WO2017154539A1

WO2017154539A1 - Ship stern structure

Info

Publication number: WO2017154539A1
Application number: PCT/JP2017/006112
Authority: WO
Inventors: 建剛施; 憲一柴田; 貴偉譚; 将成上原
Original assignee: 常石造船株式会社
Priority date: 2016-03-09
Filing date: 2017-02-20
Publication date: 2017-09-14
Also published as: JPWO2017154539A1

Abstract

Provided is a ship stern structure having a simple configuration which reduces wave-making resistance, the ship stern structure being effective in controlling the orientation of a traveling ship. This ship stern structure comprises: a propeller 1 which is disposed at the stern of a ship; a rudder 5 which is disposed at the rear of the propeller 1; a rudder horn 4 for mounting the rudder 5 to a hull 3; and fins 10 which are mounted on the rudder horn 4 in a manner protruding in the hull width direction. The vertical distance between the rotary shaft of the propeller 1 and the mounting position of the fins 10 is preferably 0.75 R or more, and the length of the fins 10 in the hull width direction is preferably less than 1.0 R, where R is the radius of rotation of the propeller 1.

Description

Ship stern structure

The present invention relates to a stern structure of a ship.

Conventionally, a stern structure has been proposed in which the wave resistance due to stern waves generated near the stern during ship navigation is reduced to improve fuel efficiency. For example, in Patent Document 1, the angle of the lower surface of the wedge provided movably on the stern of the hull is adjusted by a driving device based on the sailing conditions of the hull to reduce the wave-making resistance by the wedge. Inventions relating to ships are described.

Further, Patent Document 2 discloses a spindle provided near the stern bottom at the stern end of the ship, a locking part for rotatably locking the front part of the spindle to the stern bottom, and the spindle in the stern. A spindle-shaped wave suppression unit with a biasing unit that includes a spring that biases from the bottom of the ship, suppresses wave formation from the stern that occurs during medium-to-high speed navigation, and converts the wave energy at the time of wave generation suppression to thrust The invention relating to the structure of the stern portion of the ship is described.

On the other hand, attitude control is also important for reducing drag during ship navigation. As shown in FIG. 10, the attitude of the ship at the time of navigation is changed in attitude (broken line) with respect to the optimum design (solid line) in still water, the bow side (F) sinks and the stern side (R) rises. It becomes a state. Therefore, the resistance on the bow side is increased and the fuel consumption is deteriorated. Therefore, it is preferable to control the posture to approach the optimum design in still water.

JP2015-123904A JP2011-016471A

However, the wave resistance reducing means in the inventions described in Patent Document 1 and Patent Document 2 newly adds a complicated structure to the stern part, and has a problem of cost. In order to reduce the wave resistance, it is necessary to optimize the control of the structure and the shape and angle of the structure. Moreover, according to the invention described in Patent Document 1 and Patent Document 2, there is no effect on attitude control during navigation.

The present invention solves the above-mentioned conventional problems, and provides a stern structure of a ship that reduces wave resistance with a simple configuration and is effective in controlling the attitude during navigation.

In order to solve the above problems, a stern part structure of a ship according to the present invention includes a propeller disposed at a stern part of a ship, a rudder disposed behind the propeller, and a ladder horn for attaching the rudder to a hull. And a fin attached to the ladder horn and projecting in the width direction of the hull.

More preferably, when the rotation radius of the propeller is R, the vertical distance from the rotation axis of the propeller to the attachment position of the fin is 0.75R or more.

Further preferably, when the rotation radius of the propeller is R, the length of the fin in the hull width direction is less than 1.0R. Note that “the length of the fin in the width direction of the hull” refers to the distance from the center in the width direction of the hull to the tip of the fin.

According to the present invention, a propeller disposed at the stern of the ship, a rudder disposed behind the propeller, a ladder horn for attaching the rudder to the hull, and a hull width direction attached to the ladder horn project It has a fin, and the wave-making resistance by the stern wave generated in the vicinity of the stern can be reduced by the fin having a simple configuration. In addition, the fin can generate a downward force on the stern side so that the attitude during navigation approaches the optimum design in still water.

Also, when the propeller turning radius is R and the vertical distance from the propeller rotating shaft to the fin mounting position is 0.75 R or more, wave resistance is reduced and attitude control during navigation For this reason, fins can be provided at appropriate positions.

Also, when the propeller turning radius is R and the fin width direction length is less than 1.0 R, the appropriate length for reducing wave resistance and controlling the attitude during navigation. Fins can be configured.

As described above, according to the present invention, it is possible to provide a stern structure of a ship that can reduce wave resistance with a simple configuration and is effective in controlling the attitude during navigation.

It is a side view which shows the stern part structure of the ship which concerns on embodiment of this invention. FIG. 2 is an AA arrow view of FIG. 1. FIG. 3 is a sectional view taken along line BB in FIG. It is explanatory drawing of the attachment range of a fin. It is explanatory drawing of the length of the hull width direction of a fin. It is explanatory drawing of the length of the hull width direction of a fin. It is explanatory drawing of the length of the hull width direction of a fin. It is explanatory drawing of the angle of the hull front-back direction of a fin. It is explanatory drawing of the angle of the hull front-back direction of a fin. It is explanatory drawing of the attitude | position change at the time of navigation. It is explanatory drawing of downward lift generation | occurrence | production. It is explanatory drawing of the fin size in an Example.

Next, a stern part structure of a ship according to an embodiment of the present invention will be described with reference to FIGS. First, with reference to FIG. 1 thru | or FIG. 3, the basic composition of the stern structure of the ship which concerns on this embodiment is demonstrated. FIG. 1 is a side view showing a stern structure of a ship according to this embodiment. FIG. 2 is an AA arrow view of FIG. 3 is a cross-sectional view taken along the line BB of FIG.

As shown in FIG. 1, a propeller 1 is arranged at the stern part of the ship. The propeller 1 is rotatably attached to the hull 3 via a propeller shaft 2 and is rotated by the power of a main engine disposed in the ship.

A rudder 5 is arranged behind the propeller 1. The rudder 5 is rotatably attached to a ladder horn 4 suspended from the bottom of the hull 3. A valve 6 is provided at a position facing the propeller shaft 2 of the rudder 5.

2 and 3, the ladder horn 4 is provided with fins 10 (10a, 10b) protruding in the hull width direction. The fins 10 (10 a, 10 b) are a pair of left and right symmetrical wing-like members, and protrude toward the left and right sides of the ladder horn 4. In addition, the code | symbol 7 in FIG. 2 has shown the propeller surface of the propeller 1. FIG.

Next, with reference to FIGS. 4 to 9, the fin mounting position, length, and angle in the stern structure of the ship according to this embodiment will be described.

FIG. 4 is an explanatory diagram of the fin mounting range. The attachment position of the fin 10 in the ladder horn 4 is preferably in the attachment range 8 (shaded portion) shown in FIG. The attachment range 8 is a portion in which the vertical distance from the rotation axis C1 of the propeller ₁ to the attachment position of the fin 10 is 0.75R or more when the rotation radius of the propeller 1 is R. At a position below the attachment range 8, the effect of reducing wave resistance and posture control is reduced. Further, as shown in FIG. 1, it is more effective to attach the propeller 1 to a position (1.0 R or more) above the propeller surface 7 because it is less affected by the wake of the propeller. The attachment position of the fin 10 in the ladder horn 4 can be determined as appropriate in accordance with the effects of reduction of wave resistance and posture control.

5 to 7 are explanatory views of the length of the fin in the hull width direction. Here, the "length of the hull width direction of the fins" means the distance from the center C ₂ of the hull width direction to the tip of the fin. The length of the fin in the hull width direction is preferably less than 1.0 R, where R is the rotation radius of the propeller 1. If it is longer than 1.0 R, the resistance of the fin itself is increased, which is difficult in terms of strength. Further, it is preferably 0.5R to 1.0R. This is because if the length is shorter than 0.5R, the effect of reducing wave resistance and posture control is small. However, the length of the fins in the width direction of the hull can be determined as appropriate in accordance with the effects of reduction of wave resistance and attitude control.

Fins 11a, of the hull width direction 11b length shown in FIG. 5 (length from the hull center _{C 2)} _{is L _11,} and has a L 11 = 0.55R. Fins 12a, of the hull width direction 12b length shown in FIG. 6 (the length from the hull center _{C 2)} _{is L _12,} and has a L 12 = 0.74R. Fins 13a, of the hull width direction 13b length shown in FIG. 7 (the length from the hull center _{C 2)} _{is L _13,} and has a L 13 = 0.93R.

8 and 9 are explanatory diagrams of angles of the fins in the longitudinal direction of the hull. The aforementioned fin 10 shown in FIG. 1 is attached so as to be horizontal from the front to the rear of the hull. On the other hand, in the case of the fin 14 shown in FIG. 8, it is attached so as to descend from the front to the rear of the hull, and forms an angle θ ₁₄ (for example, 5 ° to 10 °) with respect to the horizontal. . Further, in the case of the fins 15 shown in FIG. 9, the fins 15 are attached so as to rise from the front to the rear of the hull, and form an angle θ ₁₅ (for example, 5 ° to 10 °) with respect to the horizontal. The angle of the fins in the longitudinal direction of the hull can be determined as appropriate in accordance with the effects of reducing wave resistance and attitude control.

Here, the operational effects of the stern structure of the ship according to the present embodiment will be described. The stern part structure of a ship according to this embodiment is such that fins are provided on the ladder horn 4 and the fins have the following effects.

(Reduction of wave resistance)
Usually, the flow away from the stern end collapses on the surface of the water, leading to an increase in resistance. Therefore, by providing fins in the ladder horn 4, the flow field behind the fins is changed to weaken the momentum of the stern waves, and the flow away from the stern ends is prevented from collapsing. Can be reduced.

(Attitude control)
By providing the fin on the ladder horn 4, a downward lift component can be obtained in the flow from the stern, and the attitude can be controlled. This point will be described with reference to FIG. FIG. 11 is an explanatory diagram of generation of downward lift. In addition, in FIG. 11, it demonstrates taking the case of the fin (fin 15 shown in FIG. 9) attached so that it might raise toward the back from the hull front.

In FIG. 11, the flow V from the stern toward the fin 15 hits the fin 15 slightly from above. Moreover, the cross-sectional shape of the fin 15 is line-symmetric with respect to the center line X in the hull longitudinal direction. At this time, a lift dL is generated in the fin 15 and is decomposed into a forward component and a downward component. Therefore, a downward force is generated on the stern side by the downward lift component with respect to the fin 15, and the attitude during navigation can be controlled so as to approach the optimum design in still water.

Generally, lift occurs in a direction perpendicular to the flow, and the direction of lift is the blade suction surface. The magnitude of the lift varies with the pressure difference between the front surface (upper surface) and the back surface (lower surface), and when the pressure difference is zero, the lift is also zero. Here, the approach direction of the flow from the stern to the fin differs depending on the stern shape. Accordingly, a fin (fin 10 shown in FIG. 1) attached so as to be horizontal from the front to the rear of the hull, or a fin (shown in FIG. 8) attached so that the fin descends from the front of the hull to the rear. Even with the fins 14), a downward lift force can be generated depending on the direction of the flow from the stern to the fins. Moreover, downward lift can also be generated by making the cross-sectional shape of the fins asymmetric.

According to the stern part structure of the ship according to the present embodiment, the propeller 1 disposed at the stern part of the ship, the rudder 5 disposed behind the propeller 1, and the ladder horn 4 for attaching the rudder 5 to the hull 3. And the fin 10 which protrudes in the hull width direction attached to the ladder horn 4, and can reduce the wave-making resistance by the stern wave which generate | occur | produces in the stern vicinity with the fin 10 of a simple structure. Further, a downward force can be generated on the stern side by the fin 10 so that the attitude during navigation can be controlled so as to approach the optimum design in still water.

Moreover, the radius of rotation of the propeller 1 is taken as R, in the case where the vertical distance from the axis of rotation C ₁ of the propeller 1 to the attachment position of the fin 10 and the above 0.75R includes a reduction of the wave resistance The fin 10 can be provided at an appropriate position for posture control during navigation.

Also, when the propeller turning radius is R and the fin width direction length is less than 1.0 R, the appropriate length for reducing wave resistance and controlling the attitude during navigation. The fins 10 can be configured.

As mentioned above, according to the stern part structure of the ship which concerns on this embodiment, while reducing wave-making resistance with a simple structure, the attitude | position at the time of navigation can be controlled effectively.

Next, the CFD simulation result regarding the resistance reduction effect by the stern part structure of the ship according to the present embodiment will be described. The conditions for the CFD simulation are as follows.

(Fin size)
FIG. 12 is an explanatory diagram of the fin size in the embodiment, where the blade width L = 2000 mm, the root cord length Cr = 1070 mm, and the tip cord length 500 mm. Incidentally, wingspan L is the length of the hull center C _2. The propeller rotation radius R = 2700 mm, and the length of the fin in the hull width direction (wing width L) is 2000 / 2700≈0.74R. Further, the vertical distance from the axis of rotation _{C 1} of the propeller to the mounting position of the fin is 3050 mm, which is 3050/2700 ≒ 1.13R.

(Calculation model and calculation conditions)
Resistance calculation by free surface model and self-propulsion calculation by double model were performed. As calculation conditions, the Froude number Fn = 0.25. Table 1 shows the results of the CFD simulation by the reduction rate of the main machine horsepower BHP based on the comparative example (without fins).

As shown in Table 1, the resistance reduction effect by the fins was confirmed. This resistance reduction effect is considered to be an effect of both the reduction of wave resistance and the control of the attitude during navigation.

As mentioned above, although the stern part structure of the ship which concerns on embodiment of this invention was demonstrated, this invention is not necessarily limited to embodiment mentioned above, Other various changes are possible. For example, in the above-described embodiment, the fin 10 is a pair of left and right

symmetrical fins

10a and 10b. However, the mounting positions, lengths, and angles of the left and right fins may be asymmetrical.

DESCRIPTION OF SYMBOLS 1 Propeller 2 Propeller shaft 3 Hull 4 Ladder horn 5 Rudder 6 Valve 7 Propeller surface 8 Mounting range 10 Fin 11 Fin 12 Fin 13 Fin 14 Fin 15 Fin

Claims

A propeller disposed at the stern portion of the ship; a rudder disposed behind the propeller; a ladder horn for attaching the rudder to a hull; and a fin projecting in a width direction of the hull attached to the ladder horn. A stern structure of a ship, characterized by comprising:
2. The stern of a ship according to claim 1, wherein when the rotation radius of the propeller is R, a vertical distance from a rotation axis of the propeller to a mounting position of the fin is 0.75 R or more. Part structure.
The ship stern structure according to claim 1, wherein the length of the fin in the hull width direction is less than 1.0R, where R is the rotation radius of the propeller.