JP5025247B2 - Ship duct and ship with ship duct - Google Patents

Description

  The present invention relates to a marine duct installed at the stern of a marine vessel and a marine vessel with a marine duct in which the marine duct is installed.

  In a ship, a device that collects energy lost when the hull moves forward and obtains an energy-saving effect is a kind of energy-saving device, a cylindrical device (called a duct or nozzle) installed in front of the propeller. (For example, see Patent Documents 1 and 2).

Utility Model Registration Gazette No. 2555130 (2 pages, FIG. 1) JP 11-278383 A (page 2-3, FIG. 2)

However, the device disclosed in Patent Document 1 is provided by providing a ring-shaped nozzle of a prescribed shape (same as a ship duct, hereinafter referred to as a “ship duct”) between the stern of the hull and the propeller. Although the hull efficiency and propulsion efficiency can be improved, the shape of the cross section including the shaft center of the ship duct (hereinafter referred to as “cross-sectional shape”) is hydrodynamically streamlined as typified by an airfoil. Because of its shape, it is a three-dimensionally complicated curved surface. In particular, the front edge of the duct (the bow side edge) has a bent portion with a large curvature (same as a small radius of curvature) in the cross section including the shaft center, and also has a circular arc shape in the cross section perpendicular to the shaft center. It is bent. For this reason,
(A) “Linear heating”, in which bending is performed while applying heat, requires skilled processing skills, and has the problem that the number of processing steps increases significantly compared to breath processing, and craftsmen with skilled processing skills Therefore, there is a problem that it may not be a processing method in the future.
(Ii) In addition, the upper side of the bow side edge of the marine duct is chipped, that is, the stern side edge of the marine duct is a ring, whereas the bow side edge of the marine duct is Since it is substantially C-shaped and is only connected to both sides of the hull at the missing part, there is a problem that the rigidity of the duct is low and vibration is likely to occur.

Moreover, the invention disclosed in Patent Document 2 is to form an extremely thick steel plate into an annular shape by press working and shape its cross-sectional shape into a wing shape by machining. For this reason,
(Iii) Since the cost of machining is high, there is a problem that the manufacturing cost increases.
(E) In addition, since machines that enable such machining are limited to specific machines, there are limited factories that can be manufactured, and there is a problem of increased transportation costs and extension of the work period due to processing waiting. .
(O) Also, although the stern boss supporting the propeller and the upper inner surface of the ship duct are connected by a wing-type strut, the duct rigidity is not sufficiently high, and vibration is likely to occur. Was unresolved. In addition, since the marine duct (substantially annular portion) and the struts are both wing-shaped in cross section and are formed by machining, there is a problem that the machining cost increases.

  The present invention has been made in view of the above, and a marine duct capable of suppressing the production cost and preventing the occurrence of vibration while maintaining the performance as an energy saving device, and the marine duct are installed. A ship with a ship duct is provided.

(1) A ship duct according to the present invention is a ship duct installed at the stern of a hull,
A cylindrical duct skin whose bow side is larger than the stern side;
A cylindrical stern side inner plate connected to the stern side edge of the duct outer plate in a state accommodated in the duct outer plate;
A bow side inner plate that smoothly connects the bow side edge of the duct outer plate and the bow side edge of the stern side inner plate in a state of being accommodated in the duct outer plate;
Have a, a plurality of plate-shaped stays for connecting the stern-side inner plate and the hull,
A baffle plate parallel to the hull center plane is installed on the upper surface of the stay .

(2) In (1), the upper side of the duct outer plate is longer than the lower side, and the upper side of the stern side inner plate is longer than the lower side.
(3) In the above (1) or (2), the stern side inner plate is a part of a cylinder or a cone.
(4) In any one of (1) to (3), a pipe or a bar is installed along a bow side edge of the duct outer plate, and the bow of the bow side inner plate is installed on the pipe or the bar. The side edges are connected.

(5) A ship with a ship duct according to the present invention includes a hull,
A propeller installed protruding from the stern of the hull;
The marine duct according to any one of (1) to (4) installed at the stern of the hull;
Have

(I) Therefore, according to the present invention, the plate-like stay for connecting the stern side inner plate of the marine duct and the hull has a simple shape as compared with the wing-type stay, so that the production is easy. Further, since the simple-shaped plate-like stay is connected to the stern side inner plate (there is no portion having a large curvature), the joining is easy. Furthermore, since the marine duct is connected to the hull by a plurality of plate-like stays, generation of vibrations is prevented.
(Ii) Furthermore, since the duct outer plate and the stern side inner plate are longer on the upper side than the lower side in a side view, the degree of freedom of design corresponding to the stern shape increases, and the energy saving effect increases.
(Iii) Since the stern side inner plate is a part of a cylinder or a cone, that is, the ridge line is a straight line, the stern side inner plate can be manufactured by two-dimensional bending of a plate material, and a plurality of plate-like stays can be manufactured. Since they are connected to the straight ridgeline, the connecting operation is easy and quick, and the manufacturing cost and the construction period can be shortened.
(Iv) Since the pipe or bar is installed along the bow side edge of the duct outer plate, and the bow side edge of the bow side inner plate is connected to the pipe or bar, the bow side of the bow side inner plate Since a bending process with a large curvature at the edge (the same as when the curvature radius is small) is not required, the manufacturing is facilitated, and further reduction in the manufacturing cost and shortening of the construction period of the marine duct are promoted.

  (V) Furthermore, according to the present invention, since the marine duct according to any one of (1) to (4) is installed, the manufacturing cost can be reduced and the propulsion performance can be improved.

[Embodiment 1: Ship with ship duct]
FIG. 1: shows the outline | summary of the ship with a ship duct concerning Embodiment 1 of this invention, (a) is a partial side view, (b) is sectional drawing seen from the stern side. In FIG. 1, a ship with a ship duct 1 includes a hull 2, a propeller 3 installed to protrude from the stern (right side in the figure) of the hull 2, a ship duct 6 installed at the stern of the hull 2, have. The marine duct 6 includes a cylindrical duct 4 and a pair of stays 5 that connect the cylindrical duct 4 and the hull 2.

The outline of the cylindrical duct 4 is substantially trapezoidal in side view (same as the direction of viewing the ship side) (formed by a line segment connecting position A-position B-position D-position C in FIG. 1A). Thus, it is a part of a substantially conical shape having a circular cross section (see FIG. 1B) in a front view (same as the direction of viewing the stern).
It should be noted that the ship side edge of the tubular duct 4 (range away from the propeller 3) has a notch on the upper side (corresponding to the bridge side or the water surface side) and the lower side (corresponding to the ship bottom side or the sea floor side). Since it is formed and installed in the hull 2 at the notch, the cross section of the ship side edge of the cylindrical duct 4 is formed by a pair of substantially semicircular members. Moreover, the stern side edge part (range close to the propeller 3) of the cylindrical duct 4 is exhibiting the substantially C shape which the part connected to the skeg 9 missing.

The symmetry plane of the hull 2 is a chain line (hereinafter referred to as “hull center plane”) 2c, the center axis of the propeller 3 is a chain line (hereinafter referred to as “propeller axis”) 3c, and the central axis of the cylindrical duct 4 Is indicated by a dashed line (corresponding to the dashed line 3c, hereinafter referred to as “duct axis”) 4c, and an example of the water surface is indicated by a solid line (hereinafter referred to as “horizontal plane”) 1c.
When the diameter of the propeller 3 is “Dp” , the stern side diameter Dn of the cylindrical duct 4 (position C-distance D), the upper length Ld of the cylindrical duct 4 (the length of the line segment AC), the cylindrical shape The lower length Lb of the duct 4 (the length of the line segment BD) and the ratio of the diameter of the cylindrical duct 4 that expands in the bow direction (in the figure, the angle between the line segment AC and the duct shaft 4c, the line segment BD) And the duct shaft 4c (hereinafter referred to as “opening angle”) θd is constant in the circumferential direction and is in the following range.
0.40 × Dp ≦ Dn ≦ 1.0 × Dp
0.40 × Dp ≦ Ld ≦ 1.0 × Dp
0.02 × Dp ≦ Lb ≦ 1.0 × Dp
Lb ≦ Ld
5 ° ≦ θd ≦ 20 °

[Embodiment 2: Duct for ships-Part 1]
FIG. 2: shows the outline | summary of the ship duct which concerns on Embodiment 2 of this invention, (a) is a side view, (b) is the front view seen from the stern side. In addition, the same code | symbol is attached | subjected to this same part as Embodiment 1 (FIG. 1), and one part description is abbreviate | omitted.
In FIG. 2, the cylindrical duct 4 is installed in the starboard side of the ship 1 with a ship duct shown in FIG. The pair of stays 5 constituting the marine duct 6 are symmetrically installed on both sides of the hull 2 with “elevation angle αs” in a side view and “inclination angle θs” in a front view with respect to a horizontal plane 1c. Further, the center planes 5c (indicated by alternate long and short dash lines) of the pair of stays 5 intersect at the hull center plane 2c, and the intersection Q between the intersecting line and the plane including the stern side edge of the cylindrical duct 4 is a propeller. It is separated from the shaft 3c by a distance (hereinafter referred to as "deviation distance") Hs.

That is, when the distance between the cylindrical duct 4 and the stay 5 is reduced, the effect of the stay 5 is considered to be reduced. Therefore, in order to achieve a positional relationship in which the cylindrical duct 4 and the stay 5 do not interfere with each other, the following range is set. It is preferable to set.
−30 ° ≦ αs ≦ 30 °
−0.3 × Dn ≦ Hs ≦ 0.3 × Dn
−45 ° ≦ θs ≦ 45 °
FIG. 1 shows the following case.
αs = 0 °
Hs = 0
θs = 0 °

(Energy saving effect)
FIG. 3 is a perspective view schematically showing a marine duct used for confirming the energy saving effect of the marine vessel with the marine duct shown in FIG. 1, wherein (a) is a marine duct having a stay; b) is a cylindrical duct without a stay.
The tank used to confirm the effect of the stay 5 on the energy saving effect is a hull test tank of 240 m in length, 18 m in width, and 8 m in depth, and the size of the model ship is about 8 m. Is a large bulk carrier. The cross-sectional shape of the stay 5 is a flat plate having the same thickness as the cross-sectional shape of the cylindrical duct 4, and the cord length is the same as the cord length of the cylindrical duct 4 at the same height as the propeller shaft 3c.

Table 1 shows a horsepower comparison when the horsepower when the stay 5 is not attached (only the cylindrical duct 4 is installed) is “100”.
Compared with the case where only the cylindrical duct 4 (without the stay 5) is installed, when the marine duct 6 having the stay 5 is installed, about 1% horsepower is reduced. From this, it was confirmed that the energy saving effect was improved by attaching the stay 5. In this test, although the stay 5 is formed not by the airfoil cross section but by a flat plate, the energy saving effect is not deteriorated.
In addition, since the cylindrical duct 4 is installed in the hull, it is not exactly a perfect ring, but is formed from a circular arc portion with notches formed at two or one place.

FIG. 4 is a side view for explaining the energy saving effect of the ship with the ship duct shown in FIG. In addition, the same code | symbol is attached | subjected to this same part as FIG. 1, and one part description is abbreviate | omitted.
In FIG. 4, when the stay 5 is attached to the cylindrical duct 4, the distribution of the flow field flowing into the area behind the cylindrical duct 4 (indicated by hatching in FIG. 4) in front of the propeller 3 changes. The effective wake coefficient “1-Wt”, which is one of the self-propelled elements that determines the required horsepower, is improved. Therefore, compared with the case where only the cylindrical duct 4 without the stay 5 is installed, the horsepower reduction effect is improved.
Table 2 shows a comparison of “1-wt” in the test. The required horsepower is lower as 1-Wt is smaller, and in the test results, 1-Wt is reduced by about 1.2% by attaching the stay 5, so it was confirmed that the stay 5 contributed to horsepower reduction.

(Vibration control effect)
FIG. 5 is a front view of the marine duct used to confirm the vibration damping effect of the marine vessel with the marine duct shown in FIG. 1 as viewed from the stern direction.
When the periodic fluctuation frequency of the flow field due to the rotation of the propeller 3 is close to the natural frequency of the cylindrical duct 4, resonance is likely to occur. For example, in the case of the vibration in the primary mode, the vibration is likely to occur at a place (shown by hatching) away from the connection portions 24d and 24b between the hull 2 and the cylindrical duct 4 (see FIG. 5).
When such a resonance phenomenon may occur, a stay 5 that connects the hull 2 and the cylindrical duct 4 is provided in a portion where the vibration is likely to occur, thereby allowing the natural frequency of the cylindrical duct 4 to flow. Can be moved away from the fluctuating frequency of the field. At the same time, the rigidity of the cylindrical duct is improved, and vibration can be avoided.
The number of stays is not limited and is determined by analysis or the like so that the natural frequency of the duct is away from the fluctuation frequency of the flow field. This anti-vibration effect is particularly effective in the case of a duct having a thin cross section.
In addition, the outer shell of the cylindrical duct 4 is illustrated in a side view in which the upper side is longer than the lower side, but the upper side and the lower side may have the same length.

[Embodiment 3: Duct for ships-Part 2]
FIG. 6 is a plan view schematically showing a marine duct according to Embodiment 3 of the present invention. In FIG. 6, the marine duct 60 is installed in place of the marine duct 6 of the marine vessel with a marine duct 1. The marine duct 60 includes a cylindrical duct 40 and a pair of stays 50, and the installation form of the stay 50 on the cylindrical duct 40 is in accordance with the second embodiment (FIG. 2).
The cylindrical duct 40 is a cylindrical body formed from a duct outer plate 43 and a duct inner plate 46.

The duct outer plate 43 is continuous with the stern side outer plate 41 which is a part of a substantially conical shape whose diameter at the bow side is larger than that at the stern side and whose upper side is longer than the lower side, and the bow side edge of the stern side outer plate 41. The bow side outer plate 42 has an inner diameter that gradually decreases toward the bow side edge.
The duct inner plate 46 is continuous with the stern side inner plate 45 which is a part of a cone or a cylinder having a larger diameter on the bow side than the stern side and on the upper side longer than the lower side, and the bow side edge portion of the stern side inner plate 45. And it is formed from the bow side inner board 44 which an internal diameter gradually expands, so that a bow side edge part is approached.
The bow side edge of the bow side outer plate 42 and the bow side edge of the bow side inner plate 44 are continuous.

A stay 50 is connected to the stern side inner plate 45. That is, since the ridge line of the stern side inner plate 45 is a straight line, the side surface 54 of the stay 50 connected to the stern side inner plate 45 is a straight line.
Therefore, the stern side inner plate 45 and the stay 50 can be easily manufactured, and the stern side inner plate 45 and the stay 50 can be easily and easily connected. Therefore, the construction cost of the marine duct 60 is reduced.

  The present invention does not limit the form in which the bow side edge portion of the bow side outer plate 42 and the bow side edge portion of the bow side inner plate 44 are continuous, for example, the bow side edge of the bow side outer plate 42. A pipe body or a rod body is installed between the head portion and the bow side edge portion of the bow side inner plate 44, and the bow side edge portion of the bow side outer plate 42 and the bow side inner plate 44 of the bow side inner plate 44 are installed in the pipe body or rod body. You may make it join a bow side edge part, respectively. At this time, bending processing (three-dimensional bending processing) with a large curvature (small curvature radius) in a range close to the bow side edge of the bow side outer plate 42 and a range close to the bow side edge of the bow side inner plate 44 is performed. Since it can be omitted, the manufacturing cost is low.

  Furthermore, instead of the bow side outer plate 42 whose inner diameter gradually decreases, the entire area of the duct outer plate 43 may be a stern side outer plate 41 formed as a part of a cone (the bow side outer plate 42 may be a stern side outer plate 42). It is the same as assuming that it is formed into a part of a cone continuous with the plate 41). At this time, since the duct outer plate 43 has a linear ridgeline in the entire region, it can be manufactured by simple two-dimensional bending, and the manufacturing cost is reduced. If the installation of the tube or rod is used in combination, the manufacturing cost is further reduced.

[Embodiment 4: Duct for ships-Part 3]
FIG. 7 is a perspective view schematically showing a marine duct according to Embodiment 4 of the present invention. In FIG. 7, a marine duct 8 is obtained by installing a rectifying plate 7 on the upper surface of a stay 5 in the marine duct 6 of the marine vessel with a marine duct 1. Since the rectifying plate 7 is parallel to the hull center plane 2c and promotes the rectifying effect in the cylindrical duct 4, it is in front of the propeller 3 and behind the cylindrical duct 4 (see hatching shown in FIG. 4). The distribution change of the flow field flowing into the vehicle advances, and the effective wake coefficient “1-Wt”, which is one of the self-propelled elements that determine the required horsepower, is further improved. Therefore, the horsepower reduction effect is further improved.

  Since the present invention has the above-described configuration, it can be widely used as an energy-saving device for various ship-shaped ships because it can suppress the manufacturing cost while maintaining the performance as an energy-saving device and prevent the occurrence of vibration. be able to.

The side view etc. which show the outline | summary of the ship with a ship duct concerning Embodiment 1 of this invention. The side view etc. which show the outline | summary of the duct for ships concerning Embodiment 2 of this invention. The perspective view which shows the duct for ships used in order to confirm the energy saving effect of the ship with a duct for ships shown in FIG. The side view for demonstrating the energy-saving effect of the ship with a ship duct shown in FIG. The front view seen from the stern direction which shows the duct for ships used in order to confirm the damping effect of the ship with a duct for ships shown in FIG. The top view which shows typically the duct for ships concerning Embodiment 3 of this invention. The perspective view which shows typically the duct for ships concerning Embodiment 4 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ship with ship 2 Hull 3 Propeller 4 Cylindrical duct 5 Stay 6 Ship duct 7 Current plate 8 Ship duct 9 Skeg 2c Hull center plane 3c Propeller shaft 4c Duct shaft 5c Center plane (stay)
40 cylindrical duct 41 stern side outer plate 42 bow side outer plate 43 duct outer plate 44 bow side inner plate 45 stern side inner plate 46 duct inner plate 50 stay 54 side surface 60 duct for vessel αs elevation angle θd opening angle θs inclination angle Dn stern Side diameter Hs Deviation distance Lb Lower length Ld Upper length

Claims (5)

A marine duct installed at the stern of the hull,
A cylindrical duct skin whose bow side is larger than the stern side;
A cylindrical stern side inner plate connected to the stern side edge of the duct outer plate in a state accommodated in the duct outer plate;
A bow side inner plate that smoothly connects the bow side edge of the duct outer plate and the bow side edge of the stern side inner plate in a state of being accommodated in the duct outer plate;
Have a, a plurality of plate-shaped stays for connecting the stern-side inner plate and the hull,
A marine duct, wherein a rectifying plate parallel to a hull center plane is installed on an upper surface of the stay . The ship duct according to claim 1, wherein the upper side of the duct outer plate is longer than the lower side, and the upper side of the stern side inner plate is longer than the lower side .   The marine duct according to claim 1 or 2, wherein the stern side inner plate is a cylinder or a part of a cone. A pipe or bar is installed along the bow side edge of the duct outer plate,
The ship duct according to any one of claims 1 to 3, wherein a bow side edge of the bow side inner plate is connected to the pipe or bar. The hull,
A propeller installed protruding from the stern of the hull;
The marine duct according to any one of claims 1 to 4, installed at the stern of the hull,
A ship with a duct for a ship.

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