that passes through micropores, forming a stable gas film on the hull bottom under the action of the superhydrophobic material. However, due to limitations in the amount of aluminum sulfate and sodium bicarbonate reactants, aeration stops once the reactants have completely reacted. Therefore, this method is only suitable for ships with relatively short ranges and high speeds, and is not conducive to stable and long-term drag reduction, thus having certain limitations. Existing technologies also disclose a drag-reducing device that uses a downstream jet of gas to generate drag. This device involves setting up a series of cascading cavities on the bottom of the ship, causing gas to remain in the cavities in the opposite direction of the ship's movement. This effectively reduces the frictional resistance of the ship's bottom surface. However, this method does not consider the curved surfaces of the hull and involves opening ventilation holes or slits on the bottom of the hull, which damages the hull structure. This significantly reduces the integrity of the hull surface and the strength of the bottom. Since the bottom is in constant contact with seawater, ventilation holes or slits can prevent the paint from completely covering the bottom, easily leading to corrosion and blockage.

[0004] Currently, most existing underwater air film drag reduction devices for ships are applied to the hull bottom, with limited research on drag reduction through ventilation on the curved surfaces of the hull side. Furthermore, under water pressure, it is difficult to achieve uniform ventilation across the entire hull. Therefore, it is necessary to design an underwater drag reduction device for ships based on porous superhydrophobic materials, and to implement a control method that regulates the jetting rate to maintain the stability of the air film layer on the hull surface. Summary of the Invention

[0005] The technical problem to be solved:

[0006] To overcome the shortcomings of existing technologies, this invention provides a drag-reducing device, method, and vessel based on a porous superhydrophobic material for air film layer ventilation. By embedding ventilation pipes with jet nozzles within a porous superhydrophobic stainless steel plate, the internal air pressure is increased, making it significantly greater than the seawater pressure difference across the hull's sides. In this case, the influence of the external seawater pressure difference can be ignored, thus achieving uniform ventilation across the hull's sides and bottom. This invention solves the problem in existing technologies where uniform ventilation across the entire hull is difficult due to external water pressure; it also enables the control of the jetting rate.

[0007] The technical solution of this invention is: a drag reduction device for an air film layer based on porous superhydrophobic materials, comprising a drag reduction component, an air supply module, a data acquisition module, and a control module.

[0008] The drag reduction component is attached to the surface to be drag-reduced, including a porous superhydrophobic plate and a non-porous superhydrophobic plate located downstream of it; the porous superhydrophobic plate has a built-in ventilation pipe with several jet holes, the air inlet of the ventilation pipe is connected to the air supply module, the gas is ejected from the jet holes through the ventilation pipe, and then output to its outer wall surface through the tiny pores of the porous superhydrophobic plate, and flows through the downstream non-porous superhydrophobic plate to form a stable gas film layer;

[0009] The data acquisition module transmits the acquired data to the control module. The control module determines whether the air membrane meets the requirements based on the data. If it does not meet the requirements, it adjusts the corresponding air supply.

[0010] A further technical solution of the present invention is as follows: the preparation method of the porous superhydrophobic plate is to loosely pack metal powder into a mold without pressing, embed a ventilation pipe with several air jet holes in the metal powder, and directly sinter it using a loose powder sintering method, relying on the capillary action and surface tension between powder particles during the sintering process to bond them together, thereby obtaining a porous superhydrophobic plate.

[0011] A further technical solution of the present invention is: the porous superhydrophobic plate is a porous superhydrophobic stainless steel plate, which includes multiple equally spaced pipes connected end to end to form an S-shaped ventilation pipe; the air jet holes of the ventilation pipe are located inside the porous superhydrophobic stainless steel plate and face its outer wall surface.

[0012] A further technical solution of the present invention is: the porous superhydrophobic stainless steel plate is obtained by superhydrophobic treatment of a porous breathable stainless steel plate, specifically as follows:

[0013] The porous stainless steel plate is pre-ground using a pre-grinding machine, and then laser marking machine is used to perform laser microstructure processing on the surface of the porous and breathable stainless steel plate.

[0014] Zinc silicate anti-rust paint and alkyl silicate curing agent are mixed evenly in a weight ratio of 4:1. The prepared anti-rust paint is then diluted with acetone and sprayed evenly onto the surface of the porous and breathable stainless steel plate using a spray gun.

[0015] Prepare epoxy resin solution, nano-SiO2 dispersion and low surface energy solution;

[0016] An epoxy resin solution is evenly coated onto a porous and breathable stainless steel surface and air-dried at room temperature. Then, it is immersed in a nano-SiO2 dispersion. After the surface dries, it is immersed in a low surface energy solution for low surface energy modification treatment to achieve a superhydrophobic effect.

[0017] A further technical solution of the present invention is: the non-porous material superhydrophobic plate is obtained by superhydrophobic treatment of non-porous material, that is, by spraying a superhydrophobic coating on the surface of non-porous material to achieve the superhydrophobic effect.

[0018] A further technical solution of the present invention is: the outer wall surface of the porous superhydrophobic plate and the non-porous superhydrophobic plate are both provided with equally spaced groove structures, and the grooves of the two are connected in sequence; and the air holes on the air passage of the porous superhydrophobic plate are opposite to the grooves.

[0019] A further technical solution of the present invention is: the data acquisition module includes a gas mass flow meter connected between the gas supply module and the air inlet of the porous superhydrophobic plate, a gas layer thickness measuring instrument, a pressure sensor and a friction sensor located on the surface to be drag-reduced; the gas mass flow meter is capable of measuring and controlling the gas flow rate.

[0020] A control method for a drag reduction device based on a porous superhydrophobic material-based air film layer includes the following steps:

[0021] The gas flow rate output by the gas supply module, as well as the gas layer thickness, pressure, and friction force on the surface to be dragged are obtained through the data acquisition module.

[0022] After receiving the data transmitted by the data acquisition module, the control module analyzes and judges the data, and issues a gas flow control command to the gas mass flow meter based on the result.

[0023] The gas mass flow meter executes the gas flow control command to complete the closed-loop control.

[0024] A ship includes a plurality of air film layer drag reduction devices based on porous superhydrophobic materials, which are equally spaced along the length of the ship from the bow. The porous superhydrophobic plates of the air film layer drag reduction devices are attached to the bottom and sides of the hull, and the non-porous superhydrophobic plates downstream of them are obtained by spraying a superhydrophobic coating on the outer surface of the hull.

[0025] A further technical solution of the present invention is that the air supply module of the air film layer drag reduction device is an air compressor installed inside the ship.

[0026] Beneficial effects

[0027] The beneficial effects of this invention are as follows:

[0028] 1. The present invention features a rational structural design. In the underwater air film drag reduction device for ships, gas permeates outward from the porous wall surface. This permeated gas not only alters the flow field density and viscosity near the wall but also changes the turbulent structure near the wall, thereby reducing frictional resistance. The hull surface is extensively covered by a superhydrophobic coating, which effectively reduces the adhesion of marine organisms to the stainless steel plates on the hull without compromising the integrity of the bottom anti-corrosion coating, slowing down corrosion and extending the service life of the hull and ventilation structure.

[0029] 2. Porous and breathable stainless steel sheets possess unique properties not typically found in other metals due to their special porous structure, such as breathability, heat dissipation, high strength, and corrosion resistance. Their porous structure also allows for lightweight and vibration-absorbing components, demonstrating excellent performance in applications such as air film drag reduction.

[0030] 3. The porous, breathable material has sufficient internal pressure to overcome the pressure difference between the upper and lower seawater on the sides of the hull. Drag-reducing components are installed on the hull to form multiple stable air films connected in series and running parallel. These components do not interfere with each other, ensuring the independence of the device. Attached Figure Description

[0031] Figure 1 A schematic diagram (front view) of the overall hull structure provided for this invention;

[0032] Figure 2 A cross-sectional view of the overall hull structure provided for this invention;

[0033] Figure 3 This is an enlarged schematic diagram of the drag reduction device module of the present invention;

[0034] Figure 4 This is a three-dimensional perspective view of the bottom structure of the hull of the present invention;

[0035] Figure 5 This is a schematic diagram of the drag reduction device at the bottom of the hull of the present invention;

[0036] Explanation of reference numerals in the attached drawings: 1. Porous superhydrophobic stainless steel plate, 2. Built-in ventilation pipe, 3. Non-porous superhydrophobic surface, 4. Detection and control center, 5. Gas mass flow meter, 6. Air compressor, 7. Valve, 8. Pressure sensor and friction sensor, 9. Jet nozzle, 10. Groove. Detailed Implementation

[0037] The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the invention, and should not be construed as limiting the invention.

[0038] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0039] In existing technologies, underwater air film drag reduction devices for ships struggle to achieve uniform gas permeation across the entire hull due to water pressure. This invention provides an air film drag reduction device and control method based on porous superhydrophobic materials. The device includes a drag reduction component, an air supply module, a data acquisition module, and a control module. The drag reduction component, attached to the surface to be drag-reduced, comprises a porous superhydrophobic plate and a downstream non-porous superhydrophobic plate. The porous superhydrophobic plate has a built-in air passage with several jet holes. The air inlet of the air passage is connected to the air supply module. Gas is ejected from the jet holes through the air passage, then output through the tiny pores of the porous superhydrophobic plate to its outer wall, flowing downstream to the non-porous superhydrophobic plate to form a stable air film layer. The data acquisition module transmits the collected data to the control module. The control module determines whether the air film meets the requirements based on the data; if not, it adjusts the corresponding air supply.

[0040] Specifically, the preparation method of the porous superhydrophobic plate is as follows: metal powder is loosely packed into a mold without being pressed, and a ventilation pipe with several air jet holes is buried in the metal powder. The loose powder sintering method is used to directly sinter the powder, and the powder particles are bonded together by capillary action and surface tension during the sintering process to obtain the porous superhydrophobic plate.

[0041] Specifically, the porous superhydrophobic plate is a porous superhydrophobic stainless steel plate, which includes multiple equally spaced pipes connected end to end to form an S-shaped ventilation pipe; the air jet holes of the ventilation pipe are located inside the porous superhydrophobic stainless steel plate and face its outer wall surface.

[0042] Specifically, the porous superhydrophobic stainless steel plate is obtained by treating a porous, breathable stainless steel plate with superhydrophobic properties. The specific method is as follows: the porous stainless steel plate is pre-ground using a pre-grinding machine, and a laser marking machine is used to perform laser microstructure processing on the surface of the porous, breathable stainless steel plate; zinc cinnamate anti-rust paint and alkyl cinnamate curing agent are mixed evenly in a weight ratio, and then the prepared anti-rust paint is diluted with acetone and evenly sprayed onto the surface of the porous, breathable stainless steel plate using a spray gun; an epoxy resin solution, a nano-SiO2 dispersion, and a low surface energy solution are prepared; the epoxy resin solution is evenly applied to the surface of the porous, breathable stainless steel plate, air-dried at room temperature, and then immersed in the nano-SiO2 dispersion. After the surface dries, it is immersed in the low surface energy solution for low surface energy modification treatment to achieve a superhydrophobic effect.

[0043] Specifically, the non-porous material superhydrophobic plate is obtained by treating a non-porous material with superhydrophobicity, that is, by spraying a superhydrophobic coating on the surface of the non-porous material to achieve the superhydrophobic effect.

[0044] Specifically, both the porous superhydrophobic plate and the non-porous superhydrophobic plate have equally spaced groove structures on their outer wall surfaces, and the grooves of the two are connected sequentially; and the air holes on the air passages of the porous superhydrophobic plate are opposite to the grooves.

[0045] Specifically, the data acquisition module includes a gas mass flow meter connected between the gas supply module and the air inlet of the porous superhydrophobic plate, a gas layer thickness measuring instrument, a pressure sensor, and a friction sensor located on the surface to be drag-reduced; the gas mass flow meter can measure and control the gas flow rate.

[0046] The control method for drag reduction of the air film layer based on porous superhydrophobic material air passage includes the following specific steps:

[0047] S1: Obtain the gas flow rate output by the gas supply module, the gas layer thickness, pressure, and friction force on the surface to be dragged down through the data acquisition module;

[0048] S2: After receiving the data transmitted by the data acquisition module, the control module analyzes and judges the data, and issues a gas flow control command to the gas mass flow meter based on the result.

[0049] S3: The gas mass flow meter executes the gas flow control command to complete the closed-loop control.

[0050] Applying the above technical solution to ships, the design principle is that when the gas pressure injected from the air jets inside the porous permeable material is much greater than the seawater pressure difference between the upper and lower sides of the hull, the influence of the seawater pressure difference outside the hull can be ignored, thus achieving uniform ventilation on the upper and lower sides of the hull and the bottom. The ship includes several air film layer drag reduction devices based on porous superhydrophobic materials, evenly spaced along the length of the ship from the bow. The porous superhydrophobic plates of these devices are attached to the bottom and sides of the hull. The downstream non-porous superhydrophobic plates are obtained by spraying a superhydrophobic coating onto the outer surface of the hull. The air supply module is an air compressor located inside the ship. After ventilation, a series of parallel drag-reducing air films are formed on the hull and bottom. To maintain the continuity of the air film, the porous permeable stainless steel plates and the non-porous material parts are treated with different superhydrophobic processes. Porous and breathable stainless steel plates are made superhydrophobic by laser microstructure processing and surface energy modification. For non-porous material parts, a superhydrophobic coating is directly sprayed onto the outer surface of the ship to achieve the same effect.

[0051] The above technical solution will be further explained below with reference to the accompanying drawings:

[0052] Reference Figure 1 As shown, the generating apparatus of this embodiment, based on an underwater drag reduction device using porous superhydrophobic materials, is applied to a ship. It includes multiple drag reduction devices spaced apart along the ship's length from the bow, forming a series of parallel drag-reducing air films on the hull and bottom. The drag reduction device consists of a data acquisition module, a control module, an air supply module, and drag reduction components. These components comprise a porous superhydrophobic stainless steel plate 1 and a non-porous superhydrophobic material surface 3. The drag reduction components are independent of each other and do not interfere with one another. To maintain the continuity of the air film, the porous permeable stainless steel plate and the non-porous material surface are treated with different superhydrophobic processes.

[0053] The porous, breathable stainless steel plate 1 is manufactured using a loose-pack powder sintering method, where metal powder is loosely packed into a mold without compression and sintered directly, relying on capillary action and surface tension between powder particles during the sintering process to bond them together. According to existing porous stainless steel plate manufacturing processes, an S-shaped ventilation pipe with a series of air jets is placed inside the porous, breathable stainless steel plate. The air jets are circular holes with a diameter of Q, and the spacing between the holes is 2-4 times the hole diameter. The air jets allow for high-speed gas ejection, resulting in an internal air pressure greater than the seawater pressure difference within the porous, breathable stainless steel plate. The air inlet of the built-in ventilation pipe is sequentially connected to an air supply module and a gas mass flow meter placed inside the ship. The air supply module includes an air compressor. The gas mass flow meter and air layer thickness measuring instrument in the data acquisition module constitute a ventilation injection rate control device. Pressure sensors, friction sensors, and the air layer thickness measuring instrument are distributed on the sides and bottom of the hull and connected to the receiving end of the detection and control module to collect frictional force and dynamic pressure field data of the hull wall and output them to the detection and control module.

[0054] Without compromising the structural strength of the hull, porous superhydrophobic stainless steel plates are bonded to the outer surface of the hull. Grooves are formed along the length of the hull at the bottom, and internal compressed ventilation pipes are arranged with jet nozzles along the width of the hull, positioned between the grooves. Gas is ejected from these nozzles through the internal ventilation pipes and then exits through the tiny pores of the porous superhydrophobic stainless steel plates onto the hull wall. In the non-porous material sections, a superhydrophobic coating is sprayed onto the hull wall and bottom. Under the action of this coating, multiple parallel stable air films are formed on the hull wall and bottom, covering the hull along its length. Based on data output from the detection and control module, the air mass flow meter is dynamically adjusted to achieve uniform distribution of the air film layer, thereby improving propulsion efficiency. Furthermore, due to the large area occupied by this device, this invention is applicable to medium- and high-speed large vessels.

[0055] For the superhydrophobic treatment of porous and breathable stainless steel plate 1, firstly, the porous stainless steel plate is pre-ground using a pre-grinding machine, and then laser microstructure processing is performed on the sample surface using a laser marking machine; secondly, zinc silicate anti-rust paint and alkyl silicate curing agent are mixed evenly in a weight ratio, and then the prepared anti-rust paint is diluted with acetone, and then evenly sprayed onto the sample surface using a spray gun; finally, epoxy resin solution, nano SiO2 dispersion and low surface energy solution are prepared; the epoxy resin solution is evenly coated on the porous stainless steel surface and air-dried at room temperature for 30 minutes; then it is immersed in nano SiO2 dispersion, kept at 100℃ in a drying oven for 5 hours, and after the surface is dried, it is immersed in low surface energy solution for low surface energy modification treatment to achieve superhydrophobic effect.

[0056] For non-porous material parts, a superhydrophobic coating is directly sprayed onto the outer surface of the hull to achieve a superhydrophobic effect.

[0057] Reference Figure 2 As shown, it is a cross-sectional view of the overall hull structure. Without compromising the strength of the hull, a series of porous superhydrophobic stainless steel plates 1 with built-in ventilation pipes 2 are installed on the hull wall and bottom. The diameter of the air jet is Q. The spacing between the holes distributed along the depth direction on the curved surface of the hull side is 4Q. The inner surface of the porous superhydrophobic stainless steel plate is tangent to the outer surface of the hull.

[0058] like Figure 3The diagram shown is an enlarged schematic of the drag reduction device module of the present invention. The gas mass flow meter and the gas supply module are fixedly installed inside the ship via support components. The gas supply module includes multiple sets of gas supply components spaced apart along the ship's length, consisting of an air compressor 6. The gas mass flow meter 5 is connected to the air inlet of the built-in ventilation pipe 2 with a valve 7. Pressure sensors and friction sensors 8 are evenly distributed on the sides and bottom of the ship's hull and connected to the control center. They are used to detect and output data to the detection control center 4. Based on the detected data, the center determines whether the gas film is uniform. If it is not uniform, it controls the gas mass flow meter 5 at the corresponding position in the gas supply pipe to adjust the ventilation rate of the corresponding pipe section. Under different incoming flow velocities, the ventilation rate is dynamically adjusted according to the morphology of the gas film layer on the ship's surface to maintain the stability of the gas film layer on the ship's surface and achieve uniform gas ventilation.

[0059] Reference Figure 4 , Figure 5 The diagram shows an enlarged schematic of the porous stainless steel plate at the bottom of the hull. The porous superhydrophobic stainless steel plate and the non-porous superhydrophobic surface at the bottom of the ship have several grooves 10 aligned with the forward direction. Gas enters the grooves 10 through vents 9, allowing the ejected airflow to cover the bottom of the hull along its length. By injecting gas into the inner vent pipe 2, the gas spreads evenly through the porous material, forming multiple parallel stable gas films on the sides and bottom grooves of the hull along the opposite direction of the ship's movement, under the action of the non-porous superhydrophobic surface 3 at the rear. These gas films adhere to the sides and bottom of the hull, contacting the seawater and reducing friction on the hull surface.

[0060] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A drag reduction device for an air film layer based on porous superhydrophobic materials, characterized in that: Includes drag reduction components, air supply module, data acquisition module, and control module. The drag reduction component is attached to the surface to be drag-reduced, including a porous superhydrophobic plate and a non-porous superhydrophobic plate located downstream of it; the porous superhydrophobic plate has a built-in ventilation pipe with several jet holes, the air inlet of the ventilation pipe is connected to the air supply module, the gas is ejected from the jet holes through the ventilation pipe, and then output to its outer wall surface through the tiny pores of the porous superhydrophobic plate, and flows through the downstream non-porous superhydrophobic plate to form a stable gas film layer; The data acquisition module transmits the acquired data to the control module. The control module determines whether the air membrane meets the requirements based on the data. If it does not meet the requirements, it adjusts the corresponding air supply. The porous superhydrophobic plate is prepared by loosely loading metal powder into a mold without pressing, embedding a ventilation pipe with several air jet holes in the metal powder, and directly sintering it using a loose powder sintering method. The powder particles are bonded together by capillary action and surface tension during the sintering process to obtain the porous superhydrophobic plate.

2. The drag reduction device for air film layer based on porous superhydrophobic material ventilation according to claim 1, characterized in that: The porous superhydrophobic plate is a porous superhydrophobic stainless steel plate, which includes multiple equally spaced pipes connected end to end to form an S-shaped ventilation pipe; the air jet holes of the ventilation pipe are located inside the porous superhydrophobic stainless steel plate and face its outer wall surface.

3. The drag reduction device for air film layer based on porous superhydrophobic material ventilation according to claim 2, characterized in that: The porous superhydrophobic stainless steel plate is obtained by treating a porous, breathable stainless steel plate with superhydrophobic properties. The specific method is as follows: The porous stainless steel plate is pre-ground using a pre-grinding machine, and then laser marking machine is used to perform laser microstructure processing on the surface of the porous and breathable stainless steel plate. Zinc silicate anti-rust paint and alkyl silicate curing agent are mixed evenly at a weight ratio of 4:

1. The prepared anti-rust paint is then diluted with acetone and sprayed evenly onto the surface of the porous and breathable stainless steel plate using a spray gun. Prepare epoxy resin solution, nano-SiO2 dispersion and low surface energy solution; An epoxy resin solution is evenly coated onto a porous and breathable stainless steel surface and air-dried at room temperature. Then, it is immersed in a nano-SiO2 dispersion. After the surface dries, it is immersed in a low surface energy solution for low surface energy modification treatment to achieve a superhydrophobic effect.

4. The drag reduction device for air film layer based on porous superhydrophobic material ventilation according to claim 1, characterized in that: The non-porous material superhydrophobic plate is obtained by treating the non-porous material with superhydrophobicity, that is, by spraying a superhydrophobic coating on the surface of the non-porous material to achieve the superhydrophobic effect.

5. The drag reduction device for air film layer based on porous superhydrophobic material ventilation according to claim 1, characterized in that: Both the porous superhydrophobic plate and the non-porous superhydrophobic plate have equally spaced groove structures on their outer wall surfaces, and the grooves of the two are connected sequentially; and the air holes on the air vents of the porous superhydrophobic plate are opposite to the grooves.

6. The drag reduction device for air film layer based on porous superhydrophobic material ventilation according to claim 1, characterized in that: The data acquisition module includes a gas mass flow meter connected between the gas supply module and the air inlet of the porous superhydrophobic plate, a gas layer thickness measuring instrument, a pressure sensor, and a friction sensor located on the surface to be drag-reduced; the gas mass flow meter can measure and control the gas flow rate.

7. A control method for a drag reduction device based on porous superhydrophobic material for air film layer as described in any one of claims 1-6, characterized in that... The specific steps are as follows: The gas flow rate output by the gas supply module, as well as the gas layer thickness, pressure, and friction force on the surface to be dragged are obtained through the data acquisition module. After receiving the data transmitted by the data acquisition module, the control module analyzes and judges the data, and issues a gas flow control command to the gas mass flow meter based on the result. The gas mass flow meter executes the gas flow control command to complete the closed-loop control.

8. A ship, characterized in that: The device includes several air film layer drag reduction devices based on porous superhydrophobic materials, as described in any one of claims 1-6, which are arranged at equal intervals along the length of the ship from the bow. The porous superhydrophobic plate of the air film layer drag reduction device is attached to the bottom and side surfaces of the hull, and the downstream non-porous superhydrophobic plate is obtained by spraying a superhydrophobic coating on the outer surface of the hull.

9. A ship according to claim 8, characterized in that: The air supply module of the air film layer drag reduction device is an air compressor installed inside the ship.

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