JP2023164133A - Fin device and vessel - Google Patents

Abstract

To provide a fin device and a vessel capable of saving energy by improving propulsion efficiency of a vessel provided with a bossing projecting downward from a bottom of a stern unit.SOLUTION: A vessel 1 is a fine type vessel including a bossing 12 projecting downward from a stern unit 11 and a hull plane unit 13 with shipboard surfaces on both quarters formed approximately in parallel from a top end to a bottom end. A fin device 2 includes a fin 21 arranged on a side surface of the bossing 12. A front end unit 22 of the fin 21 is arranged in a range of a bilge height R from a bottom 16 of the hull flat surface unit 13 as well as within a range where square station S.S is 1.0 to 1.5.SELECTED DRAWING: Figure 2

Description

The present invention relates to a fin device and a ship, and particularly to a fin device suitable for saving energy in a slim ship, and a ship equipped with the fin device.

In recent years, from the viewpoint of environmental issues such as soaring crude oil prices and reductions in carbon dioxide emissions, there has been an increasing demand for improved fuel efficiency for ships, and further energy savings are being sought. Incidentally, a bilge vortex (separated vortex) is generally generated at the stern of the ship, and by collecting this bilge vortex with a propeller, propulsion efficiency can be improved.

As a device for collecting this bilge vortex, for example, there is a device in which a substantially cylindrical duct is placed just in front of the propeller (see Patent Document 1), and a device in which fins are placed on the side of the hull (see Patent Document 2). Already proposed.

In the duct device described in Patent Document 1, by taking the water flow (wake) containing the bilge vortex into the duct, the flow of the water flow can be rectified in the axial direction, and the bilge vortex can be efficiently recovered. can.

Furthermore, in the fin device described in Patent Document 2, by arranging a plurality of fins within a predetermined range of the stern, the vortices generated by the fins disturb the slow speed zone and form the slow speed zone. Water flow can be concentrated and guided to the propeller, improving propulsion efficiency.

Patent No. 5132140 Patent No. 6351700

By the way, the shape of a ship is generally classified into an oversized ship with a large squareness coefficient CB, which indicates the degree to which the volume of the hull below the waterline is lean, and a thin ship with a small squareness coefficient CB. The enlarged ship is often applied to, for example, a tanker or a bulk carrier. Furthermore, the slim ship is often applied to, for example, a container ship.

In slim ships, when an appendage is placed just in front of the propeller, like the duct device described in Patent Document 1, it is often not installed because the effect of improving propulsion efficiency is small. In addition, when the fin device is arranged near the side flat of the hull, as in the fin device described in Patent Document 2, it is effective against the slow speed zone formed at the bottom of the ship at the stern. The slow flow that passes through the sides of the bossing that protrudes downward from the bottom of the ship cannot be guided to the propeller.

The present invention was devised in view of such problems, and provides a fin device and a slim ship that can improve the propulsion efficiency and save energy of a ship equipped with a bossing projecting downward from the stern. The purpose is to

According to the present invention, there is provided a fin device disposed on a slim ship, which includes a bossing projecting downward from the stern, and a hull plane portion in which the ship sides of both bowstrings are formed substantially parallel from the upper end to the lower end. and has a fin disposed on a side surface of the bossing, the front end of the fin being within a bilge height range from the bottom of the flat surface of the hull and having a square station of 1.0 to 1.5. A fin device is provided, characterized in that the fin device is arranged in a fin device.

The front end of the fin may have a square station arranged within a range of 1.1 to 1.4.

The fin may have a wing-shaped cross section, and may be configured such that the rear end portion is located above the front end portion.

The rear end portion of the fin may be disposed within a range of bilge height from the bottom of the flat surface portion of the hull.

It may have one or more preceding fins arranged in front of and above the fins.

The thin ship has, for example, a squareness factor of 0.75 or less or 0.8 or less.

Further, according to the present invention, there is provided a ship characterized by having a fin device having any of the configurations described above.

According to the above-described fin device and ship according to the present invention, by arranging the predetermined fins on the side surface of the bossing of a slim ship, the propulsion efficiency of a ship equipped with a bossing protruding downward from the stern part can be improved and energy can be saved. It is possible to aim for

FIG. 1 is a perspective view showing a ship equipped with a fin device according to a first embodiment of the present invention. FIG. 2 is a side view showing the stern of the ship shown in FIG. 1. FIG. It is explanatory drawing of a fin, (A) is a side view, (B) is a top view. FIG. 4 is an explanatory diagram showing changes in the improvement effect with respect to the position of the fin, where (A) shows 1-t (thrust reduction coefficient) and (B) shows 1-wt (effective wake coefficient). FIG. 3 is a wake distribution diagram on the propeller surface when the propeller is not operating. It is an analytical diagram of the water flow flowing on the side surface of the bossing, and (A) shows the case without fins, and (B) shows the case with fins. FIG. 2 is a perspective view showing the hull structure of an enlarged ship as a comparative example. It is a figure showing an improvement rate of a ship provided with a fin device concerning a first embodiment. It is a perspective view showing a ship provided with a fin device concerning a second embodiment of the present invention.

Embodiments of the present invention will be described below using FIGS. 1 to 9. Here, FIG. 1 is a perspective view showing a ship equipped with a fin device according to a first embodiment of the present invention. FIG. 2 is a side view showing the stern of the ship shown in FIG. 1. FIG. FIG. 3 is an explanatory diagram of the fin, in which (A) is a side view and (B) is a plan view. For convenience of explanation, as shown in FIG. 1, the ship length direction is defined as the X axis, the transverse direction as the Y axis, and the vertical direction as the Z axis.

The ship 1 according to the first embodiment is a slim ship that includes a bossing 12 projecting downward from the stern part 11 and a hull plane part 13 in which the ship side surfaces of both chords are formed substantially parallel from the upper end to the lower end. For example, it includes the fin device 2 shown in FIGS. 1 to 3(B).

The shape of the ship 1 is generally classified into an enlarged ship with a large squareness coefficient CB, which indicates the degree of leanness of the volume below the waterline of the ship, and a thin ship with a small squareness coefficient CB. In this specification, a lean ship is defined as a ship shape with a squareness coefficient CB of 0.75 or less, or a ship shape with a squareness coefficient CB of 0.8 or less.

In addition, the squareness factor is generally calculated as the volume of the inside of the hull below the waterline of a ship at a certain draft, and the length, width, and height, respectively, as the length of the hull, the maximum width of the inside of the hull, and the distance from the waterline to the keel. It is expressed as the ratio of the vertical distance to the top surface and the volume of the rectangular parallelepiped.

The ship 1, which is a thin ship, has, for example, a shape in which the hull plane part 13 extends in parallel to the stern part 11, and the ship width of the stern part 11 is formed to be larger than the ship width of the enlarged ship. As shown in FIG. 2, a propeller 15 is disposed below the bottom 14 of the stern section 11 and behind the bossing 12, and inside the bossing 12, the engine power is mainly transmitted to the propeller 15. A propeller shaft (not shown) is inserted therethrough. Further, a rudder 17 is arranged behind the propeller 15.

In this specification, the hull plane part 13 means a part where the port and starboard sides of the ship are formed substantially parallel to each other from the upper end to the lower end, as shown in FIGS. 1 and 2. They are connected by a curved surface with a hull bilge height R. The bottom 14 of the stern section 11 is connected to the bottom 16 of the ship by a smooth curved surface.

The fin device 2 has fins 21 arranged on the side surface of the bossing 12. For example, one fin 21 is arranged on the port side and one on the starboard side. For example, as shown in FIG. 3A, the fin 21 has a wing-shaped cross section and has an angle of attack α such that the rear end 23 is located above the front end 22. With this configuration, the resistance of the fins 21 can be reduced, and the vortex generated at the front end portion 22 can be easily guided to the propeller 15.

Further, as shown in FIGS. 3A and 3B, for example, the fin 21 has a substantially trapezoidal shape in plan view, and has a tip end relative to the width c1 of the root portion 24 connected to the hull. The width c2 of the portion 25 is formed to be shorter in the longitudinal direction. With this configuration, it is possible to reduce the resistance accompanying the increase in flow velocity on the side of the tip portion 25 of the fin 21.

Further, the height b (length in the width direction) of the fin 21 is set within a range that does not exceed the width of the hull (a range that does not protrude outward beyond the hull plane portion 13). Note that the shape of the fins 21 is not limited to the illustrated configuration.

For example, as shown in FIG. 2, the front end portion 22 of the fin 21 is within the range of the bilge height R from the bottom 16 of the hull plane portion 13 and within the square station S. S. is placed within the range of 1.0 to 1.5. Square Station S. S. (Square Station) means the vertical plane that divides the length of the waterline of a ship into 10. In addition, in the figure, W. L. indicates the water line.

Also, Square Station S. S. The position of stern perpendicular A. P. (After Perpendicular) is set to 0, and the bow perpendicular F. P. (Forward Perpendicular) is set as 10 and is quantified toward the ship's ship direction (X-axis direction). In FIG. 2, Square Station S. S. The positions of =1.0, 1.1, 1.4, 1.5, and 2.0 are shown with dotted lines.

Also, the bow perpendicular F. P. From stern perpendicular A. P. For example, the width c1 of the root portion 24 of the fin 21 is about 1.5 to 2% of the perpendicular length Lpp, and the length in the longitudinal direction (X-axis direction) up to The width c2 of 25 is set to about 0.5 to 1.0% of the length Lpp between perpendicular lines.

Further, the rear end portion 23 of the fin 21 may be arranged within a range of the bilge height R from the bottom 16 of the hull plane portion 13, as shown in FIG. However, the rear end portion 23 of the fin 21 may be located at a position exceeding the range of the bilge height R.

Here, FIG. 4 is an explanatory diagram showing changes in the improvement effect with respect to the position of the fin, where (A) shows 1-t (thrust reduction coefficient), and (B) shows 1-wt (effective wake coefficient). It shows. The test results shown in FIGS. 4(A) and 4(B) show the results of changing the position of the fin in the longitudinal direction using a model of the stern part.

In the test results in FIG. 4(A), the horizontal axis is square station S. S. , the vertical axis indicates 1-t (thrust reduction coefficient), and the numerical value increases from the bottom to the top of the vertical axis. As the value of 1-t (thrust reduction coefficient) increases, the improvement effect tends to increase. S. It can be said that a range of 0.5 to 1.5 is preferable.

In the test results in FIG. 4(B), the horizontal axis is square station S. S. , the vertical axis indicates 1-wt (effective wake coefficient), and the numerical value increases from the bottom to the top of the vertical axis. 1-wt (effective wake coefficient) tends to have a larger improvement effect as the value becomes smaller. S. It can be said that a range of 1.0 to 2.0 is preferable.

1-t (thrust reduction coefficient) and 1-wt (effective wake coefficient) are one of the self-propulsion factors (values representing interference between the propeller and the hull), and it is preferable to improve both values. Therefore, from the test results shown in FIGS. 4(A) and 4(B), the position of the front end portion 22 of the fin 21 is 1.0≦S. S. It is preferable to set it in the range of ≦1.5. More preferably, the position of the front end portion 22 of the fin 21 is 1.1≦S. S. It may be set within the range of ≦1.4.

Here, FIG. 5 is a wake distribution diagram on the propeller surface in a state where the propeller is not operating. In the figure, the circular thick line P is the propeller surface, the solid thin line Q is the wake distribution of a ship without fins corresponding to the fins 21 according to this embodiment, and the dotted line R is the wake of this embodiment with fins 21. It shows the distribution.

As shown in the figure, the wake distribution indicated by the thin line Q is generally distributed such that the flow velocity increases as the distance from the ship increases. Note that the numbers from 0.1 to 0.5 in the figure indicate the wake rate, which means that the larger the number, the slower the flow velocity.

On the other hand, in the ship according to the present embodiment having the fins 21, as shown by the dotted line R, a region V (for example, a portion filled in gray) where the flow velocity is slow can be formed within the propeller surface (thick line P). I understand that. This means that the vortex formed by the fins 21 is guided by the propeller 15 and collected. Therefore, by arranging the fins 21, it is possible to intentionally generate a vortex to expand an area where the flow velocity is low to stabilize the flow of water, and the vortex can be collected by the propeller 15.

Here, FIG. 6 is an analytical diagram of the water flow flowing on the side surface of the bossing, in which (A) shows the case without fins, and (B) shows the case with fins. As shown in the figure, when a part of the water flow flowing on the side surface of the bossing 12 is analyzed, it is found that when there are no fins as shown in FIG. 6(A), the water flow flows toward the water surface and cannot be collected by the propeller 15. Recognize.

On the other hand, when there are fins 21 as shown in FIG. 6(B), it can be seen that the water flow is disturbed by the fins 21 and collected by the propeller 15.

Next, regarding the fin device 2 according to the first embodiment, the difference in effects between a thin ship and an enlarged ship will be explained. Here, FIG. 7 is a perspective view showing the hull structure of an enlarged ship as a comparative example. FIG. 8 is a diagram showing the improvement rate of a ship equipped with the fin device according to the first embodiment. In FIG. 8, the white bar graph shows the improvement rate for thin ships, and the gray bar graph shows the improvement rate for fat ships.

The enlarged ship 101, which is a comparative example, includes a bossing 112 that protrudes downward from the stern part 111, and a hull plane part 113 in which the ship sides of both chords are formed substantially parallel from the upper end to the lower end, and the squareness factor is A vessel with a hull form with a CB greater than 0.75 or 0.8.

As shown in FIG. 7, the enlarged ship has, for example, a shape in which the width of the ship narrows from the flat surface part 113 of the hull to the rear of the stern part 111. Furthermore, in order to compare the improvement rate with this embodiment, fins 121 are provided on both sides of the bossing 112.

FIG. 8 shows the results of an aquarium test on the model ship 1 (skinny ship) shown in FIG. 1 and the enlarged ship 101 shown in FIG. 6. Moreover, the vertical axis of FIG. 8 shows the improvement effect (%), and a positive value indicates that there is an improvement effect, and a negative value indicates that there is no improvement effect. The horizontal axis shows the test items, and from the left, effective horsepower, 1-t (thrust reduction coefficient), 1-wt (effective wake coefficient), and shaft horsepower.

Regarding the item of effective horsepower, no improvement effect was observed for both Ship 1 (slim ship) and Huge Ship 101. Regarding the item 1-t (thrust reduction coefficient), an improvement effect was seen for both Vessel 1 (skinny ship) and bloated ship 101, but the improvement was greater for Vessel 1 (skinny ship) than for slender ship 101. The results were very effective.

In terms of 1-wt (effective wake coefficient), an improvement effect was seen for both Vessel 1 (skinny ship) and fat ship 101, but Vessel 1 (skinny ship) had a better effect than fat ship 101. The results showed a significant improvement effect. Regarding the shaft horsepower item, while an improvement effect was seen in Ship 1 (slim ship), no improvement effect was seen in enlarged ship 101.

Shaft horsepower means the output (horsepower) that can actually be used as power out of the power generated by the propulsion device, so by ultimately comparing the shaft horsepower, the effectiveness of the fin device 2 can be evaluated. can be evaluated. That is, the fin device 2 according to the first embodiment described above can improve the propulsion efficiency of a thin ship and save energy.

Next, a ship 1 equipped with a fin device 2 according to a second embodiment of the present invention will be described with reference to FIG. 9. Here, FIG. 9 is a perspective view showing a ship equipped with a fin device according to a second embodiment of the present invention. Note that the same components as those in the first embodiment described above are given the same reference numerals and redundant explanations will be omitted.

A ship 1 according to the second embodiment shown in FIG. 9 includes a first leading fin 31 and a second leading fin 32 that are arranged ahead and above the fins 21. The second leading fin 32 is arranged rearward and above the first leading fin 31. Further, the first leading fin 31 and the second leading fin 32 have a flat plate shape that extends substantially horizontally in the ship width direction, and are configured so as not to protrude from the hull plane portion 13 .

In this way, by configuring the fin device 2 to include the leading fins (the first leading fins 31 and/or the second leading fins 32) preceding the fins 21, the slow flow rate that remains at the bottom 14 of the stern part 11 can be reduced. The slow speed zone can be disturbed by the vortices generated by the leading fins, and the water flow forming the slow speed zone can be concentrated and guided to the propeller.

As in the ship 1 according to the second embodiment, by arranging the leading fins ahead and above the fins 21, the effects of the fins 21 and the leading fins can be enjoyed without interfering with each other. .

It goes without saying that the present invention is not limited to the embodiments described above, and that various changes can be made without departing from the spirit of the present invention.

1 Ship 2 Fin device 11 Stern part 12 Bossing 13 Hull plane part 14 Bottom part 15 Propeller 16 Bottom 21 Fin 22 Front end part 23 Rear end part 24 Root part 25 Tip part 31 First leading fin 32 Second leading fin 101 Enlarged ship 111 Stern Part 112 Bossing 113 Hull flat part 121 Fin

Claims (7)

A fin device disposed on a slim ship, comprising a bossing projecting downward from the stern, and a hull plane portion in which the ship sides of both chords are formed substantially parallel from the upper end to the lower end, the fin device comprising:
fins disposed on the sides of the bossing;
The front end of the fin is located within a bilge height range from the bottom of the flat surface of the hull and within a square station of 1.0 to 1.5,
A fin device characterized by: The fin device according to claim 1, wherein the front end of the fin has square stations arranged within a range of 1.1 to 1.4. The fin device according to claim 1, wherein the fin has a wing-shaped cross section and has an angle of attack such that the rear end is located above the front end. The fin device according to claim 1, wherein the rear end portion of the fin is disposed within a range of bilge height from the bottom of the flat surface portion of the hull. The fin device according to claim 1, further comprising one or more leading fins disposed in front of and above the fins. The fin device according to claim 1, wherein the thin boat has a squareness factor of 0.75 or less, or 0.8 or less. A ship comprising the fin device according to any one of claims 1 to 6.