JPH1159588A - Bilge vortex energy recovery device for ship - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently convert the kinematic energy of the bilge vortex to be induced by the navigation of a hull into the propulsion of the hull. SOLUTION: In a vortex energy recovery device, each main fin 8 is mounted on the surface of a hull 1 on the port and starboard sides forward of a propeller 6, in each main fin 8, its root part 8b is on the hull surface, and a fin end part 8c is located approximately at the center 4 of the bilge vortex, and has a downward camber. An auxiliary fin 9 with the camber in the direction to cancel the rotational flow by the bilge vortex is mounted on the fin end part 8c of the main fin 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bilge vortex energy recovery system for a marine vessel mounted on a stern hull surface in front of a propeller to achieve a reduction in hull resistance and an improvement in propulsion efficiency.

[0002]

2. Description of the Related Art In a marine vessel, as shown in FIG. 7 (a perspective view from the bottom of the hull), near an aft end of a bilge 1a on both sides of a stern 1 'of a hull 1, an upward flow 2 wrapping upward from a bottom 1b. And the descending flow 3 which is going to flow inward from the ship side, intersects, and a bilge vortex 5 having a bilge vortex center 4 having this portion as a generation source is generated. The bilge vortex also forms a bilge vortex 5 'on the starboard side, which is opposite to the port side. In particular, in the case of an enlarged ship, the bilge vortices 5, 5 'cause large-scale three-dimensional separation on the surface of the hull in front of the propeller 6, causing a large increase in the resistance of the ship.

[0003] The bilge vortices 5, 5 'induce a flow that rotates in opposite directions on the port and starboard sides as viewed from the stern, flow to the propeller position while developing, and flow off to the rear of the ship.

The bilge vortex 5 is a downward flow obliquely downward on the hull side of the bilge vortex center 4 and is an upward flow obliquely upward outside the bilge vortex center 4. The flow around the bilge vortex center 4 is a rotational flow, and the energy that induces this rotational speed is given to the fluid by the vessel moving in the fluid against the resistance, and the resistance of the vessel increases. It is causing.

Conventionally, the present inventor of the present invention has improved the propulsion performance of a ship by elucidating the vortex phenomenon described above.
No. 6693, “Billge Vortex Energy Recovery Apparatus for Ships” is known.

In the above invention, one fin is mounted on each of the hull surfaces on the left and right sides in front of the propeller. The fins have their wing roots on the hull surface and their wing tips are located substantially at the center of the bilge vortex. , A bilge vortex energy recovery device for a marine vessel having a downward camber.

[0007]

However, in the above-mentioned invention, it is possible to recover a part of the kinetic energy given to the fluid by the generation of the bilge vortex, but the space region from the center of the bilge vortex to the surface of the hull is small. Since the fins occupy the space area cannot be formed to be large because of the small size, the wing surface load of the fins becomes too large, and the flow separation on the back surface of the fins may occur, and the kinetic energy of the bilge vortex is effectively recovered. It was difficult. Therefore, it is necessary to increase the area of the fins by some means to reduce the load on the blade surface and to increase the energy recovery efficiency.

[0008] In addition, the above publication discloses a wing tip plate and a winglet attached to a fin tip, and the wingtip plate and the winglet are designed to lift the fin body. It does not attempt to primarily recover the kinetic energy of the rotating bilge vortex flow that the stern flow has.

According to the present invention, the wing surface load of the entire fin is appropriately maintained, and the energy of the rotating flow caused by the bilge vortex accompanying the three-dimensional separation of the stern is more effectively converted into thrust, thereby reducing the resistance of the hull. The purpose is to increase the propulsion efficiency.

[0010]

SUMMARY OF THE INVENTION The above-mentioned problem is that one wing is mounted on the hull surface in front of the propeller on each of the left and right sides, the wing roots are on the hull surface, and the wing tips are substantially in the center of the bilge vortex. A marine vessel comprising: a main fin having a camber that is positioned and facing downward; and an auxiliary fin that has a camber in a direction to cancel the rotational flow due to the bilge vortex and is attached to a wing tip of the main fin. The bilge vortex energy recovery system solves this.

According to the above-mentioned means, in a bilge vortex energy recovery system for a ship in which a pair of main fins are disposed on the hull surfaces on both sides in front of the propeller at the stern, a bilge vortex is provided at the wing end of the main fin. Auxiliary fins with cambers are installed in the direction to cancel the rotational flow caused by the fins, increasing the area of the fins and reducing the wing surface load on the entire fins, thereby separating the wing surface flow on the back surface (lower surface) of the main fins And the kinetic energy of the bilge vortex is more effectively recovered as thrust to reduce the resistance of the hull, improve the propulsion efficiency of the ship, and increase the energy saving effect of the ship.

Further, the number and area of the auxiliary fins are set according to the strength of the bilge vortex which changes according to the hull form.

The camber of the main fin is downwardly convex with respect to the center of the bilge vortex, but the auxiliary fin has a camber convex on the same side as the main fin when viewed in the direction of rotation of the vortex with respect to the center of the bilge vortex. Have. By providing such auxiliary fins, the kinetic energy of the bilge vortex that could not be recovered only by the main fins can be recovered by the auxiliary fins.

[0014]

FIG. 1 is a side view of a bilge vortex energy recovery apparatus for a marine vessel according to the present invention when applied to a uniaxial ship having a single propulsion shaft.

In FIG. 1, 1 is a hull, 6 is a propeller,
7 is a rudder. 8 is a main fin, and the camber 8 is directed downward.
a and a predetermined angle of attack is set, and the wing root is attached to the hull 1.

Reference numerals 9 and 9 'denote auxiliary fins attached to the wing tip outside the main fin 8.

Reference numeral 10 denotes a rectifying valve for preventing separation of water flow at a portion where the main fin 8 and the auxiliary fins 9 and 9 'are attached, and is provided as necessary. The number of auxiliary fins 9 and 9 'and the wing area increase or decrease depending on the strength of the bilge vortex generated by the hull form.

FIG. 2 is a sectional view taken in the direction of the arrow A in FIG. 1 (the rudder 7 is omitted). The main fin 8 has a wing root 8b attached to the hull 1 and an auxiliary fin 8 attached to a wing tip 8c via a rectifying valve 10. 9
Is installed. The starboard side is not shown.

FIG. 3 is a front view showing the bow direction from the stern. The position of the rectifying valve 10 where the auxiliary fins 9 and 9 'and the main fin 8 are attached is preferably near the rotation center of the bilge vortex.

FIGS. 4, 5 and 6 illustrate the principle of obtaining the thrust according to the present invention. FIG. 4 is a view taken in the direction of arrow A in FIG.
3 is a view as seen from the arrow B in FIG. 3, and FIG. 6 is a view as seen from the arrow C in FIG.

In FIG. 4, the main fin 8 is formed by a convex wing surface on the lower side, has a camber 8d, and is set at an appropriate angle of attack with respect to the downward flow induced by the bilge vortex.

V ₁ is a velocity vector flowing into the main fin 8 of the flow induced by the bilge vortex, and is composed of a horizontal backward velocity component vector V _a1 and a vertical velocity component vector V _T1 . The main fin 8 lifts L ₁ by the flow described above.
Is generated, and the vertical direction vector component L _V1 and the horizontal direction force vector component L _h1 become the thrust for moving the hull 1 forward.

In FIG. 5, the auxiliary fin 9 is formed with a convex wing surface on the hull 1 side, has a camber 9a, and is suitable for an inward (toward the hull side) flow induced by a bilge vortex. Angle of attack is set. V ₂ is a velocity vector flowing into the auxiliary fins 9 of the flow induced by the bilge vortex, and is composed of a horizontal backward velocity component vector V _a2 and a horizontal velocity component vector V _T2 perpendicular to the hull direction. .

The auxiliary fins 9 generate a lift L
₂ , which are generated by a horizontal force vector component L _l2 toward the hull and a horizontal forward force vector component L _h2.
And can be separated into The horizontal force vector component L _h2 is a thrust for moving the hull 1 forward.

In FIG. 6, the auxiliary fin 9 'is formed with a convex wing surface on the outside of the hull 1 and has a camber 9'a, and the outward (away from the hull) flow induced by the bilge vortex. Is set to an appropriate angle of attack. V
₃ is the auxiliary fin 9 'of the flow induced by the bilge vortex
The velocity vector V _a3 is a velocity vector that flows horizontally backward, and is composed of a velocity component vector V _{T3 in the} horizontal direction that extends perpendicularly to the outside of the hull. Auxiliary fin 9
Can is to generate lift L ₃ by the flow, which is to be separated into a force vector component L _h3 and horizontal force vector component L _l3 horizontal forward facing towards the hull outside.
The horizontal force vector component L _h3 is a thrust for moving the hull 1 forward. Incidentally, 6a indicates propeller boss.

[0026]

As described above, according to the present invention, since the auxiliary fin is attached to the wing tip of the main fin, the rotational energy of the bilge vortex is almost completely converted to the propulsion energy and recovered. .

Further, since the flow flowing into the propeller is decelerated by the main fin and the auxiliary fin, there is an effect of increasing the propulsion efficiency of the ship.

[Brief description of the drawings]

FIG. 1 is a side view of a bilge vortex energy recovery device for a ship according to the present invention.

FIG. 2 is a plan sectional view taken along the arrow A of FIG. 1;

FIG. 3 is a cross-sectional view of the present invention as viewed in the bow direction from the rear of the hull, and shows the port side.

FIG. 4 is a view taken in the direction of arrow A in FIG. 3;

FIG. 5 is a view taken in the direction of the arrow B in FIG. 3;

FIG. 6 is a view as viewed in the direction of arrow C in FIG. 3;

FIG. 7 is a perspective view showing the generation state of a bilge vortex as viewed from the bottom of the ship.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hull 1a Bilge part 1b Ship bottom 2 Upflow 3 Downflow 4 Center of bilge vortex 5 Bilge vortex 5'Bilge vortex 6 Propeller 7 Rudder 8 Main fin 8a Camber 8b Wing root part 8c Wing tip part 8d Camber line 9 Auxiliary fin 9 'auxiliary Fins 9a Camber line of auxiliary fins 9'a Camber line of auxiliary fins

Claims (1)

[Claims] 1. A wing root is located on the surface of the hull, a wing tip is located substantially at the center of the bilge vortex, and has a downward camber. A bilge vortex energy recovery device for a ship, comprising: a main fin; and an auxiliary fin having a camber in a direction to cancel a rotational flow caused by the bilge vortex, and attached to a wing tip of the main fin.