KR102659729B1 - Asymmetric rudder structure for twin propeller ship - Google Patents

Abstract

The present invention relates to an asymmetric rudder structure mounted on a twin-axle ship: the rudder is based on a structure with a bulb 40 between the upper rudder 20 and the lower rudder 30, and the upper rudder 20 And the lower rudder 30 is characterized in that it is arranged symmetrically with respect to the hull center line (C1) and is formed asymmetrically with respect to the center line of each rudder stock (C2).
Accordingly, by improving the structure of the rudder and bulb connected to the skeg of the twin-axle ship, the resistance characteristics are improved by matching the wake, which has the effect of improving energy efficiency according to the propulsion of the ship.

Description

Asymmetric rudder structure for twin propeller ship}

The present invention relates to an asymmetric rudder structure for a twin-axial ship, and more specifically, to an asymmetric rudder structure for a twin-axial ship to improve resistance characteristics by improving the structure of the rudder connected to the skeg of the twin-axial ship.

A twin-shaft ship is a ship equipped with two engines and two propellers, and has the advantage of being able to distribute propulsion and operate even when the engine fails. Twin-axle ships can be applied not only to warships and other special ships, but also to passenger ships, ultra-large container ships, and LNG carriers. However, because the shape influence coefficient according to 3D analysis is larger for the twin axis line than the single axis line, the single axis line appears to be somewhat superior in terms of resistance performance.

As prior art documents related to the improvement of the resistance characteristics of twin shaft lines, Korean Patent Publication No. 1856865 (Priority Document 1), Korean Patent Publication No. 2014-0106167 (Priority Document 2), etc. are known.

According to prior literature 1, the underwater wing is located between stations 1 and 2 in the longitudinal direction of the ship, and is located between 30% and 60% of the design draft from the bottom of the ship in the height direction of the ship, and is -5 for the design draft. It has a structure that slopes at an angle between degrees and ??10 degrees. Accordingly, the effect of reducing the increase in resistance is expected by improving the sudden pressure drop in the area between the skeg.

Prior document 2 includes a rudder with an asymmetric cross-sectional shape that is installed at the rear of the propeller and adjusts the direction of operation, with one side having a flat shape and the other side having a convex shape, corresponding to the rotation direction of the propeller. Set the direction of the convex surface. Accordingly, it is expected to be advantageous in reducing propulsion resistance, reducing loss of propulsion and efficiently adjusting the sailing direction.

However, according to the above-mentioned prior literature, the technical idea of applying rudder bulbs is not considered, which presents limitations in expecting the effect of improving ship energy efficiency.

Korean Patent Publication No. 1856865 “Flow control device for energy saving of twin-axle vessel” (Publication date: 2018.04.25.) Korean Patent Publication No. 2014-0106167 “Twin-axle ship and rudder for reducing propulsion loss thereof” (Publication date: 2014.09.03.)

The purpose of the present invention to improve the conventional problems described above is to improve the structure of the rudder and bulb connected to the skeg of the twin-axle ship to improve the resistance characteristics by matching the wake, an asymmetric rudder structure of the twin-axle ship. is to provide.

In order to achieve the above object, the present invention is an asymmetric rudder structure mounted on a twin-axle ship: the rudder is based on a structure equipped with a bulb between the upper rudder and the lower rudder, and the upper rudder and the lower rudder It is characterized in that it is arranged symmetrically based on the hull center line and is formed asymmetrically based on the center line of each rudder stock.

According to the detailed configuration of the present invention, when the twin axis ship is propelled outward, the upper rudder is located more inward than the lower rudder.

According to the detailed configuration of the present invention, the upper rudder and the lower rudder are located in opposite directions with respect to the rudder stock center line.

According to the detailed configuration of the present invention, the bulb is characterized in that it is formed with an oval cross-section at a position where its center line coincides with the rudder stock center line.

According to the detailed configuration of the present invention, the axis passing through both ends of the rudder is characterized in that it maintains a twist angle with the axis passing through both ends of the bulb.

As described above, according to the present invention, by improving the structure of the rudder and bulb connected to the skeg of a twin-axle ship, the resistance characteristics are improved by matching the wake, which has the effect of causing an improvement in energy efficiency according to the propulsion of the ship.

Figure 1 is a schematic diagram of the rudder according to the present invention viewed from the stern to the line.
Figure 2 is a schematic diagram showing the conventional rudder compared to the rudder according to the present invention.
Figure 3 is a schematic diagram showing the rudder according to the present invention in side and main cross sections.
Figure 4 is image data showing simulation results of the conventional and present invention rudders

Hereinafter, embodiments of the present invention will be described in detail based on the attached drawings.

The present invention proposes a rudder structure with an asymmetrical shape mounted on a twin-axle ship. The main point is to improve the structure of the rudder connected to the skeg for twin-axle ships, but it is not necessarily limited to this. The skeg is additionally attached to the stern to improve straight-line stability, but it affects steering performance and resistance characteristics.

According to the present invention, the rudder is based on a structure equipped with a bulb 40 between the upper rudder 20 and the lower rudder 30.

Referring to Figure 1, the upper rudder 20, lower rudder 30, and bulb 40 that constitute the rudder are shown. By applying a bulb (40) to the rudder, it prevents erosion due to the discontinuous shape, improves self-propelled performance, and ultimately contributes to improving energy efficiency. Typically, in the wake, a strong vortex generated from the propeller hub complicates the flow around the rudder and causes rotational energy loss.

In addition, according to the present invention, the upper rudder 20 and the lower rudder 30 are arranged symmetrically with respect to the hull center line (C1) and are formed asymmetrically with respect to the center line of each rudder stock (C2). do.

Referring to Figures 1 and 2, the upper rudder 20 and the lower rudder 30 are formed asymmetrically. As shown in Figure 2(a), a conventional single-axis or twin-axis rudder is approximately symmetrical with respect to the rudder stock center line (C2). As shown in Figure 2(b), the upper rudder 20 and lower rudder 30 of the present invention are formed asymmetrically with respect to the rudder stock center line (C2). The asymmetric structure of the rudders 20 and 30 responds well to the wake of the hull skeg 10, increasing the possibility of improving resistance and self-navigation factors by reducing wake vortex.

According to the detailed configuration of the present invention, when the twin axis ship is propelled outward, the upper rudder 20 is located more inward than the lower rudder 30.

It is preferred to use the outward propulsion of the twin-axle vessel as shown in Figure 1, but is not limited to this. If the upper rudder 20 is located more inward than the lower rudder 30 based on the hull center line (C1), the flow around the rudder can be simplified to improve self-navigation performance.

According to the detailed configuration of the present invention, the upper rudder 20 and the lower rudder 30 are located in opposite directions with respect to the rudder stock center line C2.

Referring to Figures 2 and 3, the upper rudder 20 and lower rudder 30 are located on opposite sides based on the rudder stock center line (C2). The leading edge and trailing edge of the upper rudder 20 are inside the axis S2 of the bulb 40, and the leading edge and trailing edge of the lower rudder 30 are outside the axis S2 of the bulb 40. Located. The axis S2 of the bulb 40 is a straight line connecting the center point of one end and the center point of the other end. The uniform dimensions of the upper rudder 20 and the lower rudder 30 are determined in consideration of the skeg 10 and other attachments that affect steering performance.

Meanwhile, Figures 1 to 3 are schematic diagrams of the skeg 10 and the rudders 20 and 30, which are expressed somewhat exaggeratedly. In Figure 3, the main cross sections of the upper rudder 20 and lower rudder 30 are shown overlapping with the bulb 40.

According to the detailed configuration of the present invention, the bulb 40 is characterized in that it is formed in an oval cross-section at a position whose center line coincides with the rudder stock center line C2.

In FIG. 2, the axis S2, which is the center line of the bulb 40, is located vertically below the rudder stock center line C2. The bulb 40 is formed with an oval cross-section in which the horizontal width is greater than the vertical height. The upper rudder 20 is connected from the upper surface of the bulb 40 to one side of the axis S2, and the lower rudder 30 is connected to the lower rudder 30 from the lower surface of the bulb 40 to the other side of the axis S2. By applying the asymmetric rudder cross section of this structure, the effect of improving thrust can be obtained by keeping the rudder inflow angle small.

According to the detailed configuration of the present invention, the axis S1 passing through both ends of the rudder is characterized in that it maintains a twist angle with the axis S2 passing through both ends of the bulb 40.

In Figure 3, the axis S1 of the rudder and the axis S2 of the bulb 40 are not parallel but are shown in a twisted state. The rudder axis (S1) is a straight line connecting the center point of the leading edge and the center point of the trailing edge. This is advantageous in forming a wake that flows along the surface of the bulb 40 by dissipating the vortex of the propeller hub. The twist angle between the axes S1 and S2 can be determined in the range of 2 to 12 degrees. This reduces losses due to vortex and simplifies the flow around the rudder to improve self-navigation performance.

At this time, it is preferable that the upper rudder 20 and the lower rudder 30 form an asymmetric structure with respect to each axis S1.

Meanwhile, although omitted in the illustration, it is preferable that at least one of the rudder axis S1 and the bulb 40 axis S2 be installed to maintain a twist angle with respect to the propeller center line.

Referring to Figure 4, the results of computer simulation using the rudder structures of the prior art and the present invention are shown. In the case of a conventional rudder structure as shown in Figure 4(a), the vortex is deepened due to mismatch with the skeg wake, as indicated by the arrow. As shown in Figure 4(b), applying the skeg and rudder structure of the present invention has the effect of improving resistance and self-propelled elements by matching the wake of the hull skeg.

And due to these various design elements, energy efficiency can be expected to improve as twin-axle ships are promoted.

The present invention is not limited to the described embodiments, and it is obvious to those skilled in the art that various modifications and changes can be made without departing from the spirit and scope of the present invention. Accordingly, such variations or modifications should fall within the scope of the patent claims of the present invention.

10: Skeg 20: Upper rudder
30: Lower rudder 40: Bulb
C1: Hull center line C2: Rudder stock center line
S1, S2: axis

Claims (5)

In the asymmetric rudder structure mounted on a twin-axle ship:
The rudder is based on a structure with a bulb 40 between the upper rudder 20 and the lower rudder 30,
The upper rudder 20 and the lower rudder 30 are arranged symmetrically with respect to the hull center line (C1) and are formed asymmetrically with respect to the center line of each rudder stock (C2),
When the twin axis is propulsion outward, the upper rudder 20 is located more inward than the lower rudder 30,
The upper rudder 20 and the lower rudder 30 are located in opposite directions with respect to the rudder stock center line C2,
The bulb 40 is a biaxial asymmetric rudder structure, characterized in that the bulb 40 is formed with an oval cross-section where the horizontal width is greater than the vertical height at a position where the center line coincides with the rudder stock center line C2. delete delete delete In claim 1,
An asymmetric rudder structure with a twin axis, characterized in that the axis (S1) passing through both ends of the rudder maintains a twist angle with the axis (S2) passing through both ends of the bulb (40).

Images