JP2002178993A - Rudder for ship - Google Patents

Abstract

PROBLEM TO BE SOLVED: To recover the kinetic energy of a vortex flow at the end of propeller blade as thrust. SOLUTION: The rudder for ship is configured with a rudder plate, a rudder shaft and a bearing structure protruding from the stern shell downward till near the center of the rudder plate, wherein the rudder plate is borne rotatably by the shaft and bearing structure, and fins 4a and 4b for recovering the vortex energy at the end of propeller blade overhung to both ship sides are installed in positions approximately at a level with the top H and bottom L of the propeller 3 located ahead of the rudder plate 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boat rudder, and more particularly to a boat rudder capable of recovering, as thrust, kinetic energy of a vortex flow generated from a wing tip of a boat propeller.

[0002]

2. Description of the Related Art A rudder provided with fins on a rudder plate for recovering energy of a flow generated by rotation of a propeller (a wake behind the propeller) has been proposed for the purpose of improving the propulsion performance of a ship. . As a conventional technique related to a ship rudder provided with such fins, Japanese Utility Model Publication No.
No. 18, JP-A-4-201693 and JP-A-47-15895.

FIG. 4 is a view showing the shape of a fin (conventional example 1) disposed on a rudder disclosed in Japanese Utility Model Publication No. 6-35918, where (a) is a side view of the rudder and (b) is a side view of the rudder. It is a front view of a rudder. The fins 22a and 22b attached to the rudder 21 of the ship project from the rudder 21 symmetrically on both sides with respect to the rudder center line 23 in a vertical range of 10% of the propeller diameter from the height of the propeller axis Pc. Attached
The leading edge of the rudder 21 and the leading edge of the fins 22a and 22b are made to coincide with each other, or the leading edge of the fins 22a and 22b is arranged at a distance within 5% of the propeller diameter from the leading edge of the rudder 21. The edge has a sweepback angle of not less than 20 degrees and not more than 50 degrees, and the chord length at the junction with the rudder 21 in the planar shape of the fins 22a and 22b is 1.5 times the chord length at the outer ends of the fin fins 22a and 22b. The fins 22a on the starboard side and the fins 22b on the port side have cambers that are up and down in length with respect to the noise tail line.

FIG. 5 is a view showing a boat rudder (prior art 2) disclosed in Japanese Patent Application Laid-Open No. 4-201693.
(A) is a plan view, (b) is a front view, (c) is a right side view,
(D) is a left side view.

This rudder for boats has fins extending laterally from both sides of the rudder of the boat. At the front edge of the rudder 31, the stern 33 is located at the position where the fins 32a and 32b are attached.
The propeller 34 is provided with a protruding portion 36 (bulb) protruding forward so as to be close to the propeller boss cap 35.

FIG. 6 is a view showing a rudder (conventional example 3) disclosed in JP-A-47-15895, wherein (a) is a perspective view of the rudder viewed from an oblique side, and (b) is a front view of the rudder. FIG. 1C is a side view of the rudder, and FIG. 2D is a perspective view of the rudder viewed from obliquely forward.

This rudder is provided with fins 43a and 43a on both sides near the center in the vertical direction of a rudder 42 disposed behind the screw propeller 41.
b) and the fin 43 on the side where the propeller blades 41 rise with the rotation of the screw propeller 41.
a has a positive angle of attack and its propeller wings 41
The fin 43b on the side where the angle of descent falls has a negative angle of attack.

A rudder in which fins are provided at a position different from the height at which the propeller shaft is located is disclosed in Japanese Patent Laid-Open No. 9-263.
There is a rudder disclosed in Japanese Patent Publication No. 299 (conventional example 4). This rudder is a rudder 53 of a boat provided behind a propeller shaft 52a of a propeller 52 provided at the stern of a hull 51, as shown in the side view of FIG.
Fins 55 and 56 are attached to the inflow side position of the flow in the rotation direction by the propeller 52.

In the prior arts 1-4, at the fins or fins provided on the rudder, the energy behind the propeller is recovered as lift, and the component of the lift in the traveling direction of the ship is converted into thrust.
It contributes to the improvement of the thrust of the ship, and has the effect of saving energy and improving fuel efficiency as a whole.

[0010]

However, the above-mentioned conventional rudder for ships having fins or fins has the following problems.

[0011] The propeller wake includes a propeller hub vortex generated by rotation of the propeller hub, a propeller tip vortex generated from the propeller blade tip, and a flow generated by these vortices.

The above-mentioned conventional fin or fin (hereinafter referred to as "fin" or "fin")
Conventional example 1 of a ship rudder having a fin
In the rudder of Conventional Example 3, the fin is provided near the propeller shaft center height of the rudder, and the energy of the rotational flow induced by the propeller hub vortex in the wake of the propeller will be recovered by the fin provided on the rudder. The kinetic energy of the flow of the propeller tip vortex cannot be recovered.

In the rudder of Conventional Example 4, the fins are provided at positions other than the height of the propeller shaft center, and the fins are provided at the inflow side of the flow in the rotational direction by the propeller.
It cannot be said that the fin is arranged at a position where the energy of the flow of the propeller tip vortex can be reliably recovered.

Therefore, in each of the prior arts, the kinetic energy of the vortex flow generated from the tip of the marine propeller is described.
Are not recovered and used as thrust.

The present invention has been made to solve the above-described problems of the prior art, and can recover kinetic energy of a vortex generated from a wing tip of a marine propeller as a thrust. It aims to provide a ship rudder.

[0016]

A first marine rudder according to the present invention has a fin for recovering vortex energy at the tip of a propeller blade at a position substantially at the same height as the upper and lower ends of the propeller. It is a thing.

The position of the fin for recovering the vortex energy from the propeller blade tip to the rudder plate is set at a position 10% above the propeller diameter with respect to the upper and lower ends of the propeller. The range is up to a height of 10% below the length.

In the rudder for a boat according to the present invention, fins for recovering the vortex energy of the propeller tip are provided at positions of the rudder plate opposite to the upper end and the lower end of the propeller, and the flow generated by the flow of the vortex of the propeller tip is provided. Energy can be efficiently recovered.

Further, a second marine rudder according to the present invention comprises:
At the height position corresponding to the height of the propeller shaft, fins extending laterally from both sides of the rudder plate are provided, and at the leading edge of the rudder, at the fin mounting position, close to the propeller boss cap of the stern propeller. A marine rudder provided with a protruding portion protruding forward and attached with the above-mentioned propeller blade tip vortex energy recovery fin.

By using this boat rudder, in addition to the energy of the propeller hub vortex generated by the rotation of the propeller hub, the energy of the vortex flow generated at the propeller blade tip can be recovered. Propulsion efficiency can be improved.

The propeller impeller vortex is described in “Propeller Wake Visualization by Air Bubbles, Ichiro Tanaka et al., 8th Symposium on Flow Visualization, 1980”. It is explained based on. 3A and 3B are views of the stern direction and the port side, and FIG. 3A is a view of the port side propeller tip vortex, FIG. 3B is a view of the port side propeller tip vortex viewed from the stern, and FIG. FIG. 3 is a diagram of a starboard-side propeller tip vortex, and FIG. 3D is a diagram of the starboard-side propeller tip vortex as viewed from the stern. Although not shown, the propeller is located to the left of the rudder 102 and rotates clockwise as viewed from the stern direction. FIG.
As shown in (a) and (c), the vortex (propeller tip vortex) 101 generated from the propeller tip forms a spiral trajectory as the ship progresses, and is divided into two parts by the front surface of the rudder 102. Is regarded as a semi-arc having a certain inclination with respect to the horizontal straight traveling direction (propeller axis X direction) on the rudder 102 surface.

This inclination angle is reversed on the left and right surfaces of the rudder 102, and as shown from the stern of FIGS. 3 (b) and 3 (d), by considering the rudder 102 surface as a mirror image surface, a continuous circular vortex is formed. Becomes 3 (a) and 3 (b), the solid line indicates the semicircular vortex 103 of the propeller tip vortex on the port side, and the dashed line indicates the mirror image 104 thereof. 3 (c) and 3 (d), a broken line indicates a semicircular vortex 105 of a propeller tip vortex on the starboard side.
, And the dashed line indicates its mirror image 106.

Since the left and right circular vortex streets move in the direction of the inclined central axis, the port side rises as shown in FIG.
The starboard side descends as shown in FIG. As a result, an upward flow occurs on the port side of the rudder 102, and a downward flow occurs on the starboard side of the rudder 102. Fins for recovering the energy of the upward flow and the downward flow generated by the flow of the propeller tip vortex as lift are provided at the rudder position where the upward flow and the downward flow occur, and the component of the lift in the traveling direction component of the ship is provided. Is recovered as thrust to improve the propulsion performance of the ship.

[0024]

Embodiments of the present invention will be described with reference to the drawings. 1A and 1B are explanatory diagrams of a boat rudder according to the present invention. FIG. 1A is a side view of the boat rudder, FIG. 1B is a plan view of the boat rudder, and FIG. 1C is a front view of the boat rudder from the stern side. FIG. This is when the propeller rotates clockwise as viewed from the stern direction. The ship rudder 1 has a propeller blade tip vortex energy recovery at a height position substantially corresponding to the upper wing tip height H and the lower wing tip height L of the propeller 3 disposed at the stern of the hull 2. Fins 4a and 4b are provided.

In the vicinity of the upper blade tip height of the propeller on the port control surface, an upward flow is generated by the flow of the propeller tip vortex, and conversely, the downward flow is generated near the lower blade height of the propeller on the starboard surface. As shown in FIG. 1 (a), the camber projecting upward near the upper wing tip height of the propeller on the port control surface.
A fin 4a having a 5a is provided to recover lift from an upward flow, and a fin 4b having a camber 5b projecting downward is provided near a wing tip height of a propeller on a starboard control surface to recover lift from a downward flow. I do.

Then, the component in the traveling direction of the ship out of the lift is recovered as thrust, and the propulsion performance of the ship is improved.

Further, a detailed description will be given of the fin mounting range.
The range in which a is attached is 10% of the diameter of the propeller 3 above and below the upper wing tip height H. The range in which the propeller blade tip vortex energy recovery fin 4b on the lower end side is attached is above and below the propeller 3 by 10% of the diameter of the propeller 3 around the lower blade tip height L.

The position of the fin for recovering the vortex energy from the tip of the propeller is set on the rudder plate from the height of 10% of the diameter of the propeller with respect to the upper and lower ends of the propeller, from the height of 10% of the diameter of the propeller. The range up to the height below is set to be approximately the range where the upward flow and the downward flow caused by the flow of the propeller tip vortex are generated by experiments on observation of the flow on the rudder surface by a model ship in a self-propelled state. This is because it was confirmed that it was limited to

It should be noted that the vortex energy of the tip of the propeller blade at the upper end is
The collection fin 4a is provided on the rudder 1 itself,
May be arranged on the ladder horn 6 to which the horn is attached.

In FIG. 1, only one fin 4a and 4b for recovering the vortex energy of the propeller blade tip are provided, but one fin may be provided on the opposite side. This is because the propeller tip vortex bisected at the rudder leading edge draws a semicircular trajectory with the port side upward and the starboard side downward with respect to the propeller axis, but the rudder surface is defined as the mirror image surface. By thinking, it can be considered as a continuation of circular vortices, and theoretically, an upward flow occurs near the starboard-side upper propeller tip height as well as on the port side, and the port-side lower propeller tip This is because it is considered that a descending flow is also generated near the height as in the starboard side. Thereby, the propulsion performance of the ship can be further improved.

Further, it is preferable that the position in the front-rear direction where the propeller blade tip vortex energy recovery fin is mounted is near the rudder leading edge, because the flow generated by the propeller blade vortex can be effectively used.

The code length of the propeller blade tip vortex energy recovery fin is at most equal to or less than the rudder code length.

FIG. 2 shows another embodiment of the boat rudder of the present invention. This rudder for boats has a propeller blade tip vortex energy at a height position corresponding to the height of the propeller shaft 11 to collect the energy of the flow of the vortex flow of the propeller hub having the fins 12a, 12b and the valve 13 attached thereto. It is provided with recovery fins 4a and 4b.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A tank test was conducted on a model ship of an oil tanker having a rudder 14 as shown in the perspective view of FIG. 2 and a model ship having a rudder without a propeller blade tip vortex energy recovery fin. It was examined how the propulsion performance was changed by attaching the eddy energy recovery fins 4a and 4b.

Table 1 shows the results.

[0036]

[Table 1]

The required shaft horsepower (BHP) of the ship is obtained from the effective horsepower (EHP) by the following equation (1).

BHP = EHP / (η _P × η _T ) = EHP / (η _H × η _O × η _R × η _T ) (1) where η _P (= η _H × η _O × η _R ): Propulsion efficiency η _H ｛= (1-t) / (1-w)｝: Hull efficiency η _O : Propeller independent efficiency η _R : Propeller efficiency ratio η _T : Transmission efficiency (for engine horsepower and propeller It is the ratio to the transmitted horsepower,
T: Thrust reduction coefficient w: Wake coefficient When the reduction rate of shaft horsepower is calculated from η _R , t, w obtained from the results of the tank test, the reduction rate is 1.2%, and the propeller blades It was confirmed that the propulsion performance was improved by providing the end vortex energy recovery fins.

[0039]

According to the present invention, the vortex energy of the propeller blade tip can be recovered, so that the propulsion efficiency of the ship can be improved.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory view of a boat rudder of the present invention, wherein (a) is a side view of the boat rudder, (b) is a plan view of the boat rudder, and (c) is a front side of the boat rudder on the stern side. FIG.

FIG. 2 is a perspective view of a boat rudder according to another embodiment of the present invention.

FIG. 3 is a diagram showing the flow of a propeller tip vortex, and FIG.
(B) is a view of the propeller tip vortex on the port side seen from the stern, (c) is a view of the propeller tip vortex on the starboard side, and (d) is a view of the propeller tip vortex on the starboard side. It is the figure which looked at the propeller wing tip vortex from the stern.

4A and 4B are explanatory diagrams of a rudder for a boat according to Conventional Example 1, wherein FIG. 4A is a side view of the rudder, and FIG. 4B is a front view of the rudder.

5 (a) is a plan view, FIG. 5 (b) is a front view, FIG. 5 (c) is a right side view, and FIG. 5 (d) is a left side view.

6A and 6B are explanatory views of a rudder for a boat according to Conventional Example 3, in which a) is a perspective view of the rudder viewed from an oblique side, FIG. 6B is a front view of the rudder, and FIG.
Is a side view of the rudder, and (d) is a perspective view of the rudder viewed from diagonally forward.

FIG. 7 is a side view of a boat rudder of Conventional Example 4.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rudder for ship 2 Hull 3 Propeller 4a, 4b Fin for recovering vortex energy from propeller blade tip 5a Camber projecting upward 5b Camber projecting downward 6 Ladder horn 11 Propeller shafts 12a, 12b Fin 13 Valve 14 Rudder

Claims (3)

[Claims] 1. A rudder for a ship, wherein a fin for recovering vortex energy from propeller blade tips is provided at a position substantially at the same height as the upper and lower ends of the propeller. 2. The mounting position of the propeller blade tip vortex energy recovery fin on the rudder plate is set at 10% of the propeller diameter with respect to the upper and lower ends of the propeller, respectively, from the height of the propeller diameter. 2. The marine rudder according to claim 1, wherein the range is up to a height below 10% of the length. 3. A fin that extends laterally from both sides of the rudder plate at a height corresponding to the height of the propeller shaft, and a propeller boss of a stern propeller is provided at a position where the fin is mounted at a leading edge of the rudder. The boat rudder according to claim 1 or 2, further comprising a protrusion protruding forward so as to approach the cap.