Bubble generator with controllable bubble size and control method

Abstract

The application discloses a bubble generating device with controllable bubble size and a control method, wherein the bubble generating device comprises a top plate arranged at the bottom of a ship, an incoming flow curved plate, an outgoing flow curved plate and a side plate; a lower exhaust hole plate is fixed between the incoming flow curved plate and the outgoing flow curved plate, and a movable upper exhaust hole plate is arranged on the lower exhaust hole plate; the upper exhaust hole plate and the lower exhaust hole plate have the same shape of exhaust holes and the same exhaust hole spacing; when the upper exhaust hole plate moves, the exhaust holes of the upper exhaust hole plate and the exhaust holes of the lower exhaust hole plate change between complete coincidence and complete non-coincidence; and the upper exhaust hole plate is connected with a driving component for moving the upper exhaust hole plate. According to the application, the bubble size can be controlled according to the speed condition, so that the optimal drag reduction effect is realized; and when the bubble generating device does not need to be arranged at the bottom of the ship, the exhaust holes can be closed by moving the upper exhaust hole plate, the sea creatures are prevented from entering the inside, and the exhaust passage is kept unobstructed.

Description

Technical Field

[0001] This invention relates to the field of marine technology, and in particular to a bubble generating device and control method with controllable bubble size. Background Technology

[0002] Bubble drag reduction technology is a relatively new and popular energy-saving and emission-reduction technology for ships in recent years. Its working principle involves installing several bubble generators on a flat area at the bottom of the hull. When the ship sails, it generates a large number of bubbles, forming a bubble layer on the hull surface. The flow characteristics of the water-bubble mixture reduce the frictional resistance of the hull surface, thereby improving the ship's energy efficiency. The bubble generator is the core component of the bubble drag reduction system, directly affecting the quality of bubble generation and the stability of the bubble layer.

[0003] Patent CN214001953U discloses a bubble lubrication drag reduction system and a ship. It discloses that the bubble lubrication drag reduction system includes a guide vane panel and a deflector vane panel; a top plate and an air pipe are connected to a compressed air chamber; the top of the guide vane panel is connected to the front side of an exhaust orifice plate, and the top of the guide vane panel is connected to the rear side of the exhaust orifice plate; the bubble generating device includes a top plate, an exhaust side plate, and an exhaust orifice plate; the air outlet of the air compressor is connected to the air outlet along the ship's direction of travel; the deflector vane panel and the deflector vane panel are bent in opposite directions. The exhaust orifice plate in this patent cannot be deformed or adjusted, therefore it cannot produce optimal drag reduction under different operating conditions.

[0004] Patent CN 216468300 U discloses a marine air layer drag reduction system and a drag reduction vessel that uses branch pipelines to regulate gas volume. The marine air layer drag reduction system using branch pipelines includes: a gas supply device, a gas delivery device, multiple pressure-stabilizing chambers, a controller, a detection device, a control valve group, and several nozzles located on the hull bottom. The gas supply device is connected to the gas delivery device; the gas delivery device is connected to each pressure-stabilizing chamber, and the gas delivery device is used to transmit the gas output from the gas supply device to each pressure-stabilizing chamber; the pressure-stabilizing chambers are located on the hull bottom, extending along the width direction of the ship and spaced apart along the length direction of the ship, and each pressure-stabilizing chamber is connected to multiple nozzles.

[0005] In bubble drag reduction technology, bubble size significantly influences the formation and evolution of bubble swarms, thereby affecting the stability of the bubble layer at the ship's bottom and the drag reduction effect. Existing bubble generators have a fixed structure that remains unchanged during navigation and cannot be adjusted according to environmental conditions during operation. However, bubble drag reduction systems need to adapt to various ship operating conditions, encountering different loading states and speeds. Fixed-type bubble generators are unlikely to produce optimal drag reduction results under all operating conditions.

[0006] Furthermore, existing bubble drag reduction technologies often employ a single air compressor to supply air to two or more bubble generators. The air supply lines to these bubble generators may experience varying pressure drops due to differences in pipe length, shape, and even the ship's trim, leading to uneven air distribution and reduced drag reduction effectiveness. Current solutions to this problem use adjustable remote-controlled valves, which require configuring an adjustable valve for each line, resulting in high costs. Moreover, many adjustable valves are hydraulically controlled, leading to inaccurate opening over time.

[0007] Existing technology cannot prevent marine organisms from entering the bubble generator when it is not working, which can easily cause blockages.

[0008] Therefore, the disadvantages of existing bubble generating devices are: (1) The size of the bubble cannot be actively adjusted, so the drag reduction effect is difficult to guarantee to reach the optimal level under different working conditions; (2) The gas volume of different bubble generators is easily unbalanced, requiring the installation of adjustable valves, which is costly and prone to damage.

[0009] (3) The exhaust port of the bubble generator is easily blocked by marine organisms. Summary of the Invention

[0010] In order to overcome the above-mentioned defects in the prior art, the present invention provides a bubble generating device and control method with controllable bubble size.

[0011] The present invention solves the above-mentioned technical problems through the following technical solution: A bubble generating device with controllable bubble size includes a top plate, an inflow curved plate, an outflow curved plate, and side plates located at the bottom of a ship. The inflow curved plate and the outflow curved plate are respectively located in front of and behind the top plate. The side plates are located on both sides of the top plate. A lower vent plate is fixed between the inflow curved plate and the outflow curved plate, and a movable upper vent plate is provided on the lower vent plate. The upper and lower vent plates have vent holes of the same shape and the same vent hole spacing. When the upper vent plate moves, the vent holes of the upper vent plate and the vent holes of the lower vent plate vary between complete overlap and complete non-overlap. The vent holes are oblong. The width of the oblong hole is 2R, and the length is L, where 3R≤L≤10R. The vent hole spacing is not less than L along the length direction of the vent hole. The upper vent plate is connected to a driving component for moving the upper vent plate.

[0012] Furthermore, the waist-shaped hole is composed of a rectangle in the middle and two semicircles at both ends of the rectangle, with the radius of the semicircles being R and the width of the rectangle being 2R.

[0013] Furthermore, the drive component is an electric drive component.

[0014] Furthermore, the length direction of the vent is longitudinal, which is the same as the length of the ship.

[0015] Furthermore, the upper exhaust plate moves in the direction of the length of the exhaust port.

[0016] A bubble control method for controllable bubble size uses the bubble generating device described above. During ship navigation, the vent is adjusted according to the ship's speed. The relationship between the actual ventilation area S of the vent and the ship's speed Vs is as follows: When Vs < 10, S = S min ; When 10 ≤ Vs ≤ 20, S = S min + (0.1Vs-1)·(S max - S min ); When Vs > 20, S = S max ; Where Vs is in units of sections; S max S represents the maximum ventilation area of ​​the exhaust port. min The minimum ventilation area of ​​the exhaust port; and S min >0.

[0017] Furthermore, the maximum ventilation area of ​​the exhaust port is the area of ​​the exhaust port.

[0018] Furthermore, the minimum ventilation area of ​​the exhaust port is πR. 2 .

[0019] Furthermore, the ship uses N bubble generating devices as described in any one of claims 1 to 5, and is supplied with air by an air compressor, where N > 1; each bubble generating device corresponds to a branch and a flow meter; the bubble control method further includes: Step 1: Determine the maximum flow rate Q measured by the flow meter. max With minimum flow Q min Does it satisfy Q? max / Q min >1.2; If so, proceed to step 2; Step 2, determine whether 0.95Sx > S min Where Sx is the actual ventilation area of ​​the exhaust port of the bubble generator in the branch with the maximum flow rate x; Step 3: If not, adjust the upper exhaust plate so that Sx = S min If so, adjust the upper exhaust plate to reduce Sx by 5%; then repeat step 1.

[0020] Furthermore, the flow meter is connected to a controller that can receive signals from the flow meter and control the drive components, and the drive components are connected to the controller.

[0021] Furthermore, when the bubble generator is not required to produce bubbles, the upper vent plate moves until the vent is completely closed.

[0022] Furthermore, step 1 also includes: if not, when the time since the last adjustment of the exhaust port according to the speed is greater than T1 or the speed change is greater than V1, then the exhaust port is adjusted according to the bubble control method as described in claim 6.

[0023] Furthermore, T1 is 30 minutes, and V1 is 0.5 minutes.

[0024] The beneficial effects of this invention are as follows: This invention controls bubble size by adjusting the actual ventilation area of ​​the exhaust holes by moving the upper exhaust plate. This invention can control bubble size according to speed conditions, thereby achieving optimal drag reduction. This invention can adjust the actual ventilation area of ​​the exhaust holes according to the gas flow rate in the air supply pipeline, thereby adjusting the air supply pipeline balance and optimizing the drag reduction effect of the bubbles. This invention can eliminate attached substances near the exhaust holes by adjusting the movement of the upper exhaust plate, preventing marine organisms from entering the bubble generating device and keeping the exhaust holes unobstructed. Attached Figure Description

[0025] Figure 1 This is a perspective structural diagram of a bubble generating device according to a preferred embodiment of the present invention.

[0026] Figure 2 This is a schematic diagram of the exhaust port in a preferred embodiment of the present invention when the ventilation area is at its maximum.

[0027] Figure 3 This is a schematic diagram of the exhaust port in a preferred embodiment of the present invention when the ventilation area is at its smallest.

[0028] Figure 4 This is a schematic diagram of the vent hole in a non-ventilated state according to a preferred embodiment of the present invention.

[0029] Figure 5 This is a schematic diagram of the exhaust port structure according to a preferred embodiment of the present invention.

[0030] Figure 6 This is a schematic diagram of the upper exhaust plate according to a preferred embodiment of the present invention.

[0031] Figure 7 This is a schematic diagram of a ship air supply system according to a preferred embodiment of the present invention.

[0032] Figure 8 This is a flowchart of a bubble control method according to a preferred embodiment of the present invention. Detailed Implementation

[0033] The present invention will be described more clearly and completely below with reference to a preferred embodiment and the accompanying drawings.

[0034] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, a bubble generator 10 with controllable bubble size includes a top plate 11, an inflow curved plate 12, an outflow curved plate 13, and a side plate 14 located at the bottom of the ship; the inflow curved plate 12 and the outflow curved plate 13 are respectively located in front of and behind the top plate 11; the side plate 14 is located on both sides of the top plate 11. The bubble generator also has an air inlet 18.

[0035] A lower exhaust plate 15 is fixed between the inlet curved panel 12 and the outlet curved panel 13, and an upper exhaust plate 16 that can be moved is provided on the lower exhaust plate 15.

[0036] The upper exhaust plate 16 and the lower exhaust plate 15 have exhaust holes 17 of the same shape and the same exhaust hole spacing.

[0037] When the upper exhaust plate 16 moves, the exhaust holes of the upper exhaust plate and the exhaust holes of the lower exhaust plate vary between complete overlap and complete non-overlap.

[0038] like Figure 5 As shown, the exhaust port 17 is an oblong shape; the width of the oblong shape is 2R, and the length is L, where 3R≤L≤10R; as shown... Figure 6 As shown, along the length of the exhaust holes, the distance D between the exhaust holes is not less than L.

[0039] The waist-shaped hole consists of a rectangle in the middle and two semicircles at the two ends of the rectangle. The radius of the semicircles is R, and the width of the rectangle is 2R.

[0040] The upper exhaust vent plate is connected to a drive component 19 for moving the upper exhaust vent plate. The drive component is an electrically driven component.

[0041] The length of the vent is along the longitudinal direction of the ship. The movement direction of the upper vent plate is along the length of the vent.

[0042] The upper exhaust plate can move along the length of the exhaust holes on the lower exhaust plate. The ventilation area is maximized when the exhaust holes of the upper and lower exhaust plates completely overlap. Figure 2 As shown. When the exhaust holes of the upper exhaust plate and the lower exhaust plate do not overlap at all, the exhaust holes will not allow air to pass through, as... Figure 4As shown, when the exhaust holes of the upper exhaust plate and the exhaust holes of the lower exhaust plate change from a state of complete overlap to a state of complete non-overlap, the actual ventilation area of ​​the exhaust holes gradually decreases.

[0043] When the bubble generator is not working, the upper vent plate moves to the venting state where the vents are blocked, and the vents of the upper vent plate and the vents of the lower vent plate do not overlap at all.

[0044] A bubble control method with controllable bubble size utilizes the aforementioned bubble generator 10. During ship navigation, the vent is adjusted according to the ship's speed. The relationship between the actual ventilation area S of the vent and the ship's speed Vs is as follows: When Vs < 10, S = S min ; When 10 ≤ Vs ≤ 20, S = S min + (0.1Vs-1)·(S max - S min ); When Vs > 20, S = S max ; Where Vs is in units of sections; S max S represents the maximum ventilation area of ​​the exhaust port. min The minimum ventilation area of ​​the exhaust port; and S min >0.

[0045] In this embodiment, the vessel is a large merchant ship sailing at sea with a speed between 8 and 23 knots.

[0046] The area of ​​the hollow part between the exhaust holes of the upper exhaust plate and the corresponding exhaust holes of the lower exhaust plate is the actual ventilation area of ​​the exhaust holes.

[0047] The maximum ventilation area of ​​the vent is the area of ​​the vent. The ventilation area is maximized when the vents of the upper and lower vent plates completely overlap.

[0048] In this embodiment, the minimum ventilation area of ​​the exhaust port is πR. 2 The semi-circular exhaust holes of the upper exhaust plate and the semi-circular exhaust holes of the lower exhaust plate combine to form a circle, minimizing the ventilation area of ​​the exhaust holes. Figure 3 As shown. In other embodiments, the minimum ventilation area of ​​the vent can also be determined.

[0049] The ship uses N of the aforementioned bubble generators 10, supplied with air by one air compressor 21, where N > 1; each bubble generator corresponds to a branch 23 and a flow meter 22; specifically as follows... Figure 7 As shown; the bubble control method also includes: Step 1: Determine the maximum flow rate Q measured by the flow meter. max With minimum flow Q min Does it satisfy Q? max / Q min >1.2; If yes, proceed to step 2; if no, do not proceed to the next step. Step 2, determine whether 0.95Sx > S min Where Sx is the actual ventilation area of ​​the exhaust port of the bubble generator in the branch with the maximum flow rate x; Step 3: If not, adjust the upper exhaust plate so that Sx = S min If so, adjust the upper exhaust plate to reduce Sx by 5%; then repeat step 1.

[0050] Step 1 further includes: if not, when the time since the last adjustment of the exhaust port based on speed is greater than T1 or the speed change is greater than V1, then the exhaust port is adjusted according to the bubble control method as described in claim 6. In this embodiment, T1 is 30 minutes and V1 is 0.5 knots.

[0051] The flow meter is connected to a controller 24 that can receive signals from the flow meter and control the drive components. The drive components 19 are connected to the controller 24.

[0052] Based on the signal from the flow meter, the controller sends corresponding instructions to the drive component, causing the upper exhaust orifice plate to move, thereby adjusting the actual ventilation area of ​​the exhaust orifice.

[0053] For clarity, Figure 7 Only two bubble generators are shown in the diagram, in which case N=2.

[0054] The flowchart of the bubble control method of the present invention is as follows: Figure 8 As shown.

[0055] When the bubble generator is not needed to produce bubbles to the bottom of the ship, the upper vent plate moves until the vents are completely closed. This prevents marine organisms from entering the inner cavity of the bubble generator, thus inhibiting their growth. A unique feature of the bubble generator of this invention is its ability to be completely shut off, isolating it from seawater.

[0056] This invention controls bubble size by adjusting the actual ventilation area of ​​the exhaust vents by moving the upper exhaust vent plate. This invention can control bubble size according to flight speed conditions, thereby achieving optimal drag reduction. Furthermore, this invention can adjust the actual ventilation area of ​​the exhaust vents according to the gas flow rate in the air supply pipeline, thereby adjusting the air supply pipeline balance and optimizing the drag reduction effect of the bubbles.

[0057] When the bubble generator is not working, the vent holes of the upper vent plate and the vent holes of the lower vent plate do not overlap at all, which can prevent seawater from flowing back into the air supply pipeline and prevent marine organisms from entering the bubble generator.

[0058] This invention can adjust the bubble size according to the ship's operating conditions to achieve optimal drag reduction. It balances the gas flow in the bubble generator by adjusting the actual ventilation area of ​​the vent. Furthermore, by adjusting the movement of the upper vent plate, it can eliminate any adhering substances near the vent, ensuring unobstructed ventilation.

[0059] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A bubble control method with controllable bubble size, characterized in that, It uses a bubble generator with controllable bubble size, which includes a top plate, an inflow curved plate, an outflow curved plate, and side plates located at the bottom of the ship; the inflow curved plate and the outflow curved plate are respectively located in front of and behind the top plate; the side plates are located on both sides of the top plate; a lower vent plate is fixed between the inflow curved plate and the outflow curved plate, and a movable upper vent plate is provided on the lower vent plate; the upper vent plate and the lower vent plate have vents of the same shape and the same spacing between the vents. The distance between the upper exhaust vent plate and the lower exhaust vent plate varies between complete overlap and non-overlap when the upper exhaust vent plate moves. The exhaust vents are oblong. The oblong vent consists of a rectangle in the middle and two semicircles at the ends of the rectangle. The radius of the semicircles is R, the width of the oblong vent is 2R, and the length is L, where 3R≤L≤10R. The distance between the exhaust vents is not less than L along the length of the exhaust vent. The upper exhaust vent plate is connected to a drive component for moving the upper exhaust vent plate. The control method includes: Step 1: Adjust the size of the exhaust port according to the ship's speed during navigation. The relationship between the actual ventilation area S of the exhaust port and the ship's speed Vs is as follows: When Vs < 10, S = S min ; When 10 ≤ Vs ≤ 20, S = S min + (0.1Vs-1)·(S max - S min ); When Vs > 20, S = S max ; Where Vs is in units of sections; S max S represents the maximum ventilation area of ​​the exhaust port. min The minimum ventilation area of ​​the exhaust port; and S min >0; Step 2: Flow Balance Control: The ship uses N bubble generators, supplied with air by one air compressor, where N > 1; each bubble generator corresponds to one branch and one flow meter; the flow balance control includes the following steps 1-3: Step 1: Determine the maximum flow rate Q measured by the flow meter. max With minimum flow Q min Does it satisfy Q? max / Q min >1.2; If yes, proceed to step 2; if no, when the time since the last adjustment of the exhaust hole size based on the ship's speed is greater than 30 minutes or the speed change is greater than 0.5 knots, adjust the exhaust hole size according to the aforementioned method based on the ship's speed. Step 2, determine whether 0.95Sx > S min Where Sx is the actual ventilation area of ​​the exhaust port of the bubble generator in the branch with the maximum flow rate x; Step 3: If not, adjust the upper exhaust plate so that Sx = S min If so, adjust the upper exhaust plate to reduce Sx by 5%; then repeat step 1.

2. The bubble control method for controllable bubble size as described in claim 1, characterized in that, The maximum ventilation area of ​​the vent is the area of ​​the vent.

3. The bubble control method for controllable bubble size as described in claim 1, characterized in that, The minimum ventilation area of ​​the exhaust port is πR. 2 .

4. The bubble control method for controllable bubble size as described in claim 1, characterized in that, The flow meter is connected to a controller that can receive signals from the flow meter and control the drive components, and the drive components are connected to the controller.

5. The bubble control method for controllable bubble size as described in claim 1, characterized in that, When the bubble generator is not required to produce bubbles, the upper vent plate moves until the vent is completely closed.

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