Marine elliptical arc-shaped duct fin

Abstract

This utility model relates to the field of ship design and manufacturing technology, specifically disclosing a marine elliptical arc-shaped ducted fin. The ducted fin extends along the axis of the propeller and includes an icebreaking duct and several pre-rotating fins. The marine elliptical arc-shaped ducted fin has opposing icebreaking and near-propeller sides along the propeller axis, with the icebreaking side facing the bow of the hull and the propeller positioned closer to the near-propeller side relative to the icebreaking side. The icebreaking duct has several evenly distributed serrated grooves on its icebreaking side. The edge of the icebreaking duct has an arc surface, with tangential transition slopes on both sides of the arc surface. The distance between the two transition slopes gradually increases from the icebreaking side to the near-propeller side; and the icebreaking side gradually approaches the near-propeller side from the hull to the icebreaking duct. This ducted fin improves navigation safety in ice-covered areas, maximizes energy savings, and achieves improved design and energy-saving optimization of the flow field at the stern of the hull in ice-covered conditions.

Description

Technical Field

[0001] This utility model relates to the field of ship design and manufacturing technology, and in particular to marine elliptical arc-shaped duct fins. Background Technology

[0002] Currently, developing efficient hydrodynamic energy-saving technologies for ships is a key measure for energy conservation and emission reduction. With the continuous development of the shipbuilding industry, hydrodynamic energy-saving technologies for ships operating in conventional navigation areas are facing new challenges and opportunities.

[0003] For vessels operating in conventional navigation areas, hydrodynamic energy-saving technologies primarily revolve around the hydrodynamic configuration of energy-saving devices, aiming to achieve superior energy efficiency. This is especially true for newer generations of vessels with superior speed and stern profiles, which feature slimmer stern lines and more uniform stern flow, placing higher demands on the design of energy-saving devices. To further explore energy-saving potential, the market has seen the emergence of numerous innovative energy-saving devices with unique configurations, as well as complex, combined energy-saving devices based on traditional configurations.

[0004] However, ship energy-saving technology design has some specific requirements. While ensuring energy-saving effects, some energy-saving devices cannot pose structural safety risks. Therefore, the existing design concept of fin-extended ducts and most high-efficiency hydrodynamic energy-saving devices on the market are not suitable for all energy-saving scenarios with special requirements. Utility Model Content

[0005] The purpose of this invention is to provide a marine elliptical arc-shaped duct fin to solve the problems of energy saving and navigation safety for ships in ice-covered areas.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] A marine elliptical arc-shaped ducted fin is mounted on the hull, on which a propeller is rotatably connected. The elliptical arc-shaped ducted fin extends along the axis of the propeller and includes an icebreaking duct and several pre-rotating fins. The elliptical arc-shaped ducted fin has opposing icebreaking and near-propeller sides along the axis of the propeller. The icebreaking side faces the bow of the hull, and the propeller is positioned closer to the near-propeller side relative to the icebreaking side. The icebreaking duct has several evenly distributed serrated grooves on its icebreaking side. The edge of the icebreaking duct on its icebreaking side has an arc surface, and both sides of the arc surface have tangential transition slopes. The distance between the two transition slopes gradually increases along the direction from the icebreaking side to the near-propeller side. Along the direction from the hull to the icebreaking duct, the icebreaking side gradually approaches the near-propeller side.

[0008] As an optional technical solution for marine elliptical arc-shaped duct fins, a rectangular coordinate system is defined in a plane perpendicular to the axis of the propeller, with the projection point of the propeller axis as the origin. The positive Y-axis of the rectangular coordinate system is perpendicular to the horizontal plane and points upward. The projection of the icebreaking duct is a minor arc of an ellipse with its center located at the origin. The minor axis of the projection of the icebreaking duct coincides with the Y-axis. The pre-rotating fin radiates outward from the origin and connects the icebreaking duct and the hull.

[0009] As an optional technical solution for marine elliptical arc-shaped duct fins, the pre-rotating fin includes a first pre-rotating fin and a second pre-rotating fin. The first pre-rotating fin and the second pre-rotating fin are respectively connected to the two ends of the icebreaking duct. The angle between the projection of the first pre-rotating fin and the positive Y-axis is 45°-120°, and the angle between the projection of the second pre-rotating fin and the positive Y-axis is 5°-60°. The projections of the first pre-rotating fin and the second pre-rotating fin are located on opposite sides of the Y-axis.

[0010] As an optional technical solution for marine elliptical arc-shaped duct fins, the radius of the propeller is R, the major axis of the projection of the icebreaking duct is a, the minor axis is b, and the equation of the projection of the icebreaking duct is x. 2 / a 2 +y 2 / b 2 =1; where 1.00R>a>0.60R, 0.75R>b>0.50R, a>b.

[0011] As an optional technical solution for marine elliptical arc-shaped duct fins, the projected length of the first pre-rotating fin is 0.60R-1.00R, and the projected length of the second pre-rotating fin is 0.50R-0.75R.

[0012] As an optional technical solution for marine elliptical arc-shaped ducted fins, the cross-section of the pre-rotating fin is an airfoil profile.

[0013] As an optional technical solution for marine elliptical arc-shaped duct fins, the projection of the pre-rotating fin in a plane perpendicular to its direction of movement is a right trapezoid, and the sweep angle θ of the projection of the pre-rotating fin is 0°-10°.

[0014] As an optional technical solution for marine elliptical arc-shaped ducting fins, the marine elliptical arc-shaped ducting fins translate or rotate in a plane perpendicular to the axis of the propeller.

[0015] As an optional technical solution for marine elliptical arc-shaped duct fins, the projection of the second pre-rotating fin is located in the first quadrant of the rectangular coordinate system; at least two more pre-rotating fins are also provided between the first pre-rotating fin and the second pre-rotating fin, and their projections are located in the first or second quadrant of the rectangular coordinate system.

[0016] As an optional technical solution for marine elliptical arc-shaped ducted fins, when the propeller rotates to the right, the positive X-axis of the rectangular coordinate system is located to the right of the Y-axis when viewed from the icebreaking side to the near-propeller side; when the propeller rotates to the left, the positive X-axis of the rectangular coordinate system is located to the left of the Y-axis when viewed from the icebreaking side to the near-propeller side.

[0017] The beneficial effects of this utility model are:

[0018] The ship's elliptical arc-shaped ducting fins feature a differentiated design for the icebreaking and propeller-proximal sides. The icebreaking side prioritizes handling ice collisions, guiding ice outwards, while the propeller-proximal side focuses on flow field control. The bow-facing design of the icebreaking side creates an active icebreaking zone at the leading edge of the duct. Its axial extension helps balance flow guidance with structural weight, forming an axial acceleration channel for propeller inlet. The pressure gradient design from the icebreaking side to the propeller-proximal side effectively suppresses energy loss in the circumferential flow. The serrated grooves create a discontinuous collision interface, generating stress concentration points during ice collisions that promote ice breakage, dispersing ice impact loads and reducing the overall peak stress on the icebreaking duct. The gaps between the serrations form flow channels, accelerating the sliding of ice fragments towards the outside of the duct and reducing the likelihood of large ice floes entering the propeller region. The spaced distribution of the serrations breaks the flow separation trend at the leading edge of the duct, improving boundary layer adhesion characteristics through controllable micro-vortices. The combined design of the arc surface and the transition slope forms a "ski"-like guide surface with a continuous curvature transition. This reduces the contact area during ice floe collisions, lowers frictional resistance, and allows the colliding ice floes to slide outwards along the transition slope under centrifugal force, promoting the removal of ice fragments from the propeller area. The gradually increasing distance between the two slopes matches the size distribution of the broken ice. Furthermore, the slope transition design avoids sharp-angle stress concentration, improving the impact fatigue resistance of the icebreaking duct's leading edge. Simultaneously, the arc surface creates a local streamlined contraction acceleration zone, and the diffusion angle design of the transition slope controls flow separation; both work together to achieve efficient utilization of boundary layer energy. The gradually tapering layout from the icebreaking side to the propeller side forms a streamlined guide surface, reducing the obstruction effect of the icebreaking duct on the incoming flow and allowing the angle of attack at the icebreaking duct inlet to automatically match changes in the incoming flow velocity direction. The inclined structure forms a natural ice-discharge channel outwards, shortening the path of the ice floes. Combined with the propeller's suction action, this promotes the discharge of ice fragments along a predetermined path from the area in front of the propeller's hydrodynamic energy-saving device, further enhancing the safety of the vessel navigating in ice-covered areas. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the marine elliptical arc-shaped duct fin provided in this embodiment of the utility model;

[0020] Figure 2 This is an unfolded view of the ice-breaking catheter provided in this embodiment of the utility model;

[0021] Figure 3 yes Figure 2 Cross-sectional view of the C-plane;

[0022] Figure 4 This is a front view of the first pre-spinning fin provided in this embodiment of the utility model;

[0023] Figure 5 This is a cross-sectional view of the first pre-rotating fin provided in an embodiment of the present invention.

[0024] In the picture:

[0025] 100. Ice-breaking type conduit; 101. Transition slope; 102. Circular arc surface; 103. Serrated groove;

[0026] 210. First pre-rotating fin; 220. Third pre-rotating fin; 230. Fourth pre-rotating fin; 240. Second pre-rotating fin;

[0027] 900, hull. Detailed Implementation

[0028] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0029] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The terms "first position" and "second position" refer to two different positions. Moreover, "above," "on top of," and "over" the first feature in relation to the second feature includes the first feature directly above and diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "under," and "below" the first feature in relation to the second feature includes the first feature directly below and diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0030] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0031] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0032] like Figures 1 to 5 As shown, this embodiment provides a marine elliptical arc-shaped duct fin, which is mounted on the hull 900. A propeller is rotatably connected to the hull 900. The marine elliptical arc-shaped duct fin extends along the axis of the propeller and includes an icebreaking duct 100 and several pre-rotating fins. The marine elliptical arc-shaped duct fin has an icebreaking side and a near-propeller side along the axis of the propeller. The icebreaking side faces the bow of the hull 900, and the propeller is positioned closer to the near-propeller side relative to the icebreaking side. The icebreaking duct 100 has several serrated grooves 103 evenly distributed on the icebreaking side. The icebreaking duct 100 has an arc surface 102 at the edge of the icebreaking side. The arc surface 102 has tangential transition slopes 101 on both sides. The distance between the two transition slopes 101 gradually increases along the direction from the icebreaking side to the near-propeller side. Along the direction from the hull 900 to the icebreaking duct 100, the icebreaking side gradually approaches the near-propeller side.

[0033] The ship's elliptical arc-shaped duct fins feature a differentiated design for the icebreaking and propeller-proximal sides. The icebreaking side prioritizes handling ice collisions, guiding the ice outwards, while the propeller-proximal side focuses more on flow field control. The bow-facing design of the icebreaking side creates an active icebreaking zone at the leading edge of the icebreaking duct 100. Its axial extension helps balance the guiding effect with structural weight, and the axial extension forms an axial acceleration channel for the propeller inlet. The pressure gradient design from the icebreaking side to the propeller-proximal side effectively suppresses energy loss in the circumferential flow. The serrated grooves 103 create a discontinuous collision interface, generating stress concentration points during ice collisions that promote ice breakage, dispersing the impact load of the ice layer and reducing the overall peak stress of the icebreaking duct 100. The gaps between the serrations form a guiding channel, accelerating the sliding of broken ice towards the outside of the icebreaking duct 100 and reducing the likelihood of large ice floes entering the propeller region. The spaced distribution of the serrated grooves 103 breaks the flow separation trend at the leading edge of the icebreaking duct 100, improving boundary layer adhesion characteristics through controllable micro-vortices. The combined design of the arc surface 102 and the transition slope 101 forms a "ski"-like guide surface with a continuous curvature transition. This reduces the contact area during ice floe collisions, lowers frictional resistance during collisions, and allows the colliding ice floes to slide outwards along the transition slope 101 under centrifugal force, promoting the escape of ice fragments from the propeller area. The gradually increasing distance between the two slopes matches the size distribution of the broken ice. Furthermore, the slope transition design avoids sharp-angle stress concentration, improving the impact fatigue resistance of the leading edge of the icebreaking duct 100. Simultaneously, the arc surface 102 forms a local streamlined contraction acceleration zone, and the diffusion angle design of the transition slope 101 controls flow separation; the two work together to achieve efficient utilization of boundary layer energy. The gradually tapering layout from the icebreaking side to the near-propeller side forms a streamlined guide surface, reducing the obstruction effect of the icebreaking duct 100 on the incoming flow and allowing the angle of attack at the inlet of the icebreaking duct 100 to automatically match changes in the direction of the incoming flow velocity. The inclined structure forms a natural ice-discharge channel to the outside of the hull, shortening the path of floating ice. Combined with the suction effect of the propeller, it causes the broken ice to be discharged along a predetermined path from the area in front of the propeller hydrodynamic energy-saving device, which is more conducive to the safety of the hull 900 when navigating in ice areas.

[0034] In this embodiment, a rectangular coordinate system is defined in a plane perpendicular to the axis of the propeller, with the projection point of the propeller axis as the origin. The positive Y-axis of the rectangular coordinate system is perpendicular to the horizontal plane and points upward. The projection of the icebreaking duct 100 is an elliptical minor arc with the center located at the origin. The minor axis of the projection of the icebreaking duct 100 coincides with the Y-axis. The pre-rotating fin radiates outward from the origin and connects the icebreaking duct 100 and the hull 900.

[0035] The icebreaking duct 100 is designed with a minor elliptical arc projection and its minor axis coinciding with the Y-axis. This design maximizes the distance from the top of the icebreaking duct 100 to the lowest ice line, significantly reducing the probability of collision between the icebreaking duct 100 and the ice layer, and optimizing the layout of the marine elliptical arc duct fin. This design helps to expand the icebreaking range of the icebreaking duct 100, reduce the risk of ice floes colliding with the propeller, and improve the safety of the hull 900 in ice-covered areas. The radial distribution of the icebreaking duct 100 and the pre-spinning fins works synergistically to precisely match the axial and circumferential flow characteristics of the wake field at the stern, enhancing the connection strength between the icebreaking duct 100 and the hull 900. The two ends of the pre-spinning fins connect to the icebreaking duct 100 and the hull 900 respectively, forming a stable support structure. The minor axis of the icebreaking duct 100 projection is aligned with the vertical load direction of the hull 900, reducing the risk of stress concentration during ice collisions and contributing to enhanced structural safety.

[0036] Specifically, the arrangement of the icebreaking duct 100 is determined based on the flow conditions at the stern of the hull 900 and the position of the ice line of the hull 900 in the ice zone.

[0037] Furthermore, the pre-rotating fin includes a first pre-rotating fin 210 and a second pre-rotating fin 240. The first pre-rotating fin 210 and the second pre-rotating fin 240 are respectively connected to the two ends of the ice-breaking conduit 100. The angle between the projection of the first pre-rotating fin 210 and the positive Y-axis is 45°-120°, and the angle between the projection of the second pre-rotating fin 240 and the positive Y-axis is 5°-60°. The projections of the first pre-rotating fin 210 and the second pre-rotating fin 240 are located on both sides of the Y-axis.

[0038] The first pre-spinning fin 210 and the second pre-spinning fin 240 are positioned on either side of the Y-axis, precisely covering the unfavorable pre-spinning flow field regions on the propeller disk. This allows for precise control of the circumferential flow, improving the uniformity of the flow field on the propeller disk by accelerating the flow in the low-speed region. It also prevents the pre-spinning fins from extending beyond the ice-breaking duct 100 and avoids the pre-spinning fins from concentrating in the same area, reducing the risk of ice buildup. The first pre-spinning fin 210 covers the strong pre-spinning region in the second or third quadrant, while the second pre-spinning fin 240 targets the flow separation region in the first quadrant. By weakening unfavorable pre-spinning flow, it improves propeller propulsion efficiency and optimizes energy saving.

[0039] In this embodiment, the radius of the propeller is R, the major axis of the projection of the ice-breaking duct 100 is a, the minor axis is b, and the equation of the projection of the ice-breaking duct 100 is x. 2 / a 2 +y 2 / b 2 =1; where 1.00R>a>0.60R, 0.75R>b>0.50R, a>b.

[0040] By defining the ratio between the minor axis of the ellipse and the radius R of the propeller, a safe distance is maintained between the uppermost point of the icebreaking duct 100 and the ice line. By defining the ratio between the major axis of the ellipse and the radius R of the propeller, the shape of the icebreaking duct 100 is adapted to the spatial distribution of unfavorable flow regions on the stern propeller disk of different ship types, optimizing the local flow field acceleration effect. This parametric design of the elliptical equation allows for rapid adjustment of the dimensions of the icebreaking duct 100 to suit the stern flow characteristics of different ship types, achieving parameter matching optimization. The parameter range of the elliptical equation covers the propeller radius variation requirements of mainstream ship types, ensuring that the major axis matches the lateral distribution of the low-speed region of the wake flow at the stern, maximizing the acceleration effect of the icebreaking duct 100 in the low-speed region. Simultaneously, the constraint a>b ensures that the icebreaking duct 100 has sufficient structural stiffness in the circumferential flow direction, avoiding insufficient structural strength due to an excessively long major axis. The ice-breaking duct 100, which unfolds into a flat plate shape, achieves the flow guiding effect of an equivalent airfoil-shaped ice-breaking duct 100 through parameter control, making it easier to meet the structural strength requirements of ice-covered areas. Moreover, by increasing the thickness of the flat plate, the structural strength of the ice-breaking duct 100 is ensured.

[0041] Furthermore, the projected length of the first pre-rotating fin 210 is 0.60R-1.00R, and the projected length of the second pre-rotating fin 240 is 0.50R-0.75R.

[0042] The length range of the first pre-spinning fin 210 is limited to cover the high-energy flow region outside the boundary layer of the hull 900, while the length range of the second pre-spinning fin 240 is limited to precisely act on the strong pre-spinning region at the propeller disk inlet. Together, they achieve full-range flow control from the hull 900 to the propeller disk, keeping the pre-spinning fin length within a reasonable range and avoiding stress concentration during ice collisions due to excessive length, thus further improving structural safety. Simultaneously, the pre-spinning fin length adapts to the wake space distribution at the stern, ensuring that the pre-spinning fins effectively connect the icebreaking duct 100 to the hull 900, covering critical areas with pre-spinning action. Furthermore, the pre-spinning fin length matches the size ratio of the icebreaking duct 100, dispersing impact energy through elastic deformation during ice collisions, preventing structural stress concentration due to excessive length, reducing the risk of pre-spinning fin damage, and ensuring adaptability within the length range. Based on the synergistic cooperation between the length parameters and the endpoint position of the icebreaking duct 100, unfavorable flow regions on the propeller disk are precisely covered, ensuring accurate flow field control.

[0043] For example, the cross-section of the pre-rotating fin is an airfoil section.

[0044] Specifically, the arrangement of the airfoil profile is determined based on the flow conditions at the stern of the hull (900) and the position of the ice line at the hull (900) in ice-covered areas; the angle of attack of the airfoil profile varies along the length of the pre-rotating fin and is determined based on the size and intensity distribution of the unfavorable flow region at the stern, in order to adapt to the spatial distribution of the wake at the stern. The method of variation and the selection of specific values ​​are conventional technical means in this field and are well-versed by those skilled in the art, and will not be elaborated upon here.

[0045] The airfoil profile design optimizes hydrodynamic performance, reduces flow separation, lowers the additional drag of the pre-spinning fin, and enhances the pre-spinning effect. This allows the pre-spinning fin to achieve maximum flow guidance capacity with minimal thickness. The leading-edge radius is optimized to match the local incoming flow angle of attack, and the straight trailing-edge section reduces the risk of flow separation, preventing the energy-saving effect from being negated by flow field interference, thus optimizing flow field drag. The structure where the profile chord length varies along the length of the pre-spinning fin achieves a gradient distribution of strength, resulting in a reasonable airfoil profile thickness distribution and higher bending resistance under icy collision conditions. The streamlined shape of the airfoil's leading edge reduces the contact area during ice collisions, and the straight trailing-edge design prevents ice fragments from getting stuck, overall reducing the instantaneous impact intensity of ice loads and contributing to optimized dynamic response to ice collisions.

[0046] Furthermore, the projection of the pre-spinning fin onto a plane perpendicular to its direction of movement is a right trapezoid, and the sweep angle θ of the projection of the pre-spinning fin is 0°-10°.

[0047] The sweep angle θ matches the radial velocity gradient of the wake at the stern, ensuring that all sections of the pre-spinning fin are always at the optimal angle of attack. The right-angled trapezoidal projection creates a continuous distribution of spanwise loads, enabling chord length gradient variations, suppressing energy loss due to flow separation, and increasing the time gradient of ice collision contact. Simultaneously, the swept-back right-angled trapezoidal layout keeps the pre-spinning fin tip 90° away from the hull, reducing additional drag from the wetted surface area, achieving dynamic attenuation of ice loads, lowering the risk of ice debris accumulation, and realizing adaptive wake field design.

[0048] In this embodiment, the marine elliptical arc-shaped duct fin translates or rotates in a plane perpendicular to the axis of the propeller.

[0049] The above-mentioned limitations define the movement of the marine elliptical arc-shaped duct fin, ensuring its long-term stable operation according to design requirements.

[0050] In one embodiment of this invention, the pre-spinning fins are in a plane perpendicular to the axis of the propeller; all the pre-spinning fins are evenly distributed around the axis of the propeller.

[0051] The uniform distribution method allows the water flow to pre-swirl evenly around the propeller, providing stable propulsion and making it suitable for conventional navigation conditions.

[0052] In another embodiment of this invention, the pre-rotating fins are in a plane perpendicular to the axis of the propeller; all the pre-rotating fins are spaced apart.

[0053] Interval arrangement allows for flexible adjustment of the pre-swirl degree and distribution of the water flow according to the specific operating conditions and water flow characteristics of the ship, enhancing the ship's adaptability and maneuverability to meet the needs of different navigation conditions.

[0054] The aforementioned flexible pre-rotating fin layout can be selected according to the design requirements of different vessels, the navigation environment, and the characteristics of the propeller, in order to achieve the best water flow pre-rotation effect and propulsion performance.

[0055] In this embodiment, the projection of the second pre-spinning fin 240 is located in the first quadrant of the rectangular coordinate system; at least two pre-spinning fins are also provided between the first pre-spinning fin 210 and the second pre-spinning fin 240, and their projections are located in the first or second quadrant of the rectangular coordinate system.

[0056] The addition of intermediate pre-spinning fins in the first and second quadrants fills the flow control gaps in these quadrants, creating a multi-level, layered control of the tail flow field. This is used to correct the lateral secondary flow in the gap area between the hull 900 and the icebreaking duct 100, further weakening the intensity of unfavorable circumferential pre-spinning flow and achieving multi-level flow field control. The circumferential distribution of multiple fins forms a "stepped" pre-spinning correction, progressively weakening unfavorable flows at different radii and achieving multi-dimensional flow correction. Simultaneously, the distribution of intermediate pre-spinning fins in the first and second quadrants creates inclined guide surfaces, prompting floating ice to slide outwards along the pre-spinning fin gaps towards the hull 900, controlling the sliding path and reducing the probability of ice fragments accumulating at the root of the icebreaking duct 100. Moreover, the distributed layout of all pre-spinning fins helps reduce the risk of localized ice fragment accumulation, enhances the overall structural rigidity of the icebreaking duct 100, reduces vibration risks during navigation in ice-covered areas, achieves synergistic structural reinforcement, and improves safety during navigation in ice-covered areas. Moreover, the partitioned arrangement of the second pre-rotating fin 240 and the intermediate pre-rotating fin can make targeted pre-rotating adjustments to the water flow in different areas around the propeller, better adapt to the working characteristics of the propeller, improve propulsion efficiency, and also help balance the forces on the ship during navigation.

[0057] Specifically, the airfoil shape, size, installation position, and angle of the pre-rotating fin are determined by those skilled in the art based on the actual engineering situation. The specific determination method is a conventional technical means in the art, which will not be elaborated here.

[0058] Furthermore, when the propeller rotates clockwise, viewed from the icebreaking side to the side closest to the propeller, the positive X-axis of the Cartesian coordinate system is located to the right of the Y-axis; when the propeller rotates counterclockwise, viewed from the icebreaking side to the side closest to the propeller, the positive X-axis of the Cartesian coordinate system is located to the left of the Y-axis.

[0059] Based on the propeller's rotation direction, the position of the positive X-axis relative to the Y-axis in a Cartesian coordinate system is determined. This design allows the pre-rotation direction of the pre-rotating fins to match the propeller's rotation direction, ensuring that the water enters in a manner most suitable for the propeller's rotation direction. This improves the propeller's propulsion efficiency and the ship's overall performance, reduces energy loss caused by the mismatch between the water flow and the propeller's rotation direction, and thus fully utilizes the propeller's performance.

[0060] In this embodiment, the propeller rotation direction is taken as a right-handed propeller. For left-handed propellers, this embodiment requires a left-right mirror adjustment of the above settings. The specific mirror adjustment method is common knowledge in the art and is well known to those skilled in the art, so it will not be described in detail here.

[0061] To match specific ice zone requirements, the major and minor axes of the ice-breaking duct 100 and the sweep angle θ of the pre-spinning fin can be adjusted according to different wake field conditions and ice zone safety requirements. The above settings help to maximize energy-saving effects while ensuring ice zone safety.

[0062] This embodiment uses the following type of ship as an example for illustration.

[0063] The main dimensions and technical specifications of the target ship are as follows: overall length is 244.30m, beam is 44.00m, design draft is 13.50m, displacement is 114000.00t, speed is 14.50kn, propeller rotates clockwise around its own axis, propeller diameter is 8.40m, and propeller design speed is 72.00r / min.

[0064] Then, the longitudinal distance from the near-propeller side of the marine elliptical arc-shaped duct fin to the propeller disk surface was determined to be 1.35m. The focus of the icebreaking duct 100 is located on the X-axis, and the equation of the projected ellipse is x. 2 / (0.90R) 2 +y 2 / (0.70R) 2 =1. On the minor axis of the elliptical projection, the uppermost point of the marine elliptical arc-shaped duct fin is more than 1 meter away from the lowest ice line, making the possibility of the icebreaking duct 100 colliding with the ice low.

[0065] The positions of the starting point A and the ending point B of the icebreaking duct 100 are determined according to the location and size of the unfavorable flow area on the propeller disk. The starting point A is located on the port side, and the angle between the line segment AO connecting point A and the origin O and the positive direction of the Y-axis is 90°, with a length of 0.90R. The ending point B is located on the starboard side, and the angle between the line segment BO connecting point B and the origin O and the positive direction of the Y-axis is 20°. The icebreaking duct 100 spans the first and second quadrants.

[0066] The icebreaking duct 100 is a flat plate with an acute-angled guide circle design on its leading edge near the bow. This reduces the contact area during ice floe collisions, allowing the impacting ice to slide away from the icebreaking duct 100 and avoid being directly engulfed by the propeller area. The circumferential distribution of the leading edge of the icebreaking duct 100 near the bow is serrated, which aids in the separation of ice fragments after an ice floe collision.

[0067] Based on the principle of maximizing pre-spin, the icebreaking duct 100 and the hull 900 are connected by four pre-spinning fins: a first pre-spinning fin 210, a second pre-spinning fin 240, a third pre-spinning fin 220, and a fourth pre-spinning fin 230. The pre-spinning fins are radially distributed outwards from the propeller axis. The end of the first pre-spinning fin 210 furthest from the origin O is connected to the starting point A of the icebreaking duct 100. The end of the second pre-spinning fin 240 furthest from the origin O is connected to the ending point B of the icebreaking duct 100. The third pre-spinning fin 220 and the fourth pre-spinning fin 230 are located between the first and second pre-spinning fins 210 and 240. The third pre-spinning fin 220 is located in the second quadrant, with the line connecting its two ends forming a 30° angle with the positive Y-axis. The fourth pre-spinning fin 230 is located in the second quadrant, with the line connecting its two ends forming a 60° angle with the positive Y-axis. All of the above pre-spinning fins do not extend beyond the elliptical icebreaking duct 100. The cross-section of the pre-spinning fin varies along the span direction and is arranged into a swept-back right-angled trapezoid with a sweep angle θ of 5°.

[0068] The energy-saving device design meets the requirements for navigation in ice-covered areas, is structurally safe, and has a significant energy-saving effect, reducing ship fuel consumption by 4%-8%.

[0069] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. An elliptical arc ducted propeller for a ship, provided on a ship body (900), a propeller being rotatably connected to the ship body (900), characterized in that, The marine elliptical arc-shaped duct fin extends along the axis of the propeller and includes an icebreaking duct (100) and several pre-rotating fins. The marine elliptical arc-shaped duct fin has an icebreaking side and a near-propeller side along the axis of the propeller, with the icebreaking side facing the bow of the hull (900), and the propeller being positioned close to the near-propeller side relative to the icebreaking side. The ice-breaking conduit (100) has several serrated grooves (103) evenly distributed on the ice-breaking side. The ice-breaking duct (100) has an arc surface (102) on the edge of the ice-breaking side, and transition slopes (101) tangent to the arc surface (102) are provided on both sides of the arc surface (102). The distance between the two transition slopes (101) gradually increases along the direction from the ice-breaking side to the near-paddle side. Along the direction from the hull (900) to the icebreaking duct (100), the icebreaking side gradually approaches the near-paddle side.

2. The elliptical arc ducted hydrofoil according to claim 1, characterized in that, In a plane perpendicular to the axis of the propeller, a rectangular coordinate system is defined with the projection point of the axis of the propeller as the origin. The positive Y-axis of the rectangular coordinate system is perpendicular to the horizontal plane and upward. The projection of the icebreaking duct (100) is an elliptical minor arc with the center located at the origin. The minor axis of the projection of the icebreaking duct (100) coincides with the Y-axis. The pre-rotating fin radiates outward from the origin and connects the icebreaking duct (100) and the hull (900).

3. The elliptical arc ducted hydrofoil according to claim 2, characterized in that, The pre-rotating fin includes a first pre-rotating fin (210) and a second pre-rotating fin (240). The first pre-rotating fin (210) and the second pre-rotating fin (240) are respectively connected to the two ends of the ice-breaking conduit (100). The angle between the projection of the first pre-rotating fin (210) and the positive Y-axis is 45°-120°, and the angle between the projection of the second pre-rotating fin (240) and the positive Y-axis is 5°-60°. The projections of the first pre-rotating fin (210) and the second pre-rotating fin (240) are located on both sides of the Y-axis.

4. The elliptical arc ducted hydrofoil according to claim 3, characterized in that, The radius of the propeller is R, the major axis of the projection of the ice-breaking duct (100) is a, the minor axis is b, and the equation of the projection of the ice-breaking duct (100) is x. 2 / a 2 +y 2 / b 2 =1; where 1.00R>a>0.60R, 0.75R>b>0.50R, a>b.

5. The elliptical arc ducted hydrofoil according to claim 4, characterized in that, The projected length of the first pre-rotating fin (210) is 0.60R-1.00R, and the projected length of the second pre-rotating fin (240) is 0.50R-0.75R.

6. The marine oval arc ducted fin according to claim 1, characterized in that, The cross-section of the pre-rotating fin is an airfoil section.

7. The marine oval arc ducted fin according to claim 6, characterized in that, The projection of the pre-rotating fin in a plane perpendicular to its direction of movement is a right trapezoid, and the sweep angle θ of the projection of the pre-rotating fin is 0°-10°.

8. The marine oval arc ducted fin according to claim 1, characterized in that, The marine elliptical arc-shaped duct fin translates or rotates in a plane perpendicular to the axis of the propeller.

9. The marine oval arc ducted fin according to claim 3, characterized in that, The projection of the second pre-rotating fin (240) is located in the first quadrant of the rectangular coordinate system; at least two more pre-rotating fins are provided between the first pre-rotating fin (210) and the second pre-rotating fin (240), and their projections are located in the first or second quadrant of the rectangular coordinate system.

10. The marine oval arc ducted fin according to claim 9, characterized in that, When the propeller rotates clockwise, the positive X-axis of the Cartesian coordinate system is located to the right of the Y-axis when viewed from the icebreaking side to the near-propeller side; when the propeller rotates counterclockwise, the positive X-axis of the Cartesian coordinate system is located to the left of the Y-axis when viewed from the icebreaking side to the near-propeller side.

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