KR20110109307A - Ship rudder using its upper or lower part alone and having rudder bulb - Google Patents

Abstract

The present invention relates to a rudder for ships that reduces lift loss, reduces cavitation occurring on the surface, and increases hull efficiency. More specifically, the rudder is applied only to one side of the propeller shaft above or below the propeller shaft. By providing a rudder bulb at the end of the propeller axial direction, it is related to a ship rudder using only a part of the body, characterized in that the lifting force is canceled due to the propeller wake incident angle of a different sign.

Description

Ship rudder using its upper or lower part alone 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 a rudder which is connected to the steering gear room by a rotating shaft, the lower end of the body is located above the propeller shaft, characterized in that the lower end of the body is provided with a rudder bulb The present invention proposes a rudder for ships that uses only a portion of the body and has a rudder bulb.

In another aspect, the present invention, the rudder is connected to the shoe piece to operate as a rotating shaft, the upper end of the body is located below the propeller shaft, the upper end of the body using a portion of the body, characterized in that it has a rudder bulb A ship rudder having a rudder bulb is presented.

According to the present invention, one-sided angle setting of the rudder located only on the upper or lower portion of the propeller shaft is possible, so that 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 is located only on the top or bottom of the propeller shaft in shape to avoid rudder surface erosion caused by propeller hub vortex cavitation. Other bulbs increase the hull wake by reducing the stern constriction. Therefore, increasing the hull efficiency (ηH = (1-t) / (1-w), t: thrust reduction factor, w: wake) contributes to increase the propulsion efficiency of the ship. It is thought to have a positive effect on the development of the domestic shipbuilding industry in connection with the improvement of propulsion efficiency and maneuverability.

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 rudder applied only to the stern and propeller shaft upper portion of the vessel.
Figure 8 is a rudder applied only to the stern and propeller shaft lower portion of the ship.
9 is a layout of the propeller inflow and the rudder applied only to the propeller shaft upper portion according to the present invention during the straight operation of the vessel.
10 is a layout of the propeller inflow and the rudder applied only to the propeller shaft upper portion according to the present invention during the starboard turn of the ship.
Figure 11 is a layout of the propeller inflow and the rudder applied only to the propeller shaft upper portion according to the present invention when the ship is turning port.
12 is an angle of incidence distribution for 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.

12 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. 12, 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), thereby adversely affecting 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 ship rudder using only a portion of the body as shown in Figures 7 and 8 to solve the above problems, the present invention is applied to the rudder only on one side of the propeller shaft above or below the propeller shaft. However, the propeller axial end of the rudder is characterized in that it comprises a rudder bulb (rudder bulb). More specifically, the present invention, the rudder (5) is connected to the steering gear room (steering gear room) 6 is connected to the rotary shaft and the lower end of the body is located above the propeller shaft and the lower end of the body is a rudder bulb Or a rudder 8 which is connected to and operated by a rotational shaft to a shoe piece 7, the upper end of which is located below the propeller shaft, and the upper end of the body having a rudder bulb. It is characterized by (Fig. 8). Hereinafter, the ship rudder according to the present invention will be described in more detail.

The present invention is to use the characteristics of the rudder incidence angle as described above, in order to prevent the incident angle of the different sign is generated in the upper and lower parts of the rudder relative to the propeller axis, thereby canceling the lift, Figure 7 As shown in FIG. 8, the rudder 5 was installed only on the propeller shaft, or as shown in FIG. 8.

As shown in FIG. 7, the rudder 5 installed only on the propeller shaft is connected to the steering gear room 6 by a rotation shaft as in the conventional case. And the rudder 8 is installed only on the propeller shaft lower portion as shown in Figure 8 is connected to the rotating shaft to the shoe piece 7 of the stern bottom, in this case the rudder 8 is installed in the shoe piece 7 to operate hydraulically To be operated by the drive device 9.

When the rudder 5 is installed only on the propeller shaft as shown in FIG. 7, since the propeller wake incident angle at which the lower sign is different from that of the existing rudder does not occur, the lift force is maintained without being canceled. And if the rudder 8 is provided only on the lower propeller shaft as shown in FIG. 8, since the propeller wake incident angle different from the upper sign which would have occurred if the existing rudder does not occur, the lift force is maintained without being canceled. In addition, in the case of FIGS. 7 and 8, the required inertia (lift) can be secured even with a small angle of attack, thereby reducing the amount of cavitation generated on the rudder surface and reducing the possibility of surface erosion.

Meanwhile, in the case of FIG. 7, the central axis of the bulb 10 installed at the lower end of the body of the rudder 5 is preferably positioned to coincide with the central axis of the propeller shaft, and in the case of FIG. 8, the central axis of the rudder 8 is installed at the upper end of the body of the rudder 8. The central axis of the bulb 11 is preferably positioned to coincide with the central axis of the propeller shaft.

Of course, in this case, the lift force is not canceled due to the propeller wake incident angles having different signs. In the case of FIGS. 7 and 8, the size of the rudders 5 and 8 is greatly reduced compared to the conventional horn rudders, which is very efficient in terms of cost, and accordingly, the torque applied to the rudder is also formed small. The capacity of the gear (FIG. 7) or the drive (FIG. 8) can be greatly reduced.

Figure 9 shows the propeller inflow and the top view of the rudder applied only to the propeller shaft top according to the present invention during the straight navigation of the vessel. 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 present invention, the angle of attack can be adjusted to 0 degrees by appropriately adjusting the rudder angle applied only to the propeller shaft, and the lift and drag can be minimized. In addition, since the angle of attack is minimized, cavitation occurring in the other body can be reduced. The same applies to the use of the rudder only under the propeller shaft.

Figures 10 and 11 show the propeller inflow and the top view of the rudder applied only to the propeller shaft top according to the present invention during the starboard and port turn of the ship. 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 surface (port) of the rudder, causing severe erosion on the rudder surface. However, in the present invention, the desired lift force can be efficiently obtained by setting the rudder angle applied only to the propeller shaft to the incidence angle of the suction flow, and at this time, the angle of attack of the flow is not large so that damage due to cavitation can be prevented. have. The same applies to the use of the rudder only under the propeller shaft.

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: electric drive
5: Rudder applied only to the propeller shaft upper part
6: steering gear room
7: shoe piece
8: Rudder applied only to the lower part of the propeller shaft
9: driving device
10, 11: rudder bulb

Claims (5)

Rudder is applied to only one side of the propeller shaft above or below the propeller shaft, characterized in that the rudder propeller axial end is provided with a rudder bulb, using only a part of the body and having a rudder bulb. A rudder which is connected to the steering gear room by a rotational axis and coincides with the propeller shaft centerline, wherein the lower end of the body is located above the propeller shaft, and the lower end of the body is provided with a rudder bulb. A rudder for ships with rudder bulbs. The method of claim 2,
Bulb center axis which is installed at the lower end of the body of the rudder is characterized in that it is located in accordance with the propeller shaft, using a portion of the body rudder for ships having a rudder bulb. A rudder that is connected to and operated by a rotating shaft, wherein the upper end of the body is positioned below the propeller shaft, and the upper end of the body is provided with a rudder bulb. Rudder for ships. The method of claim 4, wherein
The bulb central axis is installed at the upper end of the body of the rudder, characterized in that the position to match the propeller shaft, using only a portion of the body rudder for ships having a rudder bulb.

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