A ship navigation drag reduction device

Abstract

The application relates to the technical field of ship design and manufacturing, in particular to a ship sailing resistance reduction device. In the process of ship sailing, pumped gas and water are first guided to a primary mixing cavity, undergo primary mixing to generate a primary bubble mixture, are then sprayed towards a flow dividing disc, are divided into a left secondary mixing sub-cavity and a right secondary mixing sub-cavity after collision, undergo mixing to generate a left secondary bubble mixture and a right secondary bubble mixture, and are then guided to a tertiary mixing cavity to generate a tertiary bubble mixture. Due to multiple mixing, the bubbles in the tertiary bubble mixture are more delicate in shape and more dense in distribution. In the mixing process of high-pressure gas and high-pressure water, the generation process of the bubbles is mainly affected by the turbulent flow effect instead of simply relying on the modification of the ship body design structure, thereby eliminating the dependence on water quality conditions and sailing speed.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of ship design and manufacturing technology, and particularly relates to a ship sailing drag reduction device. BACKGROUND

[0002] As early as in the 1830s, Russian and Swedish scientists proposed a design concept of using bubbles to reduce the sailing drag of a ship. In brief, a bubble generating device is arranged at a bottom plate of the ship, and then bubbles are introduced between the outer surface of the ship body and water to form a bubble layer for reducing the frictional drag of the ship.

[0003] The design concept of bubble drag reduction is not easy to implement in engineering practice. For example, a Chinese invention patent discloses a bubble drag reduction device for the bow of a ship, which includes two sets of bubble generating plate assemblies. The two sets of bubble generating plate assemblies are symmetrically arranged on both sides of the bow of the ship relative to the hull and are inclined downward relative to the horizontal plane. The bubble generating plate assemblies are arranged along the streamline of the hull. The bubble generating plate assembly includes a first bubble generating plate, a second bubble generating plate, a third bubble generating plate, and a fourth bubble generating plate arranged at intervals along the streamline of the hull. The distance between the first bubble generating plate and the horizontal plane, the distance between the second bubble generating plate and the horizontal plane, the distance between the third bubble generating plate and the horizontal plane, and the distance between the fourth bubble generating plate and the horizontal plane gradually increase. The angles between the first bubble generating plate and the horizontal plane, the angles between the second bubble generating plate and the horizontal plane, the angles between the third bubble generating plate and the horizontal plane, and the angles between the fourth bubble generating plate and the horizontal plane gradually increase. In actual navigation, bubble generating plate assemblies are arranged at intervals along the streamline of the hull. These assemblies utilize the theory of cavitation generation—that when there is a large negative pressure, air is drawn into the water to generate bubbles. The bubble generating plate assemblies, arranged at intervals along the streamline of the hull, hold these bubbles against the hull and allow them to flow with the water current, exiting from the stern. This layer of air acts as a lubricant, thus achieving the design goal of reducing the ship's drag. For example, Chinese invention patent CN110758633A discloses a Venturi system for hull drag reduction using bubble generation, which includes a hull structure and a Venturi tube array. The Venturi tube array consists of several Venturi tubes, and the structure of each Venturi tube mainly includes a Venturi inlet section, a Venturi converging section, a Venturi throat section, a Venturi expanding section, and a Venturi extension section. By incorporating a Venturi structure into the ship's interior and utilizing the bubble ejection mechanism of the Venturi tube, air is drawn into the Venturi tube to form a bubble cluster as the ship moves forward. This bubble cluster is then delivered to the bottom of the hull, coating the bottom surface and altering the flow pattern of the fluid at the hull bottom. While both of these technical solutions can effectively form a bubble drag-reducing layer at the waterline of the hull,… However, the following shortcomings also exist, which will inevitably affect the drag reduction effect during ship navigation: 1) No energy is actively input during the bubble generation process; it relies solely on the modification design of the hull structure. Due to the influence of water quality conditions and navigation speed, the generated bubbles may not be able to form a drag-reducing bubble layer that meets the expected requirements under some extreme conditions; 2) Because the bubbles are generated in a natural state, the formation process cannot be precisely controlled, resulting in insufficient bubble fineness, meaning that the size and distribution density of the formed bubbles are difficult to meet design requirements; 3) The bubble generating device (such as the bubble generating plate assembly and Venturi structure mentioned above) is frequently blocked by debris, causing the bubble generation process to be interrupted, requiring frequent and substantial investment of manpower and resources for maintenance. Therefore, this provides a new research direction for our research group. SUMMARY

[0004] Therefore, in view of the above-mentioned problems and defects, the present application is developed based on the collection of relevant information, the evaluation and consideration of various parties, and the continuous experiments and modifications of the research team, and finally leads to the emergence of the ship navigation drag reduction device.

[0005] To solve the above-mentioned technical problems, the present application relates to a ship navigation drag reduction device for forming a drag reduction bubble layer near the bottom plate area of a ship. The ship navigation drag reduction device comprises an air inlet channel, a liquid inlet channel, a first mixing chamber, a second mixing chamber, a third mixing chamber, a flow divider, and an outlet channel. The second mixing chamber is composed of a left second mixing sub-chamber and a right second mixing sub-chamber. The flow divider is arranged in the second mixing chamber, located directly below the first mixing chamber, and simultaneously across the left second mixing sub-chamber and the right second mixing sub-chamber. The gas pumped through the air inlet channel and the water pumped through the liquid inlet channel are preliminarily mixed in the first mixing chamber to form a primary bubble mixture. The primary bubble mixture is collided by the flow divider and is divided into the left second mixing sub-chamber and the right second mixing sub-chamber, and is mixed again to form a left second bubble mixture and a right second bubble mixture. The left second bubble mixture and the right second bubble mixture are jointly introduced into the third mixing chamber, mixed to form a third bubble mixture which is discharged through the outlet channel and directly reaches the bottom plate area of the ship.

[0006] As a further improvement of the disclosed technical solution of the present application, a primary mixing unit is arranged in the first mixing chamber. The primary mixing unit comprises a gas distribution pipe and a spoiler. The gas distribution pipe and the spoiler are both arranged in the first mixing chamber and are sequentially arranged along the up-down direction. The gas distribution pipe is directly connected with the air inlet channel. The spoiler continuously performs a circumferential rotation motion due to the impact force of the water pumped through the liquid inlet channel.

[0007] As a further improvement of the disclosed technical solution, a secondary mixing unit is arranged in the secondary mixing chamber. The secondary mixing unit is composed of a left-arranged secondary mixing subunit arranged in the left-arranged secondary mixing subchamber and a right-arranged secondary mixing subunit arranged in the right-arranged secondary mixing subchamber. The left-arranged secondary mixing subunit comprises a left-arranged bubble generating part and a left-arranged volume compression device. The left-arranged bubble generating part is composed of a plurality of left-arranged bubble generating plates arranged in the left-arranged secondary mixing subchamber in a transverse direction and sequentially arranged in a vertical direction. The left-arranged volume compression device is arranged directly below the left-arranged bubble generating part and is applied in conjunction with the left-arranged bubble generating part. The right-arranged secondary mixing subunit comprises a right-arranged bubble generating part and a right-arranged volume compression device. The right-arranged bubble generating part is composed of a plurality of right-arranged bubble generating plates arranged in the right-arranged secondary mixing subchamber in a transverse direction and sequentially arranged in a vertical direction. The right-arranged volume compression device is arranged directly below the right-arranged bubble generating part and is applied in conjunction with the right-arranged bubble generating part. The left-arranged bubble generating plates are uniformly provided with a plurality of left-arranged flow-through holes. The right-arranged bubble generating plates are uniformly provided with a plurality of right-arranged flow-through holes. In the working state, after the left-arranged bubble generating plates and the right-arranged bubble generating plates are completely immersed by the primary bubble mixture separated by the flow divider, the left-arranged volume compression device and the right-arranged volume compression device are simultaneously started, the left-arranged bubble generating plates and the right-arranged bubble generating plates are kept in a high-frequency excitation state due to the impact kinetic energy, the primary bubble mixture remaining in the left-arranged secondary mixing subchamber overflows through the left-arranged flow-through holes under the action of pressure to form a left-arranged secondary bubble mixture, and at the same time, the primary bubble mixture remaining in the right-arranged secondary mixing subchamber overflows through the right-arranged flow-through holes under the action of pressure to form a right-arranged secondary bubble mixture.

[0008] As a further improvement of the disclosed technical solution, the left-arranged volume compression device comprises a left-arranged push plate and a left-arranged excitation generating element. The left-arranged push plate is arranged in the left-arranged secondary mixing subchamber and is accompanied by a left-arranged sealed subchamber formed directly below the left-arranged push plate to accommodate the left-arranged excitation generating element. The right-arranged volume compression device comprises a right-arranged push plate and a right-arranged excitation generating element. The right-arranged push plate is arranged in the right-arranged secondary mixing subchamber and is accompanied by a right-arranged sealed subchamber formed directly below the right-arranged push plate to accommodate the right-arranged excitation generating element. In the working state, after the left-arranged bubble generating plates and the right-arranged bubble generating plates are completely immersed by the primary bubble mixture, the left-arranged excitation generating element and the right-arranged excitation generating element are simultaneously started, and the left-arranged push plate and the right-arranged push plate perform high-frequency small-distance displacement movement in the vertical direction under the action of excitation force.

[0009] As a further improvement of the disclosed technical solution, the left-arranged excitation generating element and the right-arranged excitation generating element can be preferably vibration motors.

[0010] As a further improvement of the disclosed technical solution, the tertiary mixing cavity is provided with a tertiary mixing unit.

[0011] As a further improvement of the disclosed technical solution, the number of the liquid inlet channels is 1.

[0012] As a further improvement of the disclosed technical solution, in a unit time, assuming that the amount of liquid pumped in through the liquid inlet channel is A, and the amount of gas pumped in through the gas inlet channel is B, then A / B≥5.

[0013] As a further improvement of the disclosed technical solution, the ship navigation drag reduction device further comprises a foam booster.

[0014] As a further improvement of the disclosed technical solution, the foam booster is preferably a polyurethane foam body or a water-permeable sponge body.

[0015] In the process of ship navigation, the pumped gas and water are first jointly guided into the primary mixing cavity, undergo primary mixing to generate a primary bubble mixture, and then the primary bubble mixture is injected towards the flow distribution disc and after collision is distributed to the left secondary mixing sub-cavity and the right secondary mixing sub-cavity, undergoes secondary mixing to generate a left secondary bubble mixture and a right secondary bubble mixture, and then is guided into the tertiary mixing cavity, undergoes tertiary mixing to generate a tertiary bubble mixture, and finally, it is discharged through the discharge channel and directly to the ship bottom area.

[0016] In actual implementation and application, the ship navigation drag reduction device can at least achieve the following beneficial technical effects, specifically:

[0017] 1) In the mixing process of high-pressure gas and high-pressure water, due to the influence of turbulent flow effect, a large number of bubbles are generated, not simply relying on the modification of the ship body design structure to achieve, thereby eliminating the dependence of the bubble formation process on water quality conditions and navigation speed, and facilitating the formation of a drag-reducing bubble layer meeting the expected requirements at the bottom of the ship;

[0018] 2) can be fine control of the formation process of the bubble, specifically manifested as: high pressure gas and high pressure water body in turn are introduced into the first mixing chamber, secondary mixing chamber, three mixing chamber, through mixing, so as to facilitate the formation of more delicate bubble (three liquid bubble mixture contains bubble size is small, and the distribution of better density). In this way, the water area near the ship bottom plate is injected into micro bubble, in the process of rapid navigation of the ship, the micro bubble and the turbulent flow can form good interaction, the turbulent model of the boundary layer of the ship is optimized, the turbulent fluctuation is greatly inhibited, finally, it is conducive to the reduction of the ship sailing resistance;

[0019] 3) under the action of super high injection pressure, the discharge channel is difficult to be blocked by sundries, so that not only the generation process of the bubble can be maintained in the normal state during the ship sailing, ensuring that the ship always maintains the low resistance sailing state, which is conducive to reducing the sailing energy consumption, but also the frequency and cost of the later maintenance of the ship can be greatly reduced. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0021] Figure 1 is the structure diagram of the first embodiment of the ship sailing resistance reduction device in the present application.

[0022] Figure 2 is the I partial enlarged view of Figure 1 .

[0023] Figure 3 is the II partial enlarged view of Figure 1 .

[0024] Figure 4 is the III partial enlarged view of Figure 1 .

[0025] Figure 5 is the structure diagram of the second embodiment of the ship sailing resistance reduction device in the present application.

[0026] Figure 6 is the structure diagram of the third embodiment of the ship sailing resistance reduction device in the present application.

[0027] 1 - air inlet channel; 2 - liquid inlet channel; 3 - primary mixing chamber; 31 - primary mixing unit; 311 - air distribution pipe; 312 - spoiler plate; 4 - secondary mixing chamber; 41 - left secondary mixing sub-chamber; 411 - left sealing sub-chamber; 42 - right secondary mixing sub-chamber; 421 - right sealing sub-chamber; 43 - secondary mixing unit; 431 - left secondary mixing sub-unit; 4311 - left bubble generating part; 43111 - left bubble generating plate; 4312 - left volume compression device; 43121 - left push plate; 43122 - left vibration motor; 43123 - left stretchable rubber connecting body; 432 - right secondary mixing sub-unit; 4321 - right bubble generating part; 43211 - right bubble generating plate; 4322 - right volume compression device; 43221 - right push plate; 43222 - right vibration motor; 43223 - right stretchable rubber connecting body; 5 - tertiary mixing chamber; 51 - tertiary mixing unit; 511 - arc-shaped collision plate; 6 - flow distribution disc; 7 - discharge channel; 8 - water-permeable sponge body. DETAILED DESCRIPTION

[0028] In the description of the present application, it should be understood that the terms "front", "back", "up", "down", "left", "right" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0029] In actual application, a single ship needs to be equipped with multiple sets of ship navigation drag reduction devices at the same time to form a drag reduction bubble layer near the bottom plate area directly below it to reduce the navigation resistance and save energy consumption.

[0030] The disclosed content will be further described in detail below in combination with specific embodiments, Figure 1 , Figure 2 , Figure 3 , Figure 4The first embodiment of the ship sailing resistance reduction device is shown in the structure diagram. It is mainly composed of an air inlet channel 1, a liquid inlet channel 2, a first mixing chamber 3, a second mixing chamber 4, a third mixing chamber 5, a flow dividing disc 6 and an outlet channel 7. The air inlet channel 1 and the liquid inlet channel 2 are directly connected with the first mixing chamber 3. The number of the liquid inlet channel 1 is 1. The number of the air inlet channel is 2, which is symmetrically distributed on the left and right sides of the liquid inlet channel 3. The second mixing chamber is located directly below the first mixing chamber 3, which is composed of a left second mixing sub-chamber 41 and a right second mixing sub-chamber 42. The flow dividing disc 6 is built-in and fixed in the second mixing chamber 4, and it spans the left second mixing sub-chamber 41 and the right second mixing sub-chamber 42. The gas pumped through the air inlet channel 1 and the water pumped through the liquid inlet channel 2 are preliminarily mixed in the first mixing chamber 3 to form a primary bubble mixture. In the subsequent flow process, the primary bubble mixture is collided by the flow dividing disc 6 and is divided into the left second mixing sub-chamber 41 and the right second mixing sub-chamber 42, and is mixed again to form a left second bubble mixture and a right second bubble mixture. The left second bubble mixture and the right second bubble mixture are introduced into the third mixing chamber 5, mixed to form a third bubble mixture which is discharged through the outlet channel 7 and directly reaches the ship bottom area.

[0031] In actual implementation and application, the ship sailing resistance reduction device can achieve the following beneficial technical effects:

[0032] 1) In the mixing process of high-pressure gas and high-pressure water, due to the influence of turbulent flow effect, a large number of bubbles are generated, not simply relying on the modification of the ship body design structure, thereby eliminating the dependence of the bubble formation process on water quality conditions and sailing speed, and facilitating the formation of a bubble layer that meets the expected requirements at the bottom of the ship;

[0033] 2) The formation process of the bubbles can be precisely controlled, which is specifically manifested as: high-pressure gas and high-pressure water are sequentially introduced into the first mixing chamber 3, the second mixing chamber 4 and the third mixing chamber 5, and undergo multiple mixing, thereby facilitating the formation of more delicate bubbles (the size of the bubbles contained in the third bubble mixture is extremely small, and the distribution is better). In this way, the water near the ship bottom is injected with micro-bubbles, which can form good interaction between the micro-bubbles and the turbulent flow in the process of rapid sailing of the ship, the turbulent model of the boundary layer is optimized, and the turbulent pulsation is greatly suppressed, which is finally beneficial to the reduction of the sailing resistance of the ship;

[0034] 3) The discharge passage 7 is hardly blocked by foreign matters under the action of the super-high injection pressure, thus not only ensuring that the generation process of the bubbles is maintained in a normal state during the navigation of the ship, ensuring that the ship always maintains a low-resistance navigation state, which is beneficial to reduce the navigation energy consumption, but also greatly reducing the frequency and cost of the later maintenance of the ship.

[0035] It is known that, according to design common sense, the primary mixing chamber 3 can adopt various design structures to realize the mixing of high-pressure gas and high-pressure water to generate a primary bubble mixture. However, a design structure that is simple to manufacture and has a very rich bubble content in the generated primary bubble mixture is recommended, as follows: as shown in Figure 1 , a primary mixing unit 31 is arranged in the primary mixing chamber 3. As shown in Figure 2 , the primary mixing unit 31 includes a gas distribution pipe 311 and a spoiler 312. The gas distribution pipe 311 and the spoiler 312 are both arranged in the primary mixing chamber 3 and are arranged in sequence along the up-down direction. The gas distribution pipe 311 is directly connected to the gas inlet passage 1. The main structure of the gas distribution pipe 311 is a circular pipe, and a plurality of air holes (the diameter of the air holes is controlled to be 0.2-0.5mm) are uniformly distributed around the circumferential side wall. The spoiler 312 continuously performs a circumferential rotation motion due to the impact force of the water pumped in through the liquid inlet passage 2.

[0036] For the same design purpose, similarly, as shown in Figure 1 , a secondary mixing unit 43 can be arranged in the secondary mixing chamber 4. The secondary mixing unit 43 is composed of a left secondary mixing sub-unit 431 arranged in the left secondary mixing sub-chamber 41 and a right secondary mixing sub-unit 432 arranged in the right secondary mixing sub-chamber 42. As shown in Figure 3 , the left secondary mixing sub-unit 431 includes a left bubble generation part 4311 and a left volume compression device 4312. The left bubble generation part 4311 is composed of a plurality of left bubble generation plates 43111 arranged in the left secondary mixing sub-chamber 41 and arranged in sequence along the up-down direction. The left volume compression device 4312 is arranged directly below the left bubble generation part 4311 and is applied in conjunction with the left bubble generation part 4311. The left bubble generation plate 43211 is uniformly provided with a plurality of left flow-through holes. As shown in Figure 4As shown in the figure, the right-located secondary mixing subunit 432 comprises a right-located bubble generating part 4321 and a right-located volume compression device 4322. The right-located bubble generating part 4321 is composed of a plurality of right-located bubble generating plates 43211 which are horizontally arranged in the right-located secondary mixing subcavity 42 and sequentially arranged along the up-down direction. The right-located volume compression device 4322 is arranged right below the right-located bubble generating part 4321 and is used in conjunction with the right-located bubble generating part 4321. The right-located bubble generating plates 43211 are uniformly provided with a plurality of right-located flow-through holes. In actual application, the primary bubble mixture which is divided by the flow dividing disc 6 flows into the left-located secondary mixing subcavity 41 and the right-located secondary mixing subcavity 42 in the initial state until the left-located bubble generating plates 43111 and the right-located bubble generating plates 43211 are gradually submerged. In the formal working state, the left-located volume compression device 4312 and the right-located volume compression device 4322 are started, and the left-located bubble generating plates 43211 and the right-located bubble generating plates 43211 are kept in the high-frequency vibration state due to the impact kinetic energy, thereby causing the primary bubble mixture remaining in the left-located secondary mixing subcavity 41 to overflow through the left-located flow-through holes under the action of pressure to form the left-located secondary bubble mixture, and at the same time, the primary bubble mixture remaining in the right-located secondary mixing subcavity 42 overflows through the right-located flow-through holes under the action of pressure to form the right-located secondary bubble mixture. Whether the primary bubble mixture overflows through the left-located flow-through holes or the right-located flow-through holes, the gas can be more fully mixed into the water, and due to the high-frequency vibration energy, the gas bubbles tend to be smaller in size. It should be noted that in the process of formally generating the bubbles, the left-located bubble generating plates 43111 and the right-located bubble generating plates 43211 are both in the submerged state of the primary bubble mixture.

[0037] It should be noted that through long-term experimental demonstration, when the diameters of the left-located flow-through holes and the right-located flow-through holes are controlled at 0.1-0.15 mm, the left-located secondary bubble mixture and the right-located secondary bubble mixture which are generated subsequently contain more abundant, delicate and relatively small in radial size and more dense gas bubbles.

[0038] As a further refinement of the above technical solution, as shown in the figure, Figure 3 As shown in the figure, the left-located volume compression device 4312 is mainly composed of a left-located push-up plate 43121 and a left-located vibration motor 43122. The left-located push-up plate 43121 is horizontally arranged in the left-located secondary mixing subcavity 41, and a left-located sealed subcavity 411 for accommodating the left-located vibration motor 43122 is formed right below the left-located push-up plate 43121. As shown in the figure, Figure 4As shown, the right-side volumetric compression device 4322 mainly consists of a right-side push plate 43221 and a right-side vibrating motor 43222. The right-side push plate 43221 is horizontally placed in the right-side secondary mixing sub-cavity 42, and incidentally, a right-side sealed sub-cavity 421 is formed directly below it to accommodate the right-side vibrating motor 43222. In the initial stage, the primary bubble mixture flows through the left-side and right-side through holes to the left-side secondary mixing sub-cavity 41 and the right-side secondary mixing sub-cavity 42, respectively, until the left-side bubble generating plate 43111 and the right-side bubble generating plate 43211 are completely submerged by the primary bubble mixture. In operation, the left-side vibration motor 43122 and the right-side vibration motor 43222 start simultaneously. Under the action of the excitation force, the left-side push plate 43121 and the right-side push plate 43221 perform high-frequency, short-distance reciprocating motion in the vertical direction. Thus, the primary bubble mixture remaining directly above the left-side push plate 43121 and the right-side push plate 43221 overflows through the left-side and right-side through-holes respectively under the action of reciprocating extrusion force. This process is repeated, continuously generating secondary bubble mixtures on the left and right sides, rich in fine bubbles. Furthermore, multiple experiments have demonstrated that when the vibration frequency of both the left-side and right-side vibration motors 43122 and 43222 is controlled at 120–180 r / min, and the amplitude is controlled at 6–12 mm, the resulting tertiary bubble mixture contains finer and denser bubbles.

[0039] As Figure 1 , 3 As shown in Figure 4, a three-stage mixing unit 51 is provided in the three-stage mixing chamber 5. The three-stage mixing unit 51 is composed of multiple arc-shaped collision plates 511 fixed to the side wall of the three-stage mixing chamber 5 and staggered in sequence along the vertical direction. Thus, on the one hand, in actual operation, when the left-side and right-side secondary bubble mixtures flow through the tertiary mixing chamber 5, the bubbles contained within them are subjected to multi-layered collision forces from multiple arc-shaped collision plates 511, causing them to split and refine a second time. This ensures that the final tertiary bubble mixture contains a richer number of bubbles and has a more delicate overall shape (specifically, smaller bubble sizes). On the other hand, after the tertiary bubble mixture is generated, before it is discharged through the discharge channel 7, a large amount of the tertiary bubble mixture will inevitably remain in the tertiary mixing chamber 5, and some of it will flow at high speed in the gaps formed by multiple arc-shaped collision plates 511, which is conducive to the occurrence of turbulence. This not only provides a good foundation for the full fusion of gas and water, but also makes the bubbles in the tertiary bubble mixture more delicate and dense.

[0040] In the process of ship sailing, the pumped gas and water are first guided into the primary mixing chamber 3, and under the joint action of the gas distribution pipe 311 and the spoiler 312, they undergo a preliminary mixing to generate a primary bubble mixture. In this case, the size of the gas bubbles is large, and the number is small. Then the primary bubble mixture is injected towards the flow divider 6, and after collision, it is divided into the left secondary mixing sub-chamber 41 and the right secondary mixing sub-chamber 42. Under the joint action of the left secondary mixing sub-unit 431 and the right secondary mixing sub-unit 432, the primary bubble mixture undergoes secondary mixing to generate a left secondary bubble mixture and a right secondary bubble mixture. In this case, the size of the gas bubbles is small, and the number is greatly increased. Then it is guided into the tertiary mixing chamber 5, and under the joint action of the plurality of arc-shaped collision plates 511, it undergoes tertiary mixing to generate a tertiary bubble mixture. Finally, it is discharged through the discharge passage 7 and directly reaches the ship bottom area.

[0041] It should be noted that the richness and fineness of the bubbles in the finally generated tertiary bubble mixture are affected by the water-gas mixing ratio in addition to the gas inlet pressure, the water inlet pressure and the mixing method. Therefore, assuming that the amount of liquid pumped through the liquid inlet passage 2 is A and the amount of gas pumped through the gas inlet passage 1 is B in a unit of time, when A / B≥5, the shape of the finally generated tertiary bubble mixture is optimal, which is beneficial to the formation of a high-quality drag reduction bubble layer in the vicinity of the ship bottom area.

[0042] Figure 5 The structure schematic diagram of the second embodiment of the ship sailing drag reduction device is shown. Compared with the first embodiment, the difference lies in that a water-permeable sponge body 8 is also attached to the flow divider 6, and preferably covers the top wall. In this way, without affecting the basic flow dividing function of the flow divider 6, when the high-pressure water and high-pressure gas are mixed in the primary mixing chamber 3, they first meet the water-permeable sponge body 8 in the process of continuing to spray downward. Since the water-permeable sponge body 8 itself contains a large number of interconnected cavities, it is beneficial to the splitting and refinement of the bubbles when they flow between the cavities. Moreover, the water-permeable sponge body 8 itself has excellent hydrophilicity, which is beneficial to reducing the interfacial potential energy during gas-liquid mixing, thereby providing a good foundation for the gas to be more fully mixed into the water.

[0043] Of course, in addition to the above-mentioned water-permeable sponge body 8 for splitting and refining the bubbles, other materials rich in cavities such as polyurethane bubble bodies can also be selected according to different actual application scenarios.

[0044] When the first embodiment is applied, in actual operation, the left push-up plate 43121 needs to frequently perform high-frequency small-distance displacement motion along the inner side wall of the left secondary mixed sub-cavity 41 under the action of the exciting force, and the right push-up plate 43221 needs to frequently perform high-frequency small-distance displacement motion along the inner side wall of the right secondary mixed sub-cavity 42 under the action of the exciting force. For the sake of sealing, the left push-up plate 43121 and the right push-up plate 43221 need to be matched with a sealing part with extremely complex structure, which not only significantly increases the manufacturing cost, but also keeps the energy consumption of the left vibration motor 43122 and the right vibration motor 43222 high. More importantly, with the extension of time, the sealing elements used in the sealing part are prone to aging, which leads to sealing failure, and further leads to the invasion of water into the left vibration motor 43122 in the left sealed sub-cavity 411 and the right vibration motor 43222 in the right sealed sub-cavity 421, which not only reduces the working performance, but also greatly increases the protection difficulty, which is not conducive to the normal maintenance of the service life. In view of this, Figure 6 The structural schematic diagram of the third embodiment of the ship sailing resistance reduction device in the application is shown, and it can be known that the difference between the third embodiment and the first embodiment is that the left volume compression device 4312 is additionally provided with a left stretchable rubber connecting body 43123 on the basis of the original left push-up plate 43121 and the left vibration motor 43122. The two ends of the left stretchable rubber connecting body 43123 are connected to the inner side wall of the left secondary mixed sub-cavity 41 and the outer edge of the left push-up plate 43121 respectively. The right volume compression device 4322 is additionally provided with a right stretchable rubber connecting body 43223 on the basis of the original right push-up plate 43221 and the right vibration motor 43222. The two ends of the right stretchable rubber connecting body 43223 are connected to the inner side wall of the right secondary mixed sub-cavity 42 and the outer edge of the right push-up plate 43221 respectively. In actual operation, when the left vibration motor 43122 and the right vibration motor 43222 are started, the left push-up plate 43121 and the right push-up plate 43221 reciprocally perform small-distance displacement motion in the up-down direction due to the action of the exciting force, and the left stretchable rubber connecting body 43123 and the right stretchable rubber connecting body 43223 adaptively stretch and contract, and the volume of the left secondary mixed sub-cavity 41 (the part above the left push-up plate 43121) and the right secondary mixed sub-cavity 42 (the part above the right push-up plate 43221) changes, which makes a good preparation for the subsequent overflow of the primary bubble mixture through the left and right flow-through holes.

[0045] The foregoing description of the disclosed embodiments enables a person skilled in the art to make or use the application. Modifications of these embodiments will occur to persons of skill in the art, and that the appended claims are intended to cover all such modifications that do not depart from the true spirit and scope of the application. Therefore, the application is not limited to the embodiments shown but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A drag-reducing device for ships, used to form a drag-reducing bubble layer directly below the ship and near its bottom plate, characterized in that, It includes an air inlet channel, a liquid inlet channel, a primary mixing chamber, a secondary mixing chamber, a tertiary mixing chamber, a flow divider, and an outlet channel; the secondary mixing chamber is composed of a left secondary mixing sub-chamber and a right secondary mixing sub-chamber; the flow divider is built into the secondary mixing chamber, located directly below the primary mixing chamber, and spans both the left and right secondary mixing sub-chambers; The gas pumped in through the air inlet channel and the water pumped in through the liquid inlet channel are initially mixed in the primary mixing chamber to form a primary bubble mixture. The primary bubble mixture is impacted by the diverting plate and diverted to the left and right secondary mixing sub-cavities, where it is mixed again to form a left secondary bubble mixture and a right secondary bubble mixture, respectively. The left and right secondary bubble mixtures are then introduced into the tertiary mixing cavity and mixed to form a tertiary bubble mixture that is discharged through the discharge channel and reaches the bottom plate area of ​​the ship. A secondary mixing unit is provided in the secondary mixing chamber; the secondary mixing unit consists of a left secondary mixing sub-unit built into the left secondary mixing sub-chamber and a right secondary mixing sub-unit built into the right secondary mixing sub-chamber; the left secondary mixing sub-unit includes a left bubble generating section and a left volume compression device; the left bubble generating section consists of multiple left bubble generating plates that are transversely located in the left secondary mixing sub-chamber and arranged sequentially in the vertical direction; the left volume compression device is arranged directly below the left bubble generating section and is used in conjunction with the left bubble generating section; The right-side secondary mixing subunit includes a right-side bubble generator and a right-side volumetric compression device. The right-side bubble generator consists of multiple right-side bubble generating plates arranged sequentially in the vertical direction within the right-side secondary mixing sub-cavity. The right-side volumetric compression device is positioned directly below the right-side bubble generator and is used in conjunction with it. Multiple left-side flow holes are evenly distributed on the left-side bubble generating plate. Multiple right-side flow holes are evenly distributed on the right-side bubble generating plate. In operation, when the left-side and right-side bubble generating plates are separated by the flow divider... After the primary bubble mixture after diversion is completely submerged, the left-side volumetric compression device and the right-side volumetric compression device are activated simultaneously. The left-side bubble generating plate and the right-side bubble generating plate are kept in a high-frequency excitation state due to the impact kinetic energy. The primary bubble mixture remaining in the left-side secondary mixing sub-cavity overflows through the left-side perforation hole under pressure to form the left-side secondary bubble mixture. At the same time, the primary bubble mixture remaining in the right-side secondary mixing sub-cavity overflows through the right-side perforation hole under pressure to form the right-side secondary bubble mixture.

2. The ship navigation drag reduction device according to claim 1, characterized in that, A primary mixing unit is provided in the primary mixing chamber; the primary mixing unit includes a gas distribution pipe and a baffle plate; the gas distribution pipe and the baffle plate are both built into the primary mixing chamber and are arranged alternately in the vertical direction; the gas distribution pipe is directly connected to the air inlet channel; the baffle plate continuously performs circumferential rotation due to the impact force of the water pumped in through the liquid inlet channel.

3. The ship navigation drag reduction device according to claim 1, characterized in that, The left-side volume compression device includes a left-side push plate and a left-side excitation generating element; the left-side push plate is horizontally placed in the left-side secondary mixing sub-cavity, and incidentally forms a left-side sealed sub-cavity directly below it to accommodate the left-side excitation generating element; the right-side volume compression device includes a right-side push plate and a right-side excitation generating element. The right-side pusher plate is horizontally placed in the right-side secondary mixing sub-cavity, and incidentally forms a right-side sealed sub-cavity directly below it to accommodate the right-side excitation generating element; in the working state, when the left-side bubble generating plate and the right-side bubble generating plate are completely immersed in the primary liquid bubble mixture, the left-side excitation generating element and the right-side excitation generating element are activated simultaneously, and the left-side pusher plate and the right-side pusher plate perform high-frequency small-distance displacement movement along the vertical direction under the action of the excitation force.

4. The ship navigation drag reduction device according to claim 3, characterized in that, Both the left-side excitation generating element and the right-side excitation generating element are selected as vibration motors.

5. The ship navigation drag reduction device according to claim 1, characterized in that, The three-stage mixing chamber is provided with a three-stage mixing unit; the three-stage mixing unit is composed of multiple arc-shaped collision plates fixed to the side wall of the three-stage mixing chamber and staggered in sequence along the vertical direction.

6. The ship navigation drag reduction device according to claim 1, characterized in that, The number of liquid inlet channels is set to 1; the number of air inlet channels is set to 2, and they are symmetrically distributed on the left and right sides of the liquid inlet channels.

7. The ship navigation drag reduction device according to claim 6, characterized in that, If, per unit time, the amount of liquid pumped in through the liquid inlet channel is A, and the amount of gas pumped in through the gas inlet channel is B, then A / B ≥ 5.

8. The ship navigation drag reduction device according to any one of claims 1-7, characterized in that, It also includes a foaming component; the foaming component is attached to the distribution plate and fully covers its top surface.

9. The ship navigation drag reduction device according to claim 8, characterized in that, The foaming component is a polyurethane bubble or a water-permeable sponge.

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