Ship flow control system having pre-swirl flow control fin

Abstract

The present invention relates to a ship flow control system having a pre-swirl flow control fin, wherein a swirl flow is generated opposite to the propeller rotation direction such that the ship propulsion efficiency is improved without increasing cavitation and hull fluctuation pressure occurring in the upper portion of the starboard of the ship. The ship flow control system comprises a flow control fin installed in a curved portion of the stern of the port side of the ship positioned in front of the propeller so as to be inclined toward the lower side with respect to the basic flow direction of seawater, thereby inducing the seawater flow direction to face the lower side of the propeller. By generating a swirl flow in the counterclockwise direction, which is opposite to the propeller rotation direction, such that the ship propulsion efficiency is improved without increasing cavitation and hull fluctuation pressure occurring in the upper portion of the starboard of the ship.

Description

Marine flow control system equipped with a current flow control pin

[0001] The present invention relates to a flow control fin for a ship, and more particularly to a flow control system for a ship that improves the propulsion efficiency of a ship by generating a swirling flow opposite to the direction of propeller rotation, without increasing cavitation and hull fluctuation pressure occurring on the upper starboard side of the ship.

[0002] The primary function of a propeller mounted on a ship is to convert rotational motion into linear motion. Since the propeller blades are attached at an angle to the plane of rotation, they push the water as they rotate, and the ship moves forward as a reaction to this force.

[0003] At this time, the propeller pushes the seawater backward while simultaneously rotating the seawater before and after the propeller, but this rotational flow does not contribute to thrust and becomes energy that is lost.

[0004] In a symmetrical vessel, the flow of seawater originating from the bow passes through the midline parallel of the hull and flows along the bilge at the stern bend, generating a vortex. Generally, since propellers rotate clockwise, the rotational flow caused by the propeller on the starboard side of the hull is offset by the bilge vortex, while on the port side, the bilge vortex accelerates the rotation of the flow caused by the propeller. Consequently, as the vessel moves, seawater flows into the propeller with a tangential velocity rotating in the same direction as the propeller's rotation. This causes the propeller to generate different thrusts on the port and starboard sides, resulting in reduced propulsion efficiency and causing problems such as cavitation and vibration.

[0005] Conventional technologies proposed to address these issues include asymmetric stern vessels, counter-rotating propellers, and current-fixing blades. First, the asymmetric stern vessel fundamentally prevents the development of bilge vortices by altering the shape of the port side of the hull; this increases propulsion efficiency by creating a swirling flow opposite to the propeller's rotation direction at the propeller's leading edge. The counter-rotating propeller (CRP) has the advantage of maximizing the recovery of rotational kinetic energy by operating two propellers rotating in different directions simultaneously. Additionally, current-fixing blades improve propulsion efficiency by controlling the tangential velocity of seawater; multiple blade structures located in front of the propeller change the angle of seawater inflow toward the propeller.

[0006] However, despite their respective advantages, the aforementioned methods had limitations that made them difficult to apply to actual vessels. Specifically, asymmetrical stern vessels required separate designs for the left and right sides, resulting in complex design and manufacturing processes and high costs, which led to few instances of construction. Additionally, counter-rotating propellers were difficult to apply to large vessels due to the highly complex shaft system design process and the significant heat, noise, and vibration they generated. On the other hand, the installation of current-fixing blades remains the most practical method currently in widespread use. However, since current-fixing blades must be mounted directly in front of the propeller, they required large structures to control shear flow that was already sufficiently developed. This resulted in a significant increase in vessel resistance and caused problems such as cavitation and noise.

[0007] Accordingly, the present invention is proposed to resolve the aforementioned conventional problems, and the objective of the present invention is to provide a ship flow control system that improves the propulsion efficiency of a ship by generating a swirling flow opposite to the propeller rotation direction, without increasing cavitation and hull fluctuation pressure occurring on the upper starboard side of the ship.

[0008] To achieve the above-mentioned purpose, a ship flow control system according to the technical concept of the present invention is characterized by its technical configuration by including a flow control fin installed at an angle facing downward relative to the basic flow direction of seawater in the port stern curve of the ship located in front of the propeller, which induces the flow direction of seawater to face downward relative to the propeller, thereby generating a counterclockwise swirling flow opposite to the rotation direction of the propeller, and improving the propulsion efficiency of the ship without increasing cavitation and hull fluctuation pressure occurring on the upper starboard side of the ship.

[0009] Here, the flow control fin is attached to the inner side of the port stern curve of the vessel so as to align with the basic flow direction of the seawater, and is formed in a twisted shape that slopes downward toward the rear as it extends toward the outer end, thereby guiding the flow direction of the seawater toward the lower side of the propeller.

[0010] In addition, the above-mentioned flow control pin may be characterized by being formed in the shape of a rectangular plate, with a shape that gradually twists from the inner side to the outer side.

[0011] In addition, the above-mentioned flow control pin may be characterized in that the inner side, outer side, front side, and rear side are all formed in a straight line shape.

[0012] In addition, the flow control fin may be characterized by comprising an inner plate attached to the port stern curve of the vessel to align with the basic flow direction of seawater, and an outer plate attached to the inner plate so as to be inclined downward toward the rear relative to the inner plate to guide the flow direction of seawater toward the lower side of the propeller.

[0013] In addition, the first outer side of the inner plate and the second inner side of the outer plate may intersect in an X shape, and the space between the first outer side of the inner plate and the second inner side of the outer plate may be filled by joining two triangular plates.

[0014] In addition, the above-mentioned flow control fin may be characterized by being attached such that its inner side aligns with the basic flow direction of seawater at the port stern curve of the vessel, and having a shape that is twisted and bent so as to slope downward toward the rear from the middle section between the inner side and the outer side, thereby guiding the flow direction of seawater toward the lower side of the propeller.

[0015] In addition, the front side of the flow control pin may be formed in a straight shape, and the rear side may be characterized by being bent at a maximum angle to maximize the flow control effect.

[0016] In addition, the above flow control fin may be characterized by being formed to have a length in the range of 1% to 3% of the ship's length and a width in the range of 2% to 10% of the ship's width.

[0017] In addition, the above flow control fin may be characterized by being located within 10% to 25% of the ship's length from the stern waterline towards the bow, and within 50% of the planned draft height from the bottom of the hull.

[0018] In addition, the flow control fin may be characterized by being attached along the basic flow direction of seawater at an angle of within 30 degrees in the deck direction relative to the horizontal plane of the bottom of the ship, and having a twist angle ranging from 10 to 30 degrees as it extends outward along the central axis of the flow control fin.

[0019] In addition, it may further include an auxiliary control pin having the same shape as the above-mentioned flow control pin and having a size within the range of 50% to 70%, wherein the auxiliary control pin is installed within a distance of 50% of the length from the flow control pin in the direction of the stern.

[0020] The marine flow control system according to the present invention generates a swirling flow opposite to the propeller rotation direction to effectively control the rotational speed of the flow entering the propeller and recover energy loss, thereby increasing propulsion efficiency.

[0021] FIG. 1 is a perspective view showing the installation state of a flow control pin of a flow control system for a ship according to an embodiment of the present invention and the direction of seawater flow resulting therefrom.

[0022] FIG. 2 is a rear perspective view showing the installation state of a flow control pin of a flow control system for a ship according to an embodiment of the present invention and the direction of seawater flow resulting therefrom.

[0023] FIG. 3 is a side perspective view showing the installation state of a flow control pin of a flow control system for a ship according to an embodiment of the present invention and the direction of seawater flow resulting therefrom.

[0024] FIG. 4 is a perspective view of a flow control pin of a flow control system for a ship according to an embodiment of the present invention.

[0025] FIG. 5 is a side view showing a configuration in which only a flow control pin is installed in a flow control system for a ship according to an embodiment of the present invention.

[0026] FIG. 6 is a side view showing a configuration in which a flow control pin and an auxiliary control pin are installed in a flow control system for a ship according to an embodiment of the present invention.

[0027] FIG. 7 is a side view showing a configuration in which a flow control pin, an auxiliary control pin, and a rear control pin are installed in a flow control system for a ship according to an embodiment of the present invention.

[0028] Figures 8a to 8c are graphs showing the numerical analysis results of a flow control pin having a rectangular shape.

[0029] Figures 9a to 9c are graphs showing the numerical analysis comparison results of a flow control pin having a ladder-like shape.

[0030] FIGS. 10a to 10c, FIGS. 11a to 11c, FIGS. 12a to 12c, FIGS. 13a to 13c, and FIGS. 14a to 14c are graphs comparing numerical analysis results according to changes in the installation position of the flow control pin.

[0031] FIGS. 15a to 15c, FIGS. 16a to 16c, and FIGS. 17a to 17 are graphs comparing the results of numerical analysis according to the variation in the number of installed flow control pins.

[0032] FIGS. 18 and 19 are perspective views of a modified flow control pin in a flow control system for a ship according to a first modified embodiment of the present invention.

[0033] FIGS. 20 and 21 are perspective views of a modified flow control pin in a flow control system for a ship according to a second modified embodiment of the present invention.

[0034] <Explanation of Symbols>

[0035] 110: Flow control pin 110a: Inner plate

[0036] 110b: Outer plate 111: Inner side

[0037] 111a: 1st inner side 111b: 2nd inner side

[0038] 112: Lateral side 112a: First lateral side

[0039] 112b: Second lateral side 113: Anterior side

[0040] 113a: 1st forward side 113b: 2nd forward side

[0041] 114: Rear side 114a: First rear side

[0042] 114b: Second rear side 115: Fold line

[0043] 110c, 110d: Triangular plate 120: Auxiliary control pin

[0044] 130: Rear control pin

[0045] A flow control system for ships according to embodiments of the present invention will be described in detail with reference to the attached drawings. Since the present invention is susceptible to various modifications and may take various forms, specific embodiments are illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to the specific disclosed forms, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the present invention. Similar reference numerals have been used for similar components in the description of each drawing. In the attached drawings, the dimensions of the structures are shown enlarged or reduced to the actual size to ensure clarity of the present invention or to allow for understanding of the schematic configuration.

[0046] Additionally, terms such as "first," "second," etc., may be used to describe various components, but said components should not be limited by said terms. These terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be named the second component, and similarly, the second component may be named the first component. Meanwhile, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application.

[0047] <Example>

[0048] FIG. 1 is a perspective view showing the installation state of a flow control pin of a flow control system for a ship according to an embodiment of the present invention and the direction of seawater flow resulting therefrom; FIG. 2 is a rear perspective view showing the installation state of a flow control pin of a flow control system for a ship according to an embodiment of the present invention and the direction of seawater flow resulting therefrom; FIG. 3 is a side perspective view showing the installation state of a flow control pin of a flow control system for a ship according to an embodiment of the present invention and the direction of seawater flow resulting therefrom; FIG. 4 is a perspective view of a flow control pin of a flow control system for a ship according to an embodiment of the present invention.

[0049] As described above, the flow control system for a ship according to an embodiment of the present invention includes a flow control pin (110) installed in the port stern curve of the ship located in front of the propeller as a main component, thereby generating a counterclockwise swirling flow opposite to the rotation direction of the propeller, so as to improve the propulsion efficiency of the ship without increasing cavitation and hull fluctuation pressure occurring on the upper starboard side of the ship.

[0050] Hereinafter, a flow control system for a ship according to an embodiment of the present invention will be described in detail, focusing on the above-mentioned flow control pin (110).

[0051] The above flow control fin (110) is attached such that its inner side (111) aligns with the basic flow direction of the seawater at the port stern curve of the vessel, and is formed in a twisted shape that slopes downward toward the rear as it extends toward the outer end, thereby guiding the flow direction of the seawater toward the lower side of the propeller. It can be noted that in this configuration of the flow control fin (110), the basic flow direction of the seawater is maintained as is near the hull, while gradually changing toward the outer side. By doing so, the flow direction of the seawater is guided toward the lower side of the propeller, thereby generating a counterclockwise swirling flow while minimizing the resistance of the seawater caused by the flow control fin (110).

[0052] As can be seen in FIGS. 1 and 3, the inner side (111) of the flow control pin (110) is formed to be inclined upward toward the rear along the basic flow direction of the seawater, and the outer side (112) of the twisted flow control pin (110) is formed to be inclined downward toward the rear. Referring to FIG. 2, it can be seen that even in the case of seawater moving along the basic flow direction with a laminar flow form from the inside due to the flow control pin (110), it moves to the lower side of the propeller under the influence of seawater flowing in a turbulent form from the outside as it approaches the vicinity of the propeller.

[0053] The above flow control pin (110) can be manufactured by twisting a rectangular plate so that the outer side (112) is formed to slope downward toward the rear relative to the inner side (111) as shown in FIG. 4. No additional work such as bending specific sides or sheet metal work is required. Thus, a flow control pin (110) having a shape that gradually becomes twisted from the inner side (111) to the outer side (112) can be manufactured very simply, and at this time, the inner side (111), outer side (112), front side (113), and rear side (114) of the flow control pin (110) are all formed in a straight line shape. When comparing a rectangular flow control fin (110) with a trapezoidal fin made by removing the inner side area attached to the hull, the numerical analysis results can be seen in FIGS. 8a to 8c and FIGS. 9a to 9c, which confirm that the rectangular flow control fin (110) not only reduced the resistance of seawater compared to the trapezoidal fin but also improved the circulation strength overall.

[0054] It is preferable that the above flow control pin (110) be formed to have a length in the range of 1% to 3% of the ship's length and a width in the range of 2% to 10% of the ship's width. It is considered preferable that the installation location of the above flow control pin (110) be within the range of 10% to 25% of the ship's length from the stern waterline toward the bow, and within 50% of the planned draft height from the bottom of the ship.

[0055] The results of numerical analysis performed while changing the longitudinal position at a height of 1.1 waterline in relation to the installation position of the above flow control pin (110) can be confirmed through the flow velocity distribution graph, vortex circulation graph, and RTM increase graph attached in FIGS. 10a to 14c. FIGS. 10a to 10c show the results of numerical analysis for the case of Station 1.0, FIGS. 11a to 11c for the case of Station 2.0, FIGS. 12a to 12c for the case of Station 3.0, FIGS. 13a to 13c for the case of Station 4.0, and FIGS. 14a to 14c for the case of Station 5.0.

[0056] Through these graphs, it can be said that when the length of the ship is 20 stations, the effect is achieved when the flow control fin (110) is attached at least 1.5 stations after the stern waterline based on a waterline of 1.1. Considering that the propeller generally exhibits the greatest propulsion efficiency at 0.7R, it was confirmed that it is most desirable to attach the flow control fin (110) at 2.0 to 3.0 stations.

[0057] The above flow control pin (110) is attached along the basic flow direction of seawater at an angle of less than 30 degrees in the direction of the deck relative to the horizontal plane of the bottom of the ship, and is applied when the inner side (111) of the flow control pin (110) is attached to the port side stern curve of the ship as described above. In this state where the inner side (111) is attached, the flow control pin (110) is made to have a twist angle in the range of 10 to 30 degrees as it moves outward along the central axis, so that the flow direction of the seawater is directed downward toward the rear.

[0058] A flow control system for a ship according to an embodiment of the present invention can achieve sufficient effects even if it consists of only one flow control pin (110) as shown in FIG. 5. However, as shown in FIG. 6, the increase in RTM and the effect of reducing resistance can be enhanced by a configuration that additionally includes an auxiliary control pin (120). The auxiliary control pin (120) is configured to have the same shape as the flow control pin (110) and to have a size within the range of 50% to 70%. The auxiliary control pin (120) is installed within a distance of 50% of the length from the flow control pin (110) in the direction of the stern.

[0059] Meanwhile, as shown in FIG. 7, in addition to the auxiliary control pin (120), a rear control pin (130) may be installed at a distance toward the stern. The rear control pin (130) may be the same size as the auxiliary control pin (120) or slightly smaller in size, and may be installed in a straight line with the flow control pin (110) and the auxiliary control pin (120). As can be seen in FIG. 17a to 17c, when three control pins including the rear control pin (130) are installed, the increase in RTM and the reduction in resistance are compared to when only the flow control pin (110) is installed.

[0060] The results of numerical analysis when an auxiliary control pin (120) and a rear control pin (130) are additionally installed in addition to the above-mentioned flow control pin (110) can be confirmed through the flow velocity distribution graph, vortex circulation graph, and RTM increase amount graph attached to FIGS. 15a to 17c. FIGS. 15a to 15c show the results of numerical analysis when only the flow control pin (110) is installed, FIGS. 16a to 16c show the results when the flow control pin (110) and the auxiliary control pin (120) are installed, and FIGS. 17a to 17c show the results of numerical analysis when the rear control pin (130) is installed in addition to the flow control pin (110) and the auxiliary control pin (120).

[0061] Through these graphs, it was confirmed that while increasing the number of control pins generally increases the resistance of the vessel, there is an increase in rotation of more than 40% at 0.7R compared to when only one control pin is installed. It is expected that by undergoing an optimization process of attaching control pins in combination, it is possible to obtain a large amount of rotation while minimizing the increase in resistance.

[0062] A ship flow control system according to a modified embodiment of the present invention will be described further.

[0063] FIGS. 18 to 19 are perspective views of a modified flow control pin in a ship flow control system according to a first modified embodiment of the present invention.

[0064] As described above, the first modified embodiment of the present invention is characterized by a flow control pin (110) comprising an inner plate (110a) attached to the port stern curve of the ship so as to align with the basic flow direction of seawater, and an outer plate (110b) attached to the inner plate (110a) so as to be inclined downward toward the rear relative to the inner plate (110a) to guide the flow direction of seawater toward the lower side of the propeller.

[0065] Here, the first outer side (112a) of the inner plate (110a) and the second inner side (111b) of the outer plate (110b) intersect in an X shape, and the space between the first outer side (112a) of the inner plate (110a) and the second inner side (111b) of the outer plate (110b) is filled by joining two triangular plates (110c, 110d). Thus, the inner plate (110a) is responsible for guiding seawater in the basic flow direction, and the outer plate (110b) is responsible for guiding seawater to the lower side of the propeller. In the case of the flow control fin (110) deformed into a knuckle shape in this way, the same effect can be expected in that it improves propulsion efficiency by generating a counterclockwise swirling flow opposite to the rotation direction of the propeller compared to before the deformation. However, since the inner plate (110a) is clearly separated to guide seawater in the basic flow direction and the outer plate (110b) is clearly separated to guide seawater to the lower side of the propeller, the installation angle required for each can be clearly set, which has the relative advantage of being easy to design, but it also has the disadvantage of high resistance to seawater. Two triangular plates (110c, 110d) joined to fill the space between the first outer side (112a) of the inner plate (110a) and the second inner side (111b) of the outer plate (110b) help to minimize the increase in seawater resistance caused by the shape of the inner plate (110a) and the outer plate (110b) intersecting.

[0066] As other configurations not mentioned in relation to the first modified embodiment described above are substantially similar to the embodiment prior to modification, further explanation is omitted.

[0067] FIGS. 20 to 21 are perspective views of a modified flow control pin in a ship flow control system according to a second modified embodiment of the present invention.

[0068] As described above, in the second modified embodiment of the present invention, the inner side (111) of the flow control pin (110) is attached to the port stern curve of the ship so as to align with the basic flow direction of the seawater, and is formed in a shape that is twisted and bent so as to slope downward toward the rear in the middle part between the inner side (111) and the outer side (112), thereby guiding the flow direction of the seawater toward the lower side of the propeller. The front side (113) of the flow control pin (110) is formed in a straight shape, and the rear side (114) is bent at a maximum angle to maximize the flow control effect.

[0069] As such, the flow control pin (110) according to the second modified embodiment can be expected to have the same effect as the embodiment prior to modification in that it improves propulsion efficiency by generating a counterclockwise swirling flow opposite to the rotation direction of the propeller. However, while it has a relative advantage in that the design is easy because the angles of the inner and outer parts can be clearly set from the rear side by simply bending a single plate, it has a disadvantage in that resistance to seawater may increase.

[0070] As other components not mentioned in relation to the aforementioned second modified embodiment are substantially similar to the embodiment prior to modification, further explanation is omitted.

[0071] Although preferred embodiments of the present invention have been described above, the present invention may use various variations, modifications, and equivalents. It is clear that the present invention can be applied in the same way by appropriately modifying the above embodiments. Therefore, the above description does not limit the scope of the present invention, which is defined by the limitations of the following claims.

Claims

1. A flow control system for a ship characterized by including a flow control fin installed at an angle facing downward relative to the basic flow direction of seawater in the port stern curve of the ship located in front of the propeller, which induces the flow direction of seawater to face downward relative to the propeller, thereby generating a counterclockwise swirling flow opposite to the rotation direction of the propeller, so as to improve the propulsion efficiency of the ship without increasing cavitation and hull fluctuation pressure occurring on the upper starboard side of the ship.

2. In Paragraph 1, A ship flow control system characterized by the above-mentioned flow control fin being attached to the inner side of the port stern curve of the ship so as to align with the basic flow direction of seawater, and being formed in a twisted shape that slopes downward toward the rear as it extends toward the outer end to guide the flow direction of seawater toward the lower side of the propeller.

3. In Paragraph 2, A ship flow control system characterized by the above-mentioned flow control pin being formed in the shape of a rectangular plate, with a shape that gradually twists from the inner side to the outer side.

4. In Paragraph 3, A flow control system for a ship, characterized in that the above-mentioned flow control pin has an inner side, an outer side, a front side, and a rear side all formed in a straight line shape.

5. In Paragraph 1, A ship flow control system characterized by the above-mentioned flow control fin comprising an inner plate attached to the port stern curve of the ship to align with the basic flow direction of seawater, and an outer plate attached to the inner plate so as to be inclined downward toward the rear relative to the inner plate to guide the flow direction of seawater toward the lower side of the propeller.

6. In Paragraph 5, A ship flow control system characterized in that the first outer side of the inner plate and the second inner side of the outer plate intersect in an X shape, and the space between the first outer side of the inner plate and the second inner side of the outer plate is filled by joining two triangular plates to reduce seawater resistance.

7. In Paragraph 1, A ship flow control system characterized by the above-mentioned flow control fin being attached such that its inner side aligns with the basic flow direction of seawater at the port stern curve of the ship, and having a shape that is twisted and bent so as to slope downward toward the rear from the middle section between the inner side and the outer side to guide the flow direction of seawater toward the lower side of the propeller.

8. In Paragraph 7, A marine flow control system characterized in that the front side of the above-mentioned flow control pin is formed in a straight shape, and the rear side is bent at a maximum angle to maximize the flow control effect.

9. In Paragraph 2, A flow control system for a ship, characterized in that the above-mentioned flow control fin is formed to have a length in the range of 1% to 3% of the ship's length and a width in the range of 2% to 10% of the ship's width.

10. In Paragraph 2, A flow control system for a ship, characterized in that the above-mentioned flow control fin is located within 10% to 25% of the ship's length from the stern waterline towards the bow and within 50% of the planned draft height from the bottom of the ship.

11. In Paragraph 2, A flow control system for a ship, characterized in that the above-mentioned flow control fin is attached along the basic flow direction of seawater at an angle of within 30 degrees in the deck direction relative to the horizontal plane of the bottom of the ship, and has a twist angle ranging from 10 to 30 degrees as it extends outward along the central axis of the flow control fin.

12. In Paragraph 2, A ship flow control system characterized by further including an auxiliary control fin having the same shape as the above flow control fin and having a size within the range of 50% to 70%, wherein the auxiliary control fin is installed within a distance of 50% of the length from the flow control fin in the direction of the stern.

13. A vessel characterized by having the flow control system for a vessel according to claim 1.

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