Air release unit and vessel

Abstract

An air release unit and a boat comprising the air release unit for installation in a hull of a boat having a raised floor. The air release unit is to be installed to one side or the other of the keel and thus provided in port and starboard variants. The air release unit comprises a cavity defined by a top wall, a rear wall and a pair of side walls diverging from a nose of the cavity to an aft end, wherein an inboard side wall extends downward to engage the hull at an inboard junction, an outboard side wall extends downward to engage the hull at an outboard junction, and the inboard junction is lower than the outboard junction, the air release unit further comprises a deflector plate spanning the cavity between the inboard side wall and the outboard side wall, and the deflector plate is angled relative to a line joining the inboard junction and the outboard junction in a beam direction.

Description

Technical Field

[0001] This application relates to an air release unit (ARU) for air lubrication of a ship, and more particularly to an air release unit suitable for a ship with a raised bottom plate. This application also relates to a ship including the air release unit. Background Technology

[0002] To reduce the energy required for ship propulsion, various solutions have been proposed to reduce ship drag. Pressure or wave drag can be reduced through optimized hull design. For modern commercial ships, this can be further optimized, for example, by scaling, but this may affect other factors such as stability and maneuverability. Another source of drag is frictional drag, caused by shear forces on the ship's surface and the no-slip conditions employed. This is currently the main cause of drag in commercial ships.

[0003] In recent years, methods to reduce frictional drag by using air at the hull-water interface have attracted attention. Early solutions involved creating a large cavity beneath the hull to form an air cushion, allowing the ship to float or glide with lower frictional resistance. However, due to the ship's pitching and rolling, coupled with the entrainment effect of the water, air continuously escapes from the cavity, and the actual effect falls short of theoretical expectations. This escaped air is wasted and must be replaced, requiring a significant amount of energy to pump the air back to the pressure needed at the hull bottom.

[0004] A more efficient alternative is an air lubrication system that continuously supplies air to the hull. The supplied air is designed to form an air layer at the hull, acting as an interface between the hull and water to reduce frictional drag. The system's efficiency depends on the ratio of reduced propulsion power to the power required for continuous air supply. Without being bound by theory, uniform air distribution is believed to be key to improving this efficiency. A large-area microbubble blanket covering the hull is believed to significantly improve lubrication compared to the same number of large microbubbles. Furthermore, the Kelvin-Helmholtz mechanism is believed to efficiently generate these microbubbles.

[0005] The contents of WO2013125951 and WO2015133899 are incorporated herein by reference in their entirety, and they disclose systems and boats using microbubbles. These patent disclosures mention that by setting a small open cavity and injecting air into the cavity at near-hydrostatic pressure, a flat air-water interface can be formed at the boat's bottom height, achieving efficient air lubrication of the boat's flat bottom. At this interface, a flow of microbubbles is generated due to Kelvin-Helmholtz instability, and the microbubble flow escapes from the rear end of the cavity, thus mixing the air with the water. This cavity can be referred to as an air release unit, which is designed to release air in the form of microbubbles rather than maintaining air in the form of an air cushion. Guidance is provided regarding the required cavity size. The cited disclosures also illustrate how to configure deflector plates to maintain air within the cavity and assist in maintaining the continuous and stable generation of microbubbles. This application relates to air lubrication using an air release unit for generating microbubbles, and does not relate to configurations such as air cushion cavities.

[0006] It should be understood that the cavity size of the air release unit is much smaller than that of a ship, but the area that can be lubricated can be several times the interfacial area. The cavity size mainly depends on the interfacial length required to achieve stable microbubble generation, and the interfacial length itself depends on the ship speed. Kelvin-Helmholtz instability requires a certain length of shear force between the two fluids, similar to the length of the wind zone required for wind to create white waves on water. For typical operating conditions of large ships, an air-water interfacial length of only 1 meter is sufficient to release microbubbles from the interface. Because of its compact configuration, this air release unit can be easily integrated into the hull structure without significantly affecting lateral or longitudinal stiffness. This air release unit can also be used to retrofit existing ships to improve efficiency.

[0007] Importantly, after microbubbles are generated, it is crucial to ensure their effective distribution within the hull and retention within the boundary layer to maximize their utility. In this regard, the layout and orientation of the air release unit are critical. An alternative air release unit for vessels with flat bottoms is proposed in WO2020 / 231264. This air release unit has sidewalls that extend to the rear end of the cavity. This configuration has been shown to significantly improve the coverage width of microbubbles on flat bottoms. The cavity design is orientation-insensitive. When designing a vessel or retrofitting an existing vessel's cavity, the orientation must be chosen to best correspond to the expected hull flow state associated with given operating conditions. However, it should be understood that no vessel always operates at the same speed and draft, and weather conditions can mean that a vessel can travel long distances with a slight heel. The cavity proposed in WO2020 / 231264 has been found to operate effectively, even when the flow lines along the hull are not aligned with the centerline of the air release unit. Using this air lubrication system, fuel consumption reductions of up to 10% have been achieved.

[0008] The aforementioned type of air release unit offers improved efficiency and utilizes relatively low energy to lubricate the hull. However, existing air release units are only suitable for installation in flat-bottomed boats. There is a need to provide an air lubrication system that can be installed in boats with other hull shapes. Utility Model Content

[0009] According to this application, an air release unit is provided for installation in the hull of a vessel with a raised bottom plate. The air release unit is installed to one or the other side of the keel and is thus provided in port and starboard versions. The air release unit includes a cavity defined by a top wall, aft wall, and a pair of side walls extending from the nose of the cavity to the rear end, wherein the inner side wall extends downward to engage the hull at an inner joint, and the outer side wall extends downward to engage the hull at an outer joint, and the inner joint is lower than the outer joint. The air release unit also includes a deflector plate that spans the cavity between the inner and outer side walls, and the deflector plate is angled relative to the line that engages the inner and outer joints in the beam direction. In the following, in the vessel's frame of reference, the keel direction will correspond to the longitudinal direction and centerline of the vessel. The beam direction is the transverse direction of the vessel and is perpendicular to the keel direction. The references to horizontal and vertical refer to the static state of the vessel when both the keel and beam directions are horizontal. Reference can also be made to the hull shell, which represents, for example, the theoretical outer contour of the hull in the absence of cavities or air release units. Therefore, the line that joins the inner and outer joints in the beam direction is part of the hull shell.

[0010] While existing air release units disclosed in WO2020 / 231264 work well on flat-bottomed boats, they do not realize their full potential when integrated into boats with raised bottom plates. In this context, a boat with a raised bottom plate is one in which the hull is raised from the keel in the beam direction. For the seagoing vessels to which this application is applicable, this elevation is typically from 2 to 8 degrees. It should be understood that other boats, such as sailboats, can have much higher elevation angles. It has been observed that, when mounted on a raised bottom plate, existing air release units release air from the highest point outside the rear end of the cavity. This air disrupts the fluid shear at the interface, instead escaping as a convection that peels away from the air release unit in a rearward direction without creating microbubbles on the hull surface. The interfacial surface area of ​​the air release unit, which no longer supports fluid shear, increases proportionally to the elevation angle of the bottom plate.

[0011] According to this application, by adapting the sidewalls and deflector plates to the raised bottom plate, the air-water interface can be maintained more stably, and a better transition between the hull and the cavity can be achieved. Importantly, the deflector plates no longer extend parallel to the bottom of the hull in the beam direction as was consistently considered in previous designs. By tilting the deflector plates relative to the outer shell, the generation of turbulence can be reduced or avoided, and a wider microbubble carpet can be achieved by ensuring that the fluid is sheared over a larger area of ​​the cavity.

[0012] In one embodiment, the deflector plate may extend horizontally in the beam direction. A horizontal deflector plate helps prevent the formation of air plumes and maximizes the area available for fluid shear. However, there may be reasons to have the deflector plate form an angle at the midpoint between the hull's horizontal and elevation angles. This may be desirable to allow control of the interface plane. Alternatively, the deflector plate may be angled slightly opposite to the hull's elevation angle. In this embodiment, the deflector plate is at + / - 2 degrees relative to the horizontal direction in the beam direction.

[0013] In this embodiment, the deflector plate extends horizontally along the keel direction. Therefore, the deflector plate can be generally located in the horizontal plane. However, it should be understood that the deflector plate can also be angled along the keel direction, for example, parallel to the hull, especially if the hull itself has a rocker or the ship is designed to operate with a certain degree of trim. The deflector plate can be angled in the aft direction to increase the propagation height within the cavity. Alternatively, the deflector plate can be angled slightly downward in the aft direction to help guide microbubbles out of the cavity. In this embodiment, the deflector plate is at + / - 2 degrees relative to the horizontal direction in the keel direction.

[0014] Additionally, in this embodiment, the top wall of the cavity may extend horizontally in the beam direction and / or keel direction. Typically, the top wall of the cavity is not critical for generating microbubbles at the air-water interface plane, as it is influenced by sufficient cavity volume. However, if the cavity has a top wall horizontal in the beam direction, existing cavities can be used, where only the lower portions of the aft and side walls need to be adapted for hull integration.

[0015] In this implementation, the sidewalls can be vertical. In this case, for a given transverse cross-section of the cavity, the sidewalls can be parallel to each other. The sidewalls can be vertical along their entire height, extending to the corresponding inner and outer joints with the hull. In this implementation, the sidewalls are vertical at least above the deflector plate. Below the deflector plate, the inner sidewalls may have a scarf-like portion extending further inward to meet the inner joint, the scarf-like portion extending from the adjacent wave deflector to the inner joint. The scarf-like portion can begin at a height on the sidewall corresponding to the position of the wave deflector. This is intended to include a position just above or below the position of the wave deflector, for example, within a vertical distance of up to 50 mm, 30 mm, or 10 mm from the wave deflector. In the longitudinal direction, the scarf-like portion can begin at the nose of the cavity and extend to the rear end of the cavity, or it can extend only in the middle portion of the cavity.

[0016] The purpose of the scarf-shaped portion is to guide the flow through the hull toward the opening of the cavity without introducing additional turbulence. Preferably, the scarf-shaped portion should guide the flow through the hull to traverse the cavity horizontally. The maximum width of the scarf-shaped portion in the beam direction will depend on the hull's rise and the degree of divergence of the cavity's sidewalls. In embodiments, the maximum width may be less than 300 mm, less than 200 mm, or less than 100 mm. In embodiments, the width of the scarf-shaped portion may be less than 300 mm. The minimum width may be at least 50 mm, at least 20 mm, or at least 10 mm. The scarf-shaped portion may be a single plate having an intermediate angle between the hull's rise angle and the inclination of the sidewalls. The intermediate angle may be in the range of 10° to 70° measured from the hull's rise angle, preferably between 10° and 60°, and more preferably between 10° and 40°. In embodiments, the scarf-shaped portion may be inclined at 10° to 70° relative to the rise of the hull's bottom plate. The mid-angle can also vary in the keel direction, for example, so that the horizontal projection of the scarf-shaped part remains constant in the keel direction.

[0017] The scarf-shaped portion can also be bent in the beam direction. In one embodiment, the scarf-shaped portion can have a simple bend that is asymptotic with respect to the inner sidewalls of both the housing and the cavity, thus forming an outward bend between the two surfaces. Alternatively, the scarf-shaped portion can be a complex bend with an inflection point, such that it horizontally engages the sidewall of the cavity, ideally just below and parallel to the deflection plate.

[0018] The air release unit can be incorporated into the vessel in any suitable manner during construction or retrofitting. In one embodiment, the air release unit includes a base plate surrounding the cavity. This can further facilitate integration with the hull. The base plate can completely surround the cavity on all sides and has peripheral edges. The base plate may have sloping portions corresponding to raised bottom plates of the hull, at least at its peripheral edges, which are the points where it connects to the hull. The base plate can extend around the cavity and around any scarf-like portions or transition plates that may be present. The base plate itself can include all necessary transition portions between the hull and the cavity. Its thickness can preferably correspond at least to the thickness of the surrounding hull. In a preferred embodiment, the base plate is integrally formed by the abutment of its periphery with the peripheral edges of openings formed in the hull. In the presence of the base plate, inner and outer joints can be located on the base plate, i.e., at the locations where the sidewalls meet the hull shell.

[0019] The projected shape of the cavity in the horizontal plane can be the same as existing cavities, for example, a diverging sawtooth shape. However, it should be understood that it is impossible to discern the horizontal cross-sectional shape of the cavity near the hull. For the purposes described below, we can consider a horizontal cross-section passing through the cavity at the location of the deflector plate. In an embodiment, the sidewalls are symmetrical about the centerline passing through the nose at this cross-section. The sidewalls can also remain symmetrical above the deflector plate and relative to the top plate. In this way, the cavity can have the same shape and size as existing cavities within the hull or at least above the deflector plate. It can deviate from existing cavities only at the location where the deflector plate intersects with the hull. In an embodiment, the sidewalls diverge from the nose all the way to the rear of the cavity, preferably having a constant divergence angle in the rear half of the cavity, ranging from 2 degrees to 20 degrees, preferably from 2 degrees to 10 degrees, and optionally from 2 degrees to 6 degrees. In an embodiment, the sidewalls diverge at such a constant value over a preferred portion of the cavity's length. The following will further explain why cavity walls that are straight for most of their length may be advantageous.

[0020] Additionally, in one embodiment, the horizontal cross-section of the cavity at the location of the deflector plate has a centerline passing through the nose, and this centerline is parallel to the keel. Therefore, the cavity is parallel to the keel, meaning the centerline of the cavity is parallel to the ship's centerline. Alternatively, the centerline of the cavity may not be parallel to the keel. Specifically, the centerline of the cavity may be offset outward from the keel in a rearward direction. The angle of offset may be between 1 and 10 degrees, or between 2 and 5 degrees.

[0021] In another optional configuration, the air release unit can be arranged such that its plane of symmetry is perpendicular to the ship's raised bottom plate. In other words, the cavity, which would otherwise be symmetrical, can be tilted at an angle corresponding to the ship's raised angle. This has the advantages that a conventional cavity can be installed in the hull, and only the deflector plate needs to be adjusted to different angles, such as a horizontal angle. This solution can be conveniently used for low raised angles, such as from 1 degree to 4 degrees or from 1 degree to 3 degrees.

[0022] The rear wall of the cavity can slope downwards to engage the hull at a point defining the rear end of the cavity. In one embodiment, a transition plate can be provided between the rear wall and the hull. The rear wall can terminate at the rear of the deflector plate and abut against the transition plate, which transitions to alignment with the hull. The rear wall can be planar and angled relative to the top wall of the cavity. The transition plate can be planar and have an inclination different from that of the rear wall and different from that of the hull. The transition plate can engage the hull and / or the rear wall at a line extending at an angle to the beam direction. In one embodiment, it engages the hull at an angle that extends diagonally rearward from the outer engagement to the inner engagement. The transition plate can form part of the bottom plate surrounding the cavity. The transition plate can also abut against a scarf-like portion.

[0023] The air release unit can have any suitable size, provided that it can stably generate microbubbles within the cavity through operation via Kelvin-Helmholtz instability. In an embodiment, the cavity can have a maximum length Lc from the nose to the rear end, with the maximum length Lc being between 1 m and 10 m. For low-speed operation, the cavity can be in the range of 1 m to 5 m. For higher-speed vessels, the cavity length can preferably be between 4 m and 8 m. The maximum width Wc of the cavity in horizontal projection can be between 50 cm and 180 cm, preferably between 80 cm and 150 cm. It should be understood that the current definition of the cavity includes any scarf-like portion, and the width of the cavity at or above the deflector plate will be less than these values. Additionally, the cavity can have a maximum height Hc, which is measured as the vertical projection between the lowest point of the deflector plate and the highest point of the top wall, and is 10 cm to 70 cm, preferably 20 cm to 60 cm or 30 cm to 50 cm. It was also found that the relationship between these dimensions is important, and that cavities can have ratios Lc / Hc ranging from 6:1 to 15:1, Wr / Hc ranging from 1.3:1 to 5:1, and / or Lc / Wr ranging from 3.5:1 to 7:1.

[0024] In existing systems designed for flat-bottomed boats, the interface plane establishing the air-water interface essentially corresponds to the hull's outer shell. For boats with raised bottom plates, the actual location of any interface is less clearly defined. However, it should be understood that it will always be below the deflector plate, and in the following text, the area within the cavity but below the deflector plate will be referred to as the interface plane in a broader sense. Thus, the location of the deflector plate can be considered critical to the location of the interface. In embodiments, the deflector plate is arranged with a minimum distance from the hull shell, which should be between 10 mm and 50 mm, preferably between 15 mm and 30 mm, or approximately 20 mm. This distance can be defined at the closest point between these two planes.

[0025] Similar to existing air release units, the deflector plate can be spaced from the sidewalls by an air gap, wherein at least 60%, preferably at least 80%, of their common boundary is between 10 mm and 50 mm, more preferably between 15 mm and 25 mm, thereby allowing air from the upper part of the cavity to reach the interface plane below the deflector plate. In an embodiment, the deflector plate and the sidewalls are spaced from the sidewalls by an air gap between 10 mm and 50 mm.

[0026] The deflection plate has been mentioned in the singular above. However, it is not excluded that multiple sub-plates or small pieces may exist together to form a deflection plate. A small piece may be a strip that spans the cavity from one sidewall to another. The small piece may be flat, angled, or louvered, and may include all or any shapes shown in WO 2015133899. The deflection plate may also be provided with openings, thereby allowing air to enter the interface area from the cavity through these openings.

[0027] The air release unit may also include an air inlet in closed communication with the cavity. The air inlet can be located in any position, including through a sidewall or in the nose section. In one embodiment, the air inlet may be located in the top wall at a distance Li from the inlet of the nose section of the cavity. Multiple air inlets may be provided. The air inlets may be connected to a compressed air source capable of introducing a volume of air at a rate sufficient to maintain a stable interface and stable microbubble delivery during ship operation at a specified speed, under hydrostatic pressure corresponding to the interface region.

[0028] The air release unit can be manufactured with configurations suitable for a range of vessels, such as those with raised bottom plates ranging from 2 to 8 degrees, preferably from 3 to 6 degrees. Preferably, it is manufactured with a specific configuration of carefully selected dimensions that are optimal for a particular raise angle. Each air release unit can be a port-side air release unit or a starboard-side air release unit.

[0029] This disclosure also relates to a vessel having a keeled hull, wherein the hull is raised on either side of the keel and has a plurality of air release units as described above or below, each air release unit being mounted in the hull on the port or starboard side of the keel.

[0030] The ship may have an air release unit installed in the hull at an angle of 2 to 8 degrees, preferably 3 to 6 degrees, relative to the horizontal plane.

[0031] These air release units can be distributed on the hull of the vessel in any suitable manner to achieve thorough lubrication of all relevant surfaces of the hull. In one embodiment, the vessel may have at least a first air release unit and a second air release unit on each side of the keel. The first and second air release units may be mounted such that they are equidistant from the keel. Alternatively, the air release units may be distributed equidistantly along either side of the keel. Alternatively, the air release units may be mounted in a V-shaped configuration to radiate from the hull of the vessel. Attached Figure Description

[0032] The features and advantages of this application will be understood by referring to the accompanying drawings of the following exemplary embodiments, in which:

[0033] Figure 1 A schematic side view of a ship according to the prior art is shown;

[0034] Figure 2 As shown below Figure 1 ship;

[0035] Figure 3 The section cut along direction III-III is shown. Figure 2 A sectional view of the ship;

[0036] Figure 4 An air release unit according to the prior art is shown in a three-dimensional view;

[0037] Figure 5 A partial view of a ship according to a first embodiment of this application, viewed from below, is shown;

[0038] Figure 6 The image shown is a section cut along the VI-VI direction. Figure 5 A sectional view of the ship;

[0039] Figure 6A It shows Figure 6 Enlarged view of the port side air release unit;

[0040] Figure 6B and Figure 6C It shows the relationship with Figure 6AThe corresponding enlarged image, along Figure 5 The sections VIB-VIB and VIC-VIC are cut off in the middle;

[0041] Figure 7 It shows the corresponding Figure 6A A modified view of the port side air release unit;

[0042] Figure 8 It shows the corresponding Figure 6A A view of the second variant of the port side air release unit;

[0043] Figure 9 A horizontal cross-sectional plan view above the deflector plate is shown, taken through the port side air release unit according to the second embodiment of this application;

[0044] Figure 10 It passes through along the XX direction. Figure 9 A cross-sectional view of the air release unit;

[0045] Figures 11A-11C It shows Figure 10 Three variations of the air release unit; and

[0046] Figure 12A and Figure 12B It shows the corresponding Figure 5 The lower view shows two optional configurations of the air release unit. Detailed Implementation

[0047] Figure 1 A schematic side view of a vessel 1 according to the prior art is shown. The vessel 1 has a hull 2 ​​with a bottom surface 3 that extends from the bow 4 to the stern 5. Figure 2 This is a view from the bottom of ship 1.

[0048] like Figure 2 As shown, the bottom surface 3 of the vessel 1 includes a row of five air release units 6, arranged adjacent to each other across the width of the vessel 1. The air release units 6 are connected to a compressor 12 via an air supply pipe 11, which supplies air to the air release units 6 under the control of a controller 15. It should be understood that additional compressors may be provided. The air release units 6 are arranged to distribute microbubble blankets 14 on the bottom surface 3 of the vessel 1. The air release units 6 are all identical and symmetrical, having mutually parallel planes of symmetry SP parallel to the vessel's centerline C, with two air release units 6 located on the port side and two on the starboard side. The central air release unit 6 is located on the vessel's centerline.

[0049] Figure 3 It is along Figure 2A schematic cross-sectional view taken through hull 2 ​​in direction III-III. In this view, it can be understood that the bottom surface 3 of hull 2 ​​is flat, at least over most of the width Wv of the ship 1. In the illustrated embodiment, hull 2 ​​is formed having an inner hull 2A and an outer hull 2B, although such air release units could also be installed in a single hull. Air release units 6 are shown in the cross-sectional view as having sidewalls 18 that span the gap between the inner hull 2A and the outer hull 2B. They are located in the flat area of ​​the bottom surface 3 such that their plane of symmetry SP is perpendicular to the bottom surface 3 and aligned with the ship's centerline CL.

[0050] Figure 4 A perspective view of an air release unit 6 is shown, configured as an integral module forming a cavity 33, which can be fitted into the hull 2 ​​of the boat 1. The air release unit 6 includes a sidewall 18 extending from the nose 22 to the rear end 21 of the cavity. A top wall 19 extends across the sidewall 18 at its upper edge, thereby defining the cavity 33. The sidewall 18 is supported by a lower joint 29 on a base plate 17, which can be welded to the bottom surface 3 of the boat 1 around its perimeter 31. The sidewall 18 defines an opening 20 that follows the hull of the hull 2, substantially flush with the flat bottom surface 3 of the boat 1. In use, the opening 20 forms a smooth air-water interface plane, in which air is mixed into the water due to the Kelvin-Helmholtz shearing effect. Microbubbles mixed with water at the interface exit the cavity at the rear end 21 to smoothly transition from cavity 20 to the downstream bottom surface 3, and travel unrestricted along the bottom surface 3 in the direction of the stern 5 within the boundary layer. A concave, downwardly sloping rear wall 27 extends downward from the top wall 19 to the rear edge 21 to guide air within the cavity 33 in a smooth flow pattern to the exit point at the rear end 21. The rear wall 27 begins at its intersection with the top wall 19, located at a distance Lr from the rear wall of the rear end 21. The cavity 33 has a length Lc, a width Wc at its widest point, and a height Hc.

[0051] The nose 22 is wedge-shaped, and the sidewalls 18 continue to smoothly diverge at a decreasing rate in the rearward direction from the nose 22 to the rear end 21. In the rear half of the cavity 33, the sidewalls separate, each sidewall separated at a constant angle of approximately 5 degrees. The air inlet 23 is located in the top wall 19. The air inlet 23 is connected to the compressor 12 via an air supply pipe 11.

[0052] Within cavity 33, deflector plate 25 extends across opening 20 between sidewalls 18. Deflector plate 25 is spaced from the sidewalls by gap 26, which allows air to flow from above to below deflector plate 25. It is supported at intervals along the sidewalls 18 by brackets 28. Deflector plate 25 provides back pressure to the system, enabling air to fill cavity 33 while preventing the generation of unstable waves within cavity 33 during shearing. Additionally, deflector plate 25 minimizes the resistance of cavity 33 while shutting off the air supply.

[0053] The deflector plate 25 is located above the interface plane of the cavity 33 to allow undisturbed water flow through the cavity 33 during the ship's sailing speed. When the cavity 33 is filled with air, the deflector plate 25 is separated from the water surface. The deflector plate 25 also helps to maintain the stability of the Kelvin-Helmholtz interface during the ship's rolling motion. Although the precise thickness of the air-water interface will depend on operating conditions, it can be considered to occupy the area between the deflector plate 25 and the opening 20.

[0054] Figure 5 The bow 104 of the vessel 100, viewed from below, is shown, and the bow is equipped with an air release unit 6 according to this application. The same reference numerals are used to indicate... Figures 1 to 4 The same features are shown. Two port-side air release units 6A and two starboard-side air release units 6B are positioned in a V-shape on either side of the centerline CL. The deflector plate 25 can be seen within the cavity 33 of the air release units 6 and the bottom plate 17.

[0055] Figure 6 It shows the direction VI-VI passing through Figure 5 The sectional view of the ship 100 corresponds to the rear edge of the deflector plate 25. It should be noted that... Figure 5 It is viewed from below, and Figure 6 This is an upright view, with the port and starboard sides inverted. In this view, it can be seen that the ship 100 has a hull 102, which has a bottom 103. The bottom 103 has a raised bottom plate with port stern plates 103A and starboard stern plates 103B inclined at an angle θ on either side of the keel 107. It can also be seen that the air release units 6 are oriented vertically and parallel to each other in their plane of symmetry SP. The deflector plate 25 can be considered horizontal. Therefore, the port air release unit 6A differs from the starboard air release unit 6B, at least at their positions where they intersect with the hull 102. Above the deflector plate 25, the two air release units 6 are identical to each other and... Figure 4 The same as shown.

[0056] Figure 6A yes Figure 6An enlarged view of the port side air release unit 6A. The air release unit 6A has an inner sidewall 18A and an outer sidewall 18B. The inner sidewall 18A intersects with the hull shell 102' at an inner joint 29A, and the outer sidewall 18B extends downward to engage with the hull shell 102' at an outer joint 29B. It should be noted that the bottom plate 17 of the air release unit 6A is joined to the hull 102 around its peripheral edge 31 in a mating joint. Therefore, the inner joint 29A and the outer joint 29B are located on the bottom plate 17 at the location of the hull shell 102', rather than on the hull 102 itself.

[0057] The inner joint 29A is vertically lower than the outer joint 29B by an amount corresponding to the lift θ of the bottom plate over the width of the air release unit 6 between the inner and outer joints 29A and 29B. The deflector plate 25 is horizontal and spaced vertically from the outer joint 29B by a distance T. This is also the minimum distance between the deflector plate and the hull shell 102', which is an imaginary line passing through the cavity 33 of the hull 102. This distance T can also represent the thickness of the air-water interface below the deflector plate 25. In the illustrated embodiment, this distance is 5 cm. The deflector plate 25 is supported by and spaced apart from the sidewalls 18A and 18B, with a gap 26 between 10 mm and 50 mm maintained between the deflector plate and the sidewalls along their common boundary, thereby allowing air from the upper part of the cavity 33 to reach the interface plane below the deflector plate 25.

[0058] Figure 6B It is observed along the VIB-VIB direction. Figure 5 Enlarged view of the port side air release unit 6A. Figure 6B and Figure 6A Similarly, but cut off through a portion of the nose 22 of the cavity 33 located in front of the air inlet 23. In this portion, the sidewalls 18A and 18B are significantly closer together, with... Figure 6A Compared to the previous case, the inner sidewall 18A is farther from the centerline CL, while the outer sidewall 18B is closer to the centerline CL. Consequently, the outer joint 29B is also more vertically oriented than... Figure 6A The situation is low. Since the deflection plate 25 is horizontal, its vertical distance from the outer joint 29B is larger at this part that passes through the cavity 33.

[0059] Figure 6C It is observed along the VIC-VIC direction. Figure 5 Enlarged view of the port side air release unit 6A. Figure 6C Similar to Figure 6A and Figure 6B However, it is cut off at the rear end 21 of the cavity 33 behind the deflection plate 25. The vertical position of the deflection plate is indicated by line 25'. In this part, the sidewalls 18A and 18B are more... Figure 6ASlightly further away, with the inner sidewall 18A closer to the centerline CL and the outer sidewall 18B further away from the centerline CL. As a result, the outer joint 29B is higher in the vertical direction than... Figure 6A The situation is as follows. It should be understood that, since the outer sidewall 18B radiates from the nose 22 towards the rear end, the outer joint 29B is located at its highest point in this part. As a result, air, especially the generated microbubbles, tends to leave the cavity 33 more at this location than at other locations along the rear end of the cavity. However, the presence of the horizontal deflector 25 promotes more stable shearing and microbubble generation across the entire width of the cavity 33 compared to the case where the cavity 33 was installed perpendicular to the hull of the ship.

[0060] Figure 7 It shows the corresponding Figure 6A A modified view of the air release unit 6A. Except for the deflection plate 25 being slightly tilted upwards at an angle α toward the inner end, all other aspects are the same as... Figure 6A The implementation method is the same. In this figure, for illustrative purposes, this tilt is exaggerated and can be as small as 1 or 2 degrees. The tilt of the deflector plate 25 helps to direct the generation and flow of microbubbles toward the inner sidewall 18A, thereby counteracting the tendency of the microbubble plume to leave the outer junction 29B at the rear end 21 of the cavity 33. Although not shown, the deflector plate may also be tilted in the front-back direction and / or may be non-planar, for example, having complex bends.

[0061] Figure 8 It shows the corresponding Figure 6A A view of a second variant of the air release unit 6A. In this variant, the entire cavity unit is rotated by an angle θ, except that the deflector plate 25 remains horizontal, to keep its plane of symmetry SP perpendicular to the hull 102. Figure 8 In the text, this bias is exaggerated for the purpose of explanation. Figure 8 The advantage of the variation shown is that the bottom plate 17 remains perpendicular to the side walls 18A and 18B, and both have equal lengths. Therefore, the complete air release unit 6A can be the same as the air release unit used in a flat-bottomed boat; the only requirement is that the position and inclination of the deflector plate must be adapted to the rise of the bottom plate θ. For example, in Figure 7 In variations, the deflector plate 25 may be angled not to the horizontal direction, but also to the front-back direction, and / or may be non-planar, for example, having complex bends. The deflector plate 25 can be angled by adjusting the position of the bracket holding it to the side walls 18A, 18B, or by setting wedges, spacers, or by making appropriate adjustments between such brackets and the deflector plate 25.

[0062] Figure 9A plan view of an air release unit 106A according to an alternative embodiment of this application is shown. In this embodiment, with Figure 4 The same features associated with the unit will be given similar reference numerals preceded by 100. In this case, reference numerals are given for different embodiments rather than variations, because additional structural features are added rather than simply reorienting existing parts of the unit.

[0063] Figure 9 It is the air release unit located on the port side of the ship's centerline CL, which is raised from the bottom. It should be understood that a mirror-symmetrical starboard configuration can also be provided. Figure 9 A horizontal sectional view is shown, passing through unit 106A, above deflection plate 125, and intersecting with inner sidewalls 118A and 118B, and with rear wall 127 to expose cavity 133. Deflection plate 125 is supported from sidewalls 118A and 118B by brackets 128. A scarf-like portion 135 is located inside the cavity. Behind rear wall 127, a transition plate 138 extends to the rear end 121 of cavity 133. In this embodiment, transition plate 138 is planar and connects to rear wall 127 at a line extending diagonally rearward in the outward direction. Base plate 117 surrounds the entire cavity.

[0064] Figure 10 It passes through in the XX direction. Figure 9 A cross-sectional view of the air release unit 106A, viewed from the rear of the cavity 133. Figure 10 The figure also shows a portion of the hull 102 of the ship 100, where the air release unit 106A is installed. A section of the hull is also shown in the figure. Figure 9 The plane IX-IX. For example... Figure 6 As shown, the port array plate 103A is tilted at an angle θ relative to the horizontal. The deflection plate 125 is horizontal. Above the deflection plate 125, the air release unit 106A and Figure 4 and Figure 6 The air release unit shown is the same.

[0065] In this view, the scarf-shaped portion 135 can be seen extending downwards from the inner sidewall 118A to engage with the hull shell 102' at the inner joint 129A. The outer sidewall 118B directly engages with the hull shell 102' at the outer joint 129B. Figure 5 and Figure 6 Similar to the first embodiment shown, the inner joint 129A is lower than the outer joint 129B in the vertical direction. However, in this case, it is located further inward than the outer joint 129B and further away from the plane of symmetry SP of the cavity 106A. In this document, the plane of symmetry SP is considered to be the plane of symmetry of the portion of the cavity 133 located above the deflection plate 125.

[0066] In this embodiment, the scarf-shaped portion 135 is planar and inclined at an angle β of approximately 40 degrees relative to the bottom plate 117 and the port array plate 103A. The scarf-shaped portion facilitates smooth flow from the hull 102 into the boundary area within the cavity 133 located below the deflector plate 125. A transition plate 138 is also visible within the cavity 133, extending between the rear end 121 of the cavity 133 and the rear wall 127, the rear end 121 being aligned with the hull shell 102'.

[0067] Figures 11A to 11C Three variations of the air release unit 106A are shown, including optional configurations of the base plate 117, the scarf-shaped portion 135, and the transition plate 138. The remaining portion of the air release unit 106A, above and including the deflection plate 125, remains unchanged. Figure 11A In the figure, the scarf-shaped portion 135 is bent into an outwardly convex shape, which is rotated through an angle corresponding to (90+θ) to smoothly transition from the bottom plate 117 to the vertical portion of the side wall 118A. The inner joint 129A can be defined as the point where the scarf-shaped portion 135 coincides with the hull shell 102'. The transition plate 138 is not shown in the figure, but it can also be bent in a similar manner to the scarf-shaped portion 135.

[0068] exist Figure 11B In a variation, the scarf-shaped portion 135 is provided with a complex bend that rotates horizontally to engage the inner sidewall 118A vertically. Thus, the cavity 133 has a portion located below the deflector plate 125, which extends horizontally inward at or near the level of the deflector plate 125. This can alternatively be viewed as a bottom plate portion recessed within the raised bottom plate of the port array plate 103A, which is partially horizontal in the area sufficient to mount the air release unit.

[0069] exist Figure 11B In this variant, cavity 133 is entirely within the hull. According to... Figure 11C In an alternative variation, the bottom plate 117 of the outer sidewall 118B adjacent to the air release unit 106A is adapted to form a horizontal portion that extends outward beyond the hull shell 102' and is positioned just below the level of the deflector plate 125. This can alternatively be viewed as a bottom plate portion projecting from the raised bottom plate of the port array plate 103A, which is partially horizontal in the area sufficient to mount the air release unit.

[0070] exist Figure 10 , Figure 11A , Figure 11B and Figure 11CIn all the variations shown, the bottom plate 117, the scarf-like portion 135, and the transition plate 138 can be separate and different plates, or they can be a region of the same bottom plate 117 surrounding the cavity 133 and providing an optimal transition between the raised bottom plate and the cavity 133 and its deflection plate 125 to ensure smooth inflow, effective microbubble formation, and smooth outflow of the wide microbubble blanket through the hull 102. Specifically, in Figure 11B and Figure 11C In a variant, the base plate 117 can form a transition between the raised base plate and the horizontal platform that completely surrounds the cavity area where the deflection plate 125 is located.

[0071] exist Figure 5 In the embodiment shown, two port-side air release units 6A and two starboard-side air release units 6B are located on either side of the centerline CL, wherein their plane of symmetry SP is aligned with the centerline CL.

[0072] Figure 12A With Figure 5 The corresponding lower view shows a portion of the boat 200 with an optional configuration of the air release unit 206. The air release unit 206 is... Figure 5 The types disclosed herein are as described, but it should be understood that any variation of the air release unit may be used. They have sidewalls 218A, 218B, which radiate from their plane of symmetry SP at a constant angle of 5 degrees in the rear half of the cavity 233.

[0073] In this configuration, the plane of symmetry SP of the two port-side air release units 206A is inclined outward at a 5-degree angle from the centerline CL of the vessel 200 in the aft direction. In this way, the inner sidewall 218A is aligned substantially parallel to the centerline CL of the vessel, at least in the continuously diverging aft portion. This advantageously ensures that the inner joint 229A is at a constant height on the raised bottom plate. If a scarf-shaped portion (not shown) is used, it can have a constant width and angle. The rear end 221 of the cavity 233 is also inclined outward and has a microbubble blanket 14 distributed thereon, which rises along the raised bottom plate 203 of the vessel 200.

[0074] Figure 12B With Figure 12A The corresponding lower view shows a portion of the vessel 300 with an alternative configuration of the port side air release unit 306. In this case, the air release unit 306 is asymmetrical in shape.

[0075] In fact, in this configuration, the two port-side air release units 306A and the two starboard-side air release units 306B each form a... Figure 4Half of one of the air release units 6 shown is cut along the plane of symmetry SP, which is then aligned with the centerline CL of the vessel 300. This ensures that the inner sidewall 318A is substantially parallel to the vessel's centerline CL, again ensuring that the inner joint 329A is at a constant height on the raised bottom plate. If a scarf-shaped portion (not shown) is used, it can have a constant width and angle. The rear end 321 of the cavity 233 extends laterally in the beam direction and distributes a microbubble blanket 14 that rises along the raised bottom plate 303 of the vessel 300.

[0076] Therefore, this application has been described with reference to certain embodiments described above. It will be appreciated that these embodiments are susceptible to various modifications and substitutions well known to those skilled in the art.

[0077] Many further modifications beyond those described herein can be made to the configurations and techniques described herein without departing from the spirit and scope of this application. Therefore, although specific embodiments have been described, these embodiments are merely examples and not intended to limit the scope of this application.

Claims

1. An air release unit for installation in a hull and mounted to one side of the keel of a vessel having a raised bottom plate, the air release unit comprising a cavity defined by a top wall, a rear wall, and a pair of side walls extending from a nose portion to a rear end portion of the cavity. Its features are, The inner sidewall extends downward to engage the hull at an inner joint, and the outer sidewall extends downward to engage the hull at an outer joint, with the inner joint being lower than the outer joint. The air release unit also includes a deflector plate that spans the cavity between the inner and outer sidewalls, and the deflector plate is angled relative to the line that engages the inner and outer joints in the beam direction.

2. The air release unit according to claim 1, characterized in that, The deflection plate extends horizontally in the direction of the beam.

3. The air release unit according to claim 1, characterized in that, The deflection plate extends horizontally along the keel direction.

4. The air release unit according to claim 1, characterized in that, The top wall extends horizontally in the beam direction and / or keel direction.

5. The air release unit according to claim 1, characterized in that, The sidewall is vertical, at least above the deflection plate.

6. The air release unit according to claim 1, characterized in that, The inner sidewall has a scarf-shaped portion that extends from the adjacent wave deflector to the inner joint.

7. The air release unit according to claim 6, characterized in that, The width of the scarf-like portion is less than 300 mm.

8. The air release unit according to claim 6, characterized in that, The scarf-shaped portion is inclined at 10° to 70° relative to the raised portion of the bottom plate of the hull.

9. The air release unit according to claim 1, characterized in that, It also includes a base plate surrounding the cavity for integration with the hull and arranged to have an inclined portion corresponding to the raised bottom plate of the hull.

10. The air release unit according to claim 1, characterized in that, The horizontal cross-section through the cavity at the location of the deflection plate has a centerline passing through the nose, and the sidewalls are symmetrical about the centerline.

11. The air release unit according to claim 1, characterized in that, The horizontal cross-section through the cavity at the location of the deflection plate has a center line passing through the nose and the center line being parallel to the keel.

12. The air release unit according to claim 1, characterized in that, The sidewalls are symmetrical about a plane of symmetry passing through the nose, and the plane of symmetry is arranged perpendicular to the raised bottom plate.

13. The air release unit according to claim 1, characterized in that, The rear wall of the cavity at the rear of the deflection plate is adjacent to the transition plate, which transitions to be aligned with the hull.

14. The air release unit according to claim 13, characterized in that, The transition plate joins the hull at a line that extends diagonally rearward from the outer joint to the inner joint.

15. The air release unit according to claim 1, characterized in that, The cavity has a maximum length Lc from the nose to the rear end, and the maximum length Lc is between 1m and 10m.

16. The air release unit according to claim 1, characterized in that, The maximum width Wc of the cavity in the horizontal projection is between 50cm and 180cm.

17. The air release unit according to claim 1, characterized in that, The cavity has a maximum height Hc, which is measured as a vertical projection between the lowest point of the deflection plate and the highest point of the top wall, and is between 10cm and 150cm.

18. The air release unit according to claim 1, characterized in that, The cavity has a ratio Lc / Hc in the range of 6:1 to 15:1, a ratio Wr / Hc in the range of 1.3:1 to 5:1, and / or a ratio Lc / Wr in the range of 3.5:1 to 7:

1.

19. The air release unit according to claim 1, characterized in that, The minimum distance between the deflector plate and the outer side of the hull is between 1 mm and 50 mm.

20. The air release unit according to claim 1, characterized in that, The deflection plate is separated from the sidewall by an air gap, which is between 10 mm and 50 mm.

21. The air release unit according to claim 1, characterized in that, The deflection plate includes an opening or multiple small pieces.

22. The air release unit according to claim 1 further includes an air inlet that is in closed communication with the cavity.

23. The air release unit according to claim 1, characterized in that, The air release unit is configured to raise the bottom plate from 2 degrees to 8 degrees.

24. A ship having a hull with a keel, characterized in that, The hull is raised on either side of the keel, and the vessel further includes a plurality of air release units according to any one of the preceding claims, the air release units being mounted in the hull on the port and starboard sides of the keel.

25. The ship according to claim 24, characterized in that, The air release unit is installed in the hull at a position where the hull is raised at an angle of 2 to 8 degrees.

26. The ship according to claim 24, characterized in that, At least a first air release unit and a second air release unit are installed on each side of the keel, with the first air release unit positioned in front and inside relative to the second air release unit.

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