KR101106708B1 - Ship rudder operating its upper and lower parts separately and having rudder bulb - Google Patents

Abstract

The present invention relates to a rudder for ships that can reduce lift loss and reduce cavitation occurring on the surface. More specifically, the present invention relates to a steering gear room connected to a rotating shaft and a rudder at the lower end. It consists of an upper rudder having a bulb and a lower rudder having a rudder bulb connected to a shoe piece and having a rotary shaft. The upper rudder and the lower rudder are completely separated at regular intervals. The present invention relates to a separate rudder of a ship having a rudder bulb, which is rotated individually at each rudder angle in a state.

Description

Ship rudder operating its upper and lower parts separately and having rudder bulb

The present invention relates to a ship rudder capable of reducing lift loss and reducing cavitation occurring at the surface.

Rudder, which determines the ship's maneuverability, has received relatively limited attention compared to propellers that generate propulsion. The rudder, located downstream of the rotating propeller, operates in a wake field downstream of the propeller, which is highly non-uniform in three dimensions. However, in recent years, due to the large size and high speed of the ship, the hydrodynamic load on the propeller and the rudder has been greatly increased, so that the rudder directly affected by the propeller wake characteristics, as well as the performance characteristics causing the lift and drag generation, There is also a lot of interest in cavitation.

1 is a view of the propeller 2 and the existing rudder 1 installed on the stern of the ship. Since the sign of the direction of the flow flowing in the upper and lower direction of the rudder installed downstream of the rotating propeller and the angle of attack are opposite to each other as shown in FIG. 2, a positive or negative force (lift) is generated for each cross-sectional position of the rudder. Offsets a large amount of lift.

Therefore, excessive rudder angle setting is necessary to secure necessary lift. However, the increase in the rudder angle causes the erosion of the other surface by increasing the amount of cavitation generated on the other surface. And the botex cavitation generated in the propeller hub collapses on the other surface, causing erosion. Although many research institutes and shipyards have a lot of interest and effort to reduce lift loss and cavitation incidence in horn rudder (semi-spade rudder) (Fig. 3) or full-spade rudder (Fig. 5). It is, but the effectiveness is limited.

Many ship owners, in particular, prefer the use of horn-taches consisting of fixed and movable parts due to the traditional customs of ships. There is a limitation in overcoming the problem of the loss of, and the problem of serious gap cavitation accompanied by erosion in the gap clearance in the vertical and horizontal directions is also seriously raised.

Although the preference for full-motion rudders is gradually increasing to overcome this gap cavitation, there is a limit in reducing the cavitation appearing on the other surface due to the increased rudder angle to overcome the lift loss as described above. And full spade rudders are accompanied by an increase in the steering angle to secure the required inertia, which is very limited in improving the steering (lift) performance such as the ship's turning performance.

The present invention has been proposed to solve the above problems, to reduce the lift loss of the rudder to improve the steering performance of the vessel, to reduce the drag energy to reduce the operating energy of the vessel, to reduce the cavitation generated on the rudder surface It aims to provide rudders for ships that can minimize damage caused by propeller hub votex cavitation as well as reduce other surface erosion.

Other objects and advantages of the present invention will be described below, which are not limited to the matters set forth in the claims and the disclosure of the embodiments thereof, but also to the broader ranges by means and combinations within the range readily recited therefrom. Add that it will be included.

In order to achieve the above object, the present invention is connected to the steering gear room by a rotating shaft and the lower end of the upper rudder having a rudder bulb, connected to the shoe piece by a rotating shaft and having a rudder bulb at the upper end It consists of a lower rudder, wherein the upper rudder and the lower rudder are rotated individually at each rudder angle in a completely separated state at regular intervals, proposes a separate rudder of a ship having a rudder bulb.

According to the present invention, since the angle of attack of each of the upper and lower rudders can be set, lift lift does not occur unlike the conventional integrated rudder. In addition, even if the angle of attack is reduced, the necessary inertia (lift) can be secured, which reduces the amount of cavitation generated on the rudder surface and reduces the possibility of surface erosion. And the ship's operation at a smaller angle of attack causes the drag of the rudder to be reduced, thus reducing the ship's operating energy. In addition, since the canceling phenomenon of the existing integral rudder is eliminated, the turning circle of the ship can be reduced and the steering performance can be improved. In addition, the rudder surface erosion caused by propeller hub vortex cavitation is avoided by being separated into upper rudder and lower rudder in shape. Other bulbs increase the hull wake by reducing the stern constriction. Therefore, the hull efficiency (ηH = (1-t) / (1-w), t: thrust reduction factor, w: wake) is increased to contribute to increase the propulsion efficiency of the ship. This effect is expected to have a positive effect on the development of the domestic shipbuilding industry in connection with the life extension of the rudder, the propulsion efficiency and the maneuverability of the ship.

Other effects of the present invention, as well as those described in the above-described embodiments and claims of the present invention, as well as potential effects that may occur within the range that can be easily estimated therefrom and potential advantages that contribute to industrial development It will be added that it will be covered by a wider scope.

1 is a general propeller and rudder attached to the stern of the ship.
2 is a propeller wake and rudder.
3 is the shape of a typical horn-ta.
4 is a cross-sectional view of the upper and lower fins of a typical horn-ta;
5 is a shape of a general fully movable rudder.
Figure 6 is a cross-sectional shape of a general full swing.
Figure 7 is a propeller and a split rudder in accordance with the present invention.
8 is an arrangement of the propeller inflow and the split rudder according to the present invention during the straight operation of the vessel.
Figure 9 is a layout of the propeller inflow and the split rudder according to the present invention during the starboard turn of the ship.
Figure 10 is a layout of the propeller inflow and the split rudder according to the present invention when turning the port of the ship.
11 is an incident angle distribution of the rudder of the propeller wake obtained in the model test when the stern reflux exists.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible, even if shown on different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, the following will describe a preferred embodiment of the present invention, but the technical idea of the present invention is not limited thereto and may be variously modified and modified by those skilled in the art.

The ship's propeller normally gains momentum by turning clockwise when looking at the stern. Due to the directionality of the propeller rotation, the propeller wake flows into the rudder located behind the propeller with a constant angle of attack, as shown in FIG. 2, above the port port and the starboard. Due to the characteristics of the propeller wake, even if the ship's rudder angle is 0 degrees, the lift force that directly affects the maneuverability of the ship is different from '0', which prevents the ship from operating in a straight line. In addition, when the ship's steering angle is adjusted to the port or starboard, a large angle of attack may appear on the upper or lower portion of the rudder, causing lift loss.

11 shows the results of a model test in a cavitation tunnel for a general horn-hit. This test measures the angle of incidence to the rudder by measuring the flow field between the propeller and the horn rudder in the presence of the stern return, propeller and horn rudder. Z-axis means height direction of rudder and D means diameter of propeller. The x-axis represents the incident angle of the propeller wake relative to the leading edge of the rudder. Referring to FIG. 11, it can be seen that propeller wake incident angles having different signs are generated at the upper and lower sides of Z / D = 0 (propeller axis) and thus have an opposite effect on the rudder. This phenomenon is inevitable due to the propeller's rotational characteristics, and the loss of lift is inevitable when the rudder is rotated at an angle. In addition, the angle of incidence close to 40 degrees appears at the position Z / D = 0.15, but the angle of incidence of less than 20 degrees appears in the region of Z / D ≥ 0.2, indicating that the rudder incidence angle is formed differently according to the height of the rudder.

Therefore, the present invention provides a separate rudder of the ship as shown in Figure 7 to solve the above problems, the separate rudder according to the present invention, is connected to the steering gear room (steering gear room) 6 is connected to the rotary shaft to operate A lower rudder (5) having a rudder bulb (10) at its lower end and a rotary shaft connected to a shoe piece (7), and having a rudder bulb (11) at its upper end. It consists of a rudder (8), the upper rudder (5) and the lower rudder (8) is characterized in that to rotate individually at each rudder angle in a completely separated state at regular intervals (D). Hereinafter, the separate rudder according to the present invention will be described in more detail.

The split rudder according to the present invention is completely separated from the upper (hereinafter referred to as 'upper rudder') and the lower (hereinafter referred to as 'lower rudder') at regular intervals D, and the upper rudder 5 and the lower rudder (8) is each rotatable at an arbitrary angle. And both the upper rudder 5 and the lower rudder 8 are equipped with the rudder bulbs 10 and 11 at the ends of the propeller axial direction.

The upper rudder 5 is operated by being connected to the steering gear room 6 by a rotational shaft as in the conventional case, and the lower rudder 8 is connected by a rotational shaft to the shoe piece 7 of the stern bottom. In this case, the lower rudder 8 is installed in the shoe piece 7 so as to be operated by a hydraulically actuated drive device 9.

That is, the upper rudder 5 and the lower rudder 8 are installed in the steering gear room 6 and the shoe piece 7, respectively, and are supplied with driving force therein and receive angles of wake flows of the hull and propeller for each cross section. It will work independently so that it is optimized.

On the other hand, no structure (for example, a rotating shaft or a rod) connecting them between the upper rudder 5 and the lower rudder 8 is provided. That is, an empty space is formed at the separated interval between the upper rudder 5 and the lower rudder 8. When an empty space is formed in the separated space between the upper rudder 5 and the lower rudder 8, drag of the rudder is reduced as much as it can reduce the operating energy of the ship, and propeller hub botex (propeller hub vortex) The rudder surface erosion caused by cavitation can also be avoided.

In this case, it is preferable that the separated space D between the upper rudder 5 and the lower rudder 8 is within 35% of the propeller diameter based on the propeller shaft center. If the size of the gap D is greater than 35% of the propeller diameter, lift loss and cavitation occurring in the gap portion may be a burden.

8 shows a top view of the propeller wake and the rudder when the vessel is operating in a straight line. In general rudders, although the rudder angle is 0 degrees, the propeller wake is introduced at a certain angle of attack, so the lift cannot be completely removed. However, in the case of the separate rudder according to the present invention, the angle of attack of the upper rudder and the lower rudder can be properly adjusted to minimize the angle of attack, and the lift and drag can be minimized. In addition, since the angle of attack is minimized in the case of the separate rudder according to the present invention, cavitation occurring in the body of the rudder can be reduced.

9 and 10 show top views of propeller wake and rudder when the ship is turning to starboard and port. In the case of general rudder, lift offset of upper and lower rudder occurs, so the rudder angle should be larger to obtain the desired steering force or lift. Too large a rudder angle can increase lift, but strong cavitation can occur at the suction side of the rudder, causing severe erosion on the other surface. However, in the case of the split rudder according to the present invention, the desired lift force can be efficiently obtained by setting the rudder angles of the upper rudder and the lower rudder to the incidence angle of the suction flow, and the damage angle of the flow is relatively small, thus preventing damage due to cavitation. can do.

The above description is merely illustrative of the technical idea of the present invention, and various modifications, changes, and substitutions may be made by those skilled in the art without departing from the essential characteristics of the present invention. will be. Accordingly, the embodiments disclosed in the present invention and the accompanying drawings are not intended to limit the technical spirit of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by the embodiments and the accompanying drawings. . The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

1: rudder 2: propeller
3: Horn-Ta 4: Full Hit
5: upper rudder 6: steering gear room
7 shoe piece 8 lower rudder
9 driving device 10, 11 rudder bulb

Claims (6)

The upper rudder having a rudder bulb connected to the steering gear room and having a rudder bulb at its lower end, and the lower rudder having a rudder bulb connected at the upper end and operating with a rotating shaft at the upper end. A rudder of a ship having a rudder bulb, characterized in that the rudder rotates individually at each rudder angle in a completely separated state at regular intervals. The method of claim 1,
The upper rudder and the lower rudder are completely separated at intervals of up and down symmetry around the propeller shaft, separated rudder of the ship having a rudder bulb. The method of claim 1,
The separation between the upper rudder and the lower rudder is within the range of 35% of the propeller diameter relative to the center of the propeller shaft. The upper and lower rudders, which are structurally completely separated, are connected and driven to the steering gearroom and the shoepiece, respectively, and the lower end of the upper rudder and the upper end of the lower rudder are provided with a rudder bulb, and the upper rudder and the lower rudder are respectively Method for producing a separate rudder of the ship having a rudder bulb, characterized in that to rotate individually at the rudder angle. The method of claim 4, wherein
The upper rudder and the lower rudder are completely separated by a vertical symmetrical interval with respect to the propeller shaft, completely separated by the upper rudder and the lower rudder, the method of manufacturing a separate rudder of the vessel to drive separately. The method of claim 4, wherein
The separated gap between the upper rudder and the lower rudder is within the range of 35% of the propeller diameter with respect to the center of the propeller shaft. Manufacturing method.

Images