A bionic drag reduction system for underwater vehicles based on the penetration of drag reducers

Abstract

The present invention belongs to the technical field of hydrodynamic drag reduction, and discloses a bionic drag reduction system for underwater navigation bodies based on the infiltration of drag reducers, including a non-powered charging mechanism and a drag reducer bionic injection mechanism, wherein the non-powered charging mechanism includes a water inlet opening, a water inlet channel, a movable cover plate, an air storage cavity, and a one-way guide Tesla valve, and the drag reducer bionic injection mechanism includes a grid support body, a grid channel, a double-layer elastic membrane, an elastic stay, and a micro-groove. When the underwater navigation body is in a static state underwater, the movable cover plate is tightly closed under the action of the gas inside the air storage cavity, at which time the gas inside the air storage cavity will not enter the double-layer elastic membrane, and the elastic stay is in a closed state; when the underwater navigation body is in a forward state, the movable cover plate is opened under the influence of the water flow pressure, and the gas inside the air storage cavity enters the double-layer elastic membrane through the one-way guide Tesla valve for pressurization, and the drag reduction liquid overflows to the outside through the elastic stay. The present invention can be applied to the field of outflow flow to adapt to different operating conditions and effectively reduce flow resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrodynamic drag reduction, and in particular, relates to a bionic drag reduction system for an underwater vehicle based on the infiltration of a drag reducer. Background Art

[0002] When a ship or underwater vehicle moves, the resistance it encounters is mainly composed of the friction resistance of the interaction between the surface of the vehicle and the surrounding water flow and the pressure difference resistance before and after the vehicle. This resistance is the main way for the vehicle to consume energy. Using drag reduction technology to reduce the driving resistance of the vehicle can not only improve energy conversion efficiency and reduce energy transmission costs, but also reduce noise and improve the stealth performance of the vehicle.

[0003] From the perspective of hydrodynamics, the reason why fish have extraordinary movement ability is essentially based on flow control technology, that is, fish can effectively control the changes in the spatiotemporal structure of the external water flow field according to the characteristics of the external flow field through the special structure of the fish body surface and fins, flexible deformation, and even release certain substances and energy to the outward flow. The substance released to the external flow field is usually mucus secreted from the surface of the fish body. This type of mucus has significant rheological properties and is a non-Newtonian fluid. It can be considered that this secreted mucus produces a turbulent drag reduction effect. From the perspective of drag reduction, fish surface drag reduction is a turbulent drag reduction in the form of external flow. From the perspective of the scope of influence, most of the surface is in the boundary layer, which is a form of boundary layer turbulent drag reduction.

[0004] The current drag reduction methods generally have problems such as difficulty in implementation, large volume, rotating moving parts, and complex operation. Since friction resistance is mainly determined by factors such as surface state, wet surface area, fluid viscosity coefficient and flow structure characteristics, a bionic drag reduction system can be proposed based on the drag reduction flow mechanism of low-drag fish. Summary of the invention

[0005] The present invention aims to improve the phenomenon of large resistance and high energy consumption in wall-constrained flow, and to solve the problems of difficult implementation, complicated operation and poor effect of existing drag reduction methods. A bionic drag reduction system for underwater vehicles based on the infiltration of drag reducers is proposed. Its application in the field of outflow flow can adapt to different operating conditions and effectively reduce flow resistance.

[0006] In order to achieve the above-mentioned object of the invention, the present invention is implemented by the following technical solutions:

[0007] The present invention provides a bionic drag reduction system for an underwater vehicle based on the infiltration of a drag reducer, comprising a non-powered charging mechanism and a bionic drag reducer injection mechanism;

[0008] The unpowered charging mechanism includes a plurality of water inlet channels arranged in the head section of the underwater vehicle, each of which extends in a straight line along the length direction of the underwater vehicle, with its front end sealedly connected to the water inlet opening and its rear end sealedly connected to the air storage chamber; a plurality of water inlet openings are arranged on the surface of the head section of the underwater vehicle, for realizing the connection between the outside of the underwater vehicle and the water inlet channel; a movable cover is arranged at the connection between each of the water inlet channels and the air storage chamber, and the movable cover can completely cover the water inlet channel in a closed state and can rotate toward the air storage chamber in an open state; the air storage chamber is located at the connection between the head section and the middle section of the underwater vehicle, and the interior of the air storage chamber is pre-filled with gas of a certain pressure; the air storage chamber is connected to the interior of the double-layer elastic membrane of the drag reducer bionic injection mechanism through a one-way conduction Tesla valve;

[0009] The drag reducing agent bionic injection mechanism comprises a double-layer elastic membrane covering the outer wall surface of the middle section of the underwater vehicle, a closed chamber is formed between the upper membrane surface and the lower membrane surface of the double-layer elastic membrane, and the drag reducing liquid is stored in the chamber; the lower membrane surface of the double-layer elastic membrane is tightly fitted and installed with the outer wall surface of the underwater vehicle, and the inner surface of the upper membrane surface of the double-layer elastic membrane is provided with a grid channel, and the grid channel is supported by a grid support body; the upper membrane surface of the double-layer elastic membrane covers the lower membrane surface in a natural state, and the double-layer elastic membrane is filled with After compression, the upper membrane surface bulges to expand the volume of the chamber; the upper membrane surface of the double-layer elastic membrane is provided with a plurality of seepage holes, the seepage holes are evenly distributed on the permeable surface, and are covered by an elastic stretcher with the same shape as the seepage holes; the elastic stretcher is made of the same material as the double-layer elastic membrane; the front end of the elastic stretcher is rotatably connected to the upper membrane surface of the double-layer elastic membrane, so that the elastic stretcher can be opened outward; the surface of the elastic stretcher is provided with a plurality of ridge-like protrusions, each of which extends along the length direction of the underwater navigation body to form micro grooves on the surface of the elastic stretcher;

[0010] When the underwater vehicle is in a stationary state underwater, the movable cover plate is pressed against the rear end of the water inlet channel under the action of the gas inside the air storage chamber. At this time, the gas inside the air storage chamber will not enter the double-layer elastic membrane, and thus the elastic support block is in a closed state; when the underwater vehicle is in a forward state, water flows into the water inlet channel through the water inlet opening, and the movable cover plate is opened due to the influence of the water flow pressure, thereby allowing the water flow to enter the air storage chamber, and then the gas inside the air storage chamber enters the double-layer elastic membrane through the unidirectional Tesla valve to pressurize the double-layer elastic membrane. At this time, the drag reducing liquid inside the double-layer elastic membrane overflows to the outside through the elastic support block.

[0011] Furthermore, the plurality of water inlet channels are evenly distributed in an annular direction in the head section of the underwater vehicle.

[0012] Furthermore, the movable cover plate is rotatably connected to the rear end portion of the water inlet channel so as to be able to form two states of closing and opening.

[0013] Furthermore, the cross-sectional dimension of the movable cover plate is slightly larger than the cross-sectional dimension of the water inlet channel.

[0014] Furthermore, the double-layer elastic membrane is arranged along the entire circumference of the middle section of the underwater vehicle.

[0015] Furthermore, the grid channel and the grid support body are both fixed to the upper membrane surface of the double-layer elastic membrane.

[0016] Furthermore, when the elastic stretcher is in the open state, the maximum opening degree is 1-20°; when the elastic stretcher is in the closed state, it returns to a part of the upper membrane surface of the double-layer elastic membrane.

[0017] Furthermore, the elastic struts are arranged in arrays along the length direction and circumferential direction of the underwater vehicle.

[0018] Furthermore, the elastic spacer has a shape of triangle, semicircle, crescent, etc.

[0019] Furthermore, the ridge-like protrusions have a width of 1-3 microns, a height of 10-30 microns, and a spacing of 60-90 microns.

[0020] The beneficial effects of the present invention are:

[0021] (i) The present invention can reduce drag without additional energy input and without damaging the surface strength of the underwater vehicle, and the drag reduction capability and economic benefits are higher than existing technologies (such as hydrophobic surface, micro-groove surface, full-field fluid modification, etc.).

[0022] (ii) The present invention prepares a drag reduction liquid and fills it into the internal chamber of the double-layer elastic membrane with a variable volume. When drag reduction is not needed, the internal chamber of the double-layer elastic membrane has a pressure-maintaining effect for a certain period of time through the grid channel and the one-way Tesla valve; when drag reduction is needed, the double-layer elastic membrane is pressurized so that the drag reduction liquid will seep out from the elastic support. After the seepage, the drag reduction liquid and the micro-grooves work together to form a drag reduction layer near the boundary layer of the underwater vehicle, thereby achieving drag reduction. The operation is simple and easy, and can ensure the friction resistance reduction requirements under the conditions of external flow field or internal flow, and reduce energy consumption.

[0023] (III) Under different navigation speeds of the underwater vehicle, the water pressures received through the water inlet channel are different, resulting in different openings of the movable cover plate, thereby achieving a positive correlation between the pressure provided to the air storage chamber and the navigation speed. Therefore, the elastic strut can swing the angle of attack with the incoming flow speed, so that the seepage rate of the drag reducer increases with the increase of the navigation speed, thereby finally achieving adaptive adjustment of the drag reduction effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic diagram of the structure of a bionic drag reduction system for an underwater vehicle provided in an embodiment;

[0025] Figure 2 A schematic diagram of the structure of the unpowered charging mechanism of the underwater vehicle bionic drag reduction system provided in the embodiment;

[0026] Figure 3 A schematic diagram of the open and closed states of the movable cover plate in the unpowered charging mechanism provided in the embodiment;

[0027] Figure 4 A schematic diagram of the structure of a unidirectional Tesla valve in an unpowered charging mechanism provided in an embodiment;

[0028] Figure 5 A cross-sectional view of a bionic drag reducing agent injection mechanism in a bionic drag reducing system for an underwater vehicle of an embodiment;

[0029] Figure 6 A schematic plan view of the elastic support and micro grooves in the drag reducing agent bionic injection mechanism of the embodiment;

[0030] Figure 7 It is a schematic diagram of the open and closed states of the elastic support in the drag reducing agent bionic injection mechanism of the embodiment.

[0031] In the above figure: 1: water inlet opening; 2: water inlet channel; 3: movable cover plate; 4: air storage chamber; 5: one-way Tesla valve; 6: grid support body; 7: grid channel; 8: double-layer elastic membrane; 9: elastic support; 10: micro groove. DETAILED DESCRIPTION

[0032] In order to further understand the content, features and effects of the present invention, the following embodiments are given as examples and described in detail with reference to the accompanying drawings:

[0033] See also Figure 1 As shown, an embodiment of the present invention provides a bionic drag reduction system for an underwater vehicle based on the infiltration of a drag reducer, which mainly includes an unpowered charging mechanism and a drag reducer bionic injection mechanism.

[0034] See also Figure 2 As shown, the unpowered charging mechanism includes a water inlet opening 1, a water inlet channel 2, a movable cover plate 3, an air storage chamber 4, and a one-way Tesla valve 5.

[0035] The water inlet opening 1 is arranged on the surface of the head section of the underwater vehicle, so as to realize the communication between the outside of the underwater vehicle and the water inlet channel 1.

[0036] A plurality of water inlet channels 2 are evenly distributed in the circumferential direction in the head section of the underwater vehicle. In this embodiment, six water inlet channels 1 are provided. Each water inlet channel 1 extends in a straight line along the length direction of the underwater vehicle, and its front end is sealedly connected to the water inlet opening 1 and its rear end is sealedly connected to the air storage chamber 3.

[0037] See also Figure 3 As shown, the movable cover plate 3 is arranged at the connection between the water inlet channel 2 and the air storage chamber 4, and is rotatably connected with the rear end of the water inlet channel 2, so as to form two states of the movable cover plate 3, namely, closed and opened. The cross-sectional dimension of the movable cover plate 3 is slightly larger than the cross-sectional dimension of the water inlet channel 2, so that the movable cover plate 3 can completely cover the water inlet channel 2 in the closed state, and effectively block the communication between the water inlet channel 1 and the air storage chamber 3; and the movable cover plate 3 rotates toward the air storage chamber 4 to be in its open state.

[0038] The air storage chamber 3 is located at the connection between the head section and the middle section of the underwater vehicle. The air storage chamber 3 is pre-filled with gas with a certain pressure. The gas pressure can ensure that the movable cover plate 1 is pressed against the rear end port of the water inlet channel 1 when the underwater vehicle is in a stationary state underwater.

[0039] In this way, when the underwater vehicle is in a stationary state underwater, the movable cover plate 2 is tightly closed due to the pressure of the air storage chamber 3, thereby cutting off the communication between the water inlet channel 1 and the air storage chamber 3.

[0040] When the underwater vehicle moves forward, external water flows into the water inlet channel 2 through the water inlet opening 1 at a certain pressure, and the movable cover plate 2 opens under the influence of the water flow pressure, allowing the water flow to enter the air storage chamber 3.

[0041] See also Figure 4 As shown, the rear side of the air storage chamber 3 is connected to the inside of the double-layer elastic membrane 8 of the drag reducing agent bionic injection mechanism through the one-way Tesla valve 4. After the water flows into the air storage chamber 3, the gas inside the air storage chamber 3 enters the inside of the double-layer elastic membrane 8 through the one-way Tesla valve 4 to pressurize the double-layer elastic membrane 8. The one-way Tesla valve 4 is used to prevent the drag reducing agent in the double-layer elastic membrane 8 from flowing back to the air storage chamber 3 and to maintain the pressure of the double-layer elastic membrane 8.

[0042] See also Figure 5 As shown, the drag reducing agent bionic injection mechanism includes a grid support body 6, a grid channel 7, a double-layer elastic membrane 8, an elastic support 9, and a micro groove 10.

[0043] The double-layer elastic membrane 8 covers the outer wall surface of the middle section of the underwater navigation body, and is generally arranged along the entire circumference thereof. A closed chamber X is formed between the upper membrane surface and the lower membrane surface of the double-layer elastic membrane 8, and a drag reducing liquid is stored in the chamber X. The drag reducing liquid can affect the turbulent structure of the near-wall area, thereby reducing the wall turbulent friction resistance. In this embodiment, the drag reducing liquid is prepared by mixing hexadecyltrimethylammonium chloride (CTAC) powder, sodium salicylate (NaSal) powder and deionized water. The specific preparation process is: first dissolve the CTAC powder and NaSal powder separately in deionized water, and then mix the respective solutions; the mass ratio of CTAC powder, NaSal powder and deionized water is 1:1:500; then stir in a magnetic stirrer at a speed of 500r / min for 10-12h to mix evenly for use.

[0044] The lower membrane surface of the double-layer elastic membrane 8 is tightly fitted and installed with the outer wall surface of the underwater navigation body, for example, by bonding. The inner surface of the upper membrane surface of the double-layer elastic membrane 8 is provided with a grid channel 7, and the grid channel 7 is supported by a grid support body 6. The grid channel 7 and the grid support body 6 are both fixed to the upper membrane surface of the double-layer elastic membrane 8, which not only constitute the skeleton structure of the upper membrane surface of the double-layer elastic membrane 8, but also play a role in uniform liquid separation.

[0045] The upper membrane surface of the double-layer elastic membrane 8 covers the lower membrane surface in a natural state. After the double-layer elastic membrane 8 is pressurized, the upper membrane surface is slightly bulged, so that the volume of the chamber X between the upper membrane surface and the lower membrane surface is expanded.

[0046] See also Figure 6 As shown, the upper membrane surface of the double-layer elastic membrane 8 is provided with a plurality of seepage holes, which are evenly distributed on the permeation surface 9, and are covered by an elastic spacer 9 of the same shape. The elastic spacer 9 is made of the same material as the double-layer elastic membrane 8. The front end of the elastic spacer 9 is rotatably connected to the upper membrane surface of the double-layer elastic membrane 8, so that the elastic spacer 9 can be opened outward relative to the upper membrane surface of the double-layer elastic membrane 8. When the elastic spacer 9 is in the open state, the maximum opening is within the range of 1-20°; when the elastic spacer 9 is in the closed state, the elastic spacer 9 returns to a part of the upper membrane surface of the double-layer elastic membrane 8.

[0047] As a preferred embodiment, the elastic spacers 9 are arranged in arrays along the length direction and the circumferential direction of the underwater vehicle.

[0048] As a preferred embodiment, the elastic spacer 9 is in the shape of an isosceles triangle, the base of the isosceles triangle is rotatably connected to the upper membrane surface of the double-layer elastic membrane 8 at the front end, and the vertex angle at the rear end is preferably 10-15°. In addition to the triangle, the shape of the elastic spacer 9 can also be semicircular, crescent, etc.

[0049] The surface of the elastic spacer 9 is provided with a plurality of ridge-like protrusions with a width of 1-3 microns, each of which extends along the length direction of the underwater vehicle to form microgrooves 12 on the surface of the elastic spacer 9, and the microgrooves 12 and the elastic spacer 9 together form a shark shield scale structure. As a preferred embodiment, the height of the ridge-like protrusions is 10-30 microns, and the distance between the ridge-like protrusions is 60-90 microns.

[0050] See also Figure 7 As shown, the double-layer elastic membrane 8 is a pressure-maintaining structure in a natural state, and the elastic spacer 9 is also in a closed state; only when the double-layer elastic membrane 8 is pressurized, the drag-reducing liquid will break through the elastic spacer 9 and overflow to the outside.

[0051] Based on the above structural setting of the present invention, when the underwater vehicle is in a stationary state underwater, the gas inside the air storage chamber 3 will not enter the double-layer elastic membrane 8 through the one-way Tesla valve 4, so the elastic support 11 is in a closed state. When the underwater vehicle is moving, the movable cover plate 2 opens under the impact of the water flow, and the unpowered charging mechanism is started to pressurize the double-layer elastic membrane 8. The pressure in the chamber X space increases, so that the drag reduction liquid seeps out from the elastic support 9, thereby achieving drag reduction under the influence of the interaction between the micro groove 10 and the incoming flow of the drag reduction liquid. Under different navigation speeds, the water pressure inside the water inlet channel 2 of the underwater vehicle is different, and the opening of the movable cover plate 2 is different. The pressure provided to the air storage chamber 3 is positively correlated with the navigation speed. The elastic support 11 can swing the angle of attack with the incoming flow speed, and the seepage speed of the drag reduction liquid increases with the increase of the navigation speed, and finally realizes the adaptive adjustment of the drag reduction effect.

[0052] Although the preferred embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments, which are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms of specific changes without departing from the scope of protection of the invention and the claims, all of which fall within the scope of protection of the present invention.

Claims

1. A bionic drag reduction system for underwater vehicles based on the infiltration of drag reducers, characterized in that: It includes an unpowered charging mechanism and a drag reducing agent bionic injection mechanism; The unpowered charging mechanism includes a plurality of water inlet channels arranged in the head section of the underwater vehicle, each of which extends in a straight line along the length direction of the underwater vehicle, with its front end sealedly connected to the water inlet opening and its rear end sealedly connected to the air storage chamber; a plurality of water inlet openings are arranged on the surface of the head section of the underwater vehicle, for realizing the connection between the outside of the underwater vehicle and the water inlet channel; a movable cover is arranged at the connection between each of the water inlet channels and the air storage chamber, and the movable cover can completely cover the water inlet channel in a closed state and can rotate toward the air storage chamber in an open state; the air storage chamber is located at the connection between the head section and the middle section of the underwater vehicle, and the interior of the air storage chamber is pre-filled with gas of a certain pressure; the air storage chamber is connected to the interior of the double-layer elastic membrane of the drag reducer bionic injection mechanism through a one-way conduction Tesla valve; The drag reducing agent bionic injection mechanism comprises a double-layer elastic membrane covering the outer wall surface of the middle section of the underwater vehicle, a closed chamber is formed between the upper membrane surface and the lower membrane surface of the double-layer elastic membrane, and the drag reducing liquid is stored in the chamber; the lower membrane surface of the double-layer elastic membrane is tightly fitted and installed with the outer wall surface of the underwater vehicle, and a grid channel is arranged on the inner surface of the upper membrane surface of the double-layer elastic membrane, and the grid channel is supported by a grid support body; the upper membrane surface of the double-layer elastic membrane covers the lower membrane surface in a natural state, and the upper membrane surface of the double-layer elastic membrane bulges after the double-layer elastic membrane is pressurized to expand the volume of the chamber; the upper membrane surface of the double-layer elastic membrane is provided with a plurality of seepage holes, and the seepage holes are evenly distributed on the permeation surface and covered by elastic struts with the same shape as the seepage holes; The elastic support is made of the same material as the double-layer elastic membrane; The front end of the elastic support is rotatably connected to the upper membrane surface of the double-layer elastic membrane, so that the elastic support can be opened outwards; The elastic spacer surface is provided with a plurality of ridge-like protrusions, each of which extends along the length direction of the underwater vehicle to form micro grooves on the elastic spacer surface; When the underwater vehicle is in a stationary state underwater, the movable cover plate is pressed against the rear end of the water inlet channel under the action of the gas inside the air storage chamber. At this time, the gas inside the air storage chamber will not enter the double-layer elastic membrane, and thus the elastic support block is in a closed state; when the underwater vehicle is in a forward state, water flows into the water inlet channel through the water inlet opening, and the movable cover plate is opened due to the influence of the water flow pressure, thereby allowing the water flow to enter the air storage chamber, and then the gas inside the air storage chamber enters the double-layer elastic membrane through the unidirectional Tesla valve to pressurize the double-layer elastic membrane. At this time, the drag reducing liquid inside the double-layer elastic membrane overflows to the outside through the elastic support block.

2. The bionic drag reduction system for underwater vehicles based on the infiltration of drag reducers according to claim 1 is characterized in that: The plurality of water inlet channels are evenly distributed in an annular direction in the head section of the underwater vehicle.

3. The underwater vehicle bionic drag reduction system based on the infiltration of drag reducer according to claim 1 is characterized in that: The movable cover plate is rotatably connected to the rear end of the water inlet channel so as to be able to form two states of closing and opening.

4. The bionic drag reduction system for underwater vehicles based on the infiltration of drag reducers according to claim 1, characterized in that: The cross-sectional dimension of the movable cover plate is slightly larger than the cross-sectional dimension of the water inlet channel.

5. The underwater vehicle bionic drag reduction system based on the infiltration of drag reducer according to claim 1 is characterized in that: The double-layer elastic membrane is arranged along the entire circumference of the middle section of the underwater vehicle.

6. The bionic drag reduction system for underwater vehicles based on the infiltration of drag reducers according to claim 1, characterized in that: The grid channel and the grid support body are both fixed to the upper membrane surface of the double-layer elastic membrane.

7. The bionic drag reduction system for underwater vehicles based on the infiltration of drag reducers according to claim 1, characterized in that: When the elastic stretcher is in the open state, the maximum opening degree is 1-20°; when the elastic stretcher is in the closed state, it returns to a part of the upper membrane surface of the double-layer elastic membrane.

8. The bionic drag reduction system for underwater vehicles based on the infiltration of drag reducers according to claim 1, characterized in that: The elastic stays are arranged in arrays along the length direction and the circumferential direction of the underwater vehicle.

9. The bionic drag reduction system for underwater vehicles based on the infiltration of drag reducers according to claim 1, characterized in that: The elastic spacer has a shape of a triangle, a semicircle, or a crescent.

10. The bionic drag reduction system for underwater vehicles based on the infiltration of drag reducers according to claim 1, characterized in that: The ridge-shaped protrusions have a width of 1-3 microns, a height of 10-30 microns, and a spacing of 60-90 microns.

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