WO2019027126A1

WO2019027126A1 - Duct-type ship energy reducing device

Info

Publication number: WO2019027126A1
Application number: PCT/KR2018/005372
Authority: WO
Inventors: 이승호
Original assignee: 필드지 주식회사
Priority date: 2017-08-04
Filing date: 2018-05-10
Publication date: 2019-02-07
Also published as: KR20190014935A

Abstract

A duct-type ship energy reducing device according to an embodiment of the present invention comprises: a duct disposed to surround a part of the rear protruding part of a ship; and a support part for connecting the rear protruding part to the inner surface of the duct to fix the position of the duct with respect to the rear protruding part. The support part comprises a first support disposed on a first side of the ship and having a first end connected to the rear protruding part and a second end connected to the inner surface of the duct, the ends being curved in opposite directions, respectively. The support part may further comprise a second support disposed on a second side of the ship and having a positive average slope with respect to a propelling shaft of the ship.

Description

Duct type ship energy saving device

The present invention relates to a duct-type ship energy saving device.

Generally, the ship is designed to move by using its propulsive force to propeller the propeller to rotate in the fluid. At this time, a rudder is attached to the rear of the propeller, and as the rudder rotates to the left and right, the direction of flow of the fluid is changed to change the direction of navigation.

In order to achieve a constant speed through the rotation of the propeller, the engine must be driven. At this time, a large amount of fuel is consumed, and the amount of greenhouse gas emissions resulting from the consumption of the fuel is increased. Recently, various studies have been carried out to reduce fuel consumption by reducing energy consumed in propulsion of a ship.

As an example of the fuel saving type technology, it is possible to improve the propulsion efficiency by improving the shape of the rear end of the ship, the propeller, the rudder, etc., or by attaching additional additives, and at the same time, an energy saving device (ESD: Energy Saving Device) Interest.

Among these energy saving devices, a duct is typically used to enhance the propulsion efficiency by attaching an additional adduct. For example, Korean Patent No. 10-1453210, Korean Patent No. 10-1453209, and Korean Patent Laid-Open No. 2016-0149877 disclose various types of duct type energy saving devices.

It is an object of the present invention to provide a duct-type ship energy saving apparatus which reduces the increase of resistance and improves the propulsion efficiency of a propeller by designing a support plate disposed at the port and starboards in accordance with the flow of the fluid. However, these problems are illustrative and do not limit the scope of the present invention.

A duct-type ship energy saving apparatus according to an embodiment of the present invention includes: a duct disposed in a form surrounding a part of a stern protrusion of a ship; And a support portion connecting the stern protruding portion and the inner surface of the duct, wherein the first end connected to the stern protrusion and the second end connected to the inner surface of the duct are bent in directions opposite to each other, And a first support disposed on a first side of the ship.

In one embodiment, the inclination of the first end with respect to the propelling shaft may be greater than the inclination of the second end with respect to the propelling shaft.

In one embodiment, the slope of the first support may decrease from the first end to the second end.

In one embodiment, the support portion may further include a second support disposed on a second side of the ship, the second support having a positive average slope with respect to the propeller shaft of the ship.

The duct-type ship energy saving apparatus according to an embodiment of the present invention may further include a plurality of pins disposed on a second side of the ship and protruding from the inner surface of the duct toward the central axis of the duct have.

In one embodiment, the pin disposed relatively above the plurality of pins may have an average slope greater than the pin disposed relatively below.

In one embodiment, the support portion may further include a third support formed symmetrically with respect to a central vertical plane of the ship, the third support being connected to the stern protrusion and the inner surface of the duct.

Other aspects, features, and advantages will become apparent from the following drawings, claims, and detailed description of the invention.

According to the duct-type ship energy saving apparatus according to an embodiment of the present invention, the first support which is disposed on the starboard and bent at opposite ends in opposite directions minimizes the fluid stagnation at the stern protruding portion, The increase of the resistance can be reduced.

The propulsion efficiency of the propeller can be improved by changing the flow of the fluid from the ascending flow to the descending flow by the second support disposed at the port and having a positive average slope.

The flow of the fluid before passing through the second support is changed from the ascending flow to the descending flow by the pin disposed further on the port side where the flow field can be adversely formed and the size of the resistance acting on the second support is reduced, The propulsion efficiency of the propeller can be improved.

Of course, the scope of the present invention is not limited by these effects.

Fig. 1 is an illustration showing the ideal flow of the fluid to increase the propeller rotation direction and the efficiency of the propeller, and the actual flow of the fluid in the vessel.

FIG. 2 is a right side view showing a stern portion of a ship with a duct-type ship energy saving device according to an embodiment of the present invention. FIG.

3 and 4 are a perspective view and a front view, respectively, showing a stern portion of a ship equipped with a duct-type ship energy saving device according to an embodiment of the present invention.

5 and 6 are enlarged perspective views of the first support and sectional views of the first support taken along lines I-I ', II-II', III-III ', IV-IV' and V-V ', respectively.

FIG. 7 is a cross-sectional view taken along the line I-I ', II-II', III-III ', IV-IV' and V-V ' This is a picture that expresses existence.

8 is a graph showing the flow rate and the streamline of the fluid flowing around the stern protrusion S, obtained through computational fluid dynamics (CFD) simulation.

9 and 10 are respectively an enlarged perspective view of the second support and a cross-sectional view of the second support along VI-VI 'and VII-VII', respectively.

11 is a perspective view showing a stern portion of a ship with a duct-type ship energy saving device further including a pin.

12 is a perspective view of a ducted ship energy saving device including a pin according to one embodiment.

13 is a perspective view showing a stern portion of a ship with a duct-type ship energy saving device further including a third support member.

FIG. 14 is a diagram comparing v-w velocity vector fields of a fluid in a yz section of a duct-type ship energy saving apparatus according to an embodiment of the present invention.

15 is a diagram illustrating a change in the v-w velocity vector field of a fluid at the yz cross section of a propeller when a duct-type ship energy saving device according to an embodiment of the present invention is installed on a ship.

The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated in the drawings and described in the detailed description. The effects and features of the present invention and methods of achieving them will be apparent with reference to the embodiments described in detail below with reference to the drawings. However, the present invention is not limited to the embodiments described below, but may be implemented in various forms.

In the following embodiments, the terms first, second, etc. are used for the purpose of distinguishing one element from another element, rather than limiting.

In the following examples, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise.

In the following embodiments, terms such as inclusive or possessive are intended to mean that a feature, or element, described in the specification is present, and does not preclude the possibility that one or more other features or elements may be added.

In this specification, the x-axis is the axis passing through the bow and stern of the ship, the y-axis is the axis passing through the port of the ship and the starboard, and the z-axis is the axis passing through the bottom of the ship and the upper deck.

In this specification, the direction in which the ship moves forward is defined as forward / forward and vice versa as rear / back. On the other hand, left and right are defined based on the direction in which the ship is moving forward.

In this specification, the propulsion axis (PA) means the axis on which the propeller rotates as the ship moves forward.

In this specification, the term " side " refers to the side of the ship, and represents either a port or a starboard.

In this specification, the design speed means the speed at which the shipyard must satisfy the contract terms in the shipbuilding contract, at a rate that can be reached at 85% or 90% of the maximum output of the main engine mounted on the ship .

In the drawings, components may be exaggerated or reduced in size for convenience of explanation. For example, the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of explanation, and thus the present invention is not necessarily limited to those shown in the drawings.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein like reference numerals refer to like or corresponding components throughout the drawings, and a duplicate description thereof will be omitted .

A duct disposed in front of the propeller or surrounding the propeller can reduce the energy by improving the performance of the propeller by controlling the flow of the fluid to the propeller. Therefore, when installing the duct, it is necessary to examine the fluid flow (velocity vector field) at the end of the propeller.

Figure 1 is an illustration of an ideal flow of fluid to increase the propeller rotation direction and the efficiency of the propeller and the actual flow of fluid in the vessel.

When viewed from the stern side, the propeller of most ships turns clockwise as shown in (a). It is known that the efficiency of the propeller is further increased when the fluid introduced into the propeller flows into the propeller while rotating in the direction opposite to the direction of rotation of the propeller. Therefore, when the propeller rotates in the clockwise direction as shown in (a), it is preferable that the v-w velocity vector field indicating the velocity in the y and z directions of the fluid passing through the yz plane is rotated counterclockwise as shown in (b).

1 (c) shows the actual flow (velocity vector field) of the fluid in the bare hull state. (c), the most upstream flow is generated on the starboard side, and a flow favorable to the propeller efficiency is formed. However, a descending flow occurs near the central portion of the propeller, and compared with the ideal flow (b) There are some disadvantages to efficiency. On the other hand, the middle part of the port is inferior in propeller efficiency because a downward flow occurs, but the upward flow is generated mostly in the far part from the center part, which is not good for the propeller efficiency.

Therefore, when placing the duct, the component should be designed so that the actual velocity vector field approaches the ideal velocity vector field. However, the existing duct has a problem that the propeller efficiency is low by designing the support without considering the difference between the port side and the starboard side and the difference in the flow of the fluid at the side closer to the central portion and the flow at the far side.

FIG. 2 is a right side view showing a stern portion of a ship with a duct-type ship energy saving device according to an embodiment of the present invention. FIG. The duct-type ship energy saving device of the present invention may be disposed in front of a propeller (P) which is coupled to a ship's stern protrusion (S) and provides a thrust, or may be disposed so as to surround a propeller (P). In FIG. 2, the duct-type ship energy saving device is arranged in front of the propeller (P). The duct-type ship energy saving device according to one embodiment can improve the efficiency of the propeller by controlling the flow of the fluid flowing into the propeller (P) behind the duct (10) or the duct (10).

Referring to FIG. 2, in a central region close to the stern protrusion S, a downstream (DS) flows along the center hull of the ship. On the other hand, in a region slightly further away from the stern protrusion S, that is, near the duct 10, an upstream flow (US) flows.

According to one embodiment, the first end (Figs. 3 and 21-1) connected to the stern protrusion S and the second end (Figs. 4 and 21-2) connected to the inner surface of the duct 10 are bent The flow of the fluid flowing near the first stage 21-1 and the flow of the fluid flowing near the second stage 21-2 can be adjusted differently through the support 1 (Figs. 3 and 21). That is, the propulsion efficiency of the propeller P can be improved through the structural characteristics of the first support 21, which will be described below.

3 and 4 are a perspective view and a front view, respectively, showing a stern portion of a ship equipped with a duct-type ship energy saving device according to an embodiment of the present invention. In FIGS. 3 and 4, for the sake of convenience, the first support 21 is illustratively disposed on the starboard of the ship except for the propeller of the ship, but the present invention is not limited thereto.

A duct-type ship energy saving apparatus according to an embodiment of the present invention includes a duct (10) and a support portion (20).

Referring to FIG. 3, the duct 10 is arranged to surround at least a part of the stern protrusion S from outside. For example, the duct 10 has a shape in which the front side and the rear side are open, and can have a space therein. The duct 10 may have a complementary shape to the outer surface of the stern protrusion S, and the cross section of the duct 10 may have various structures such as a circle and an ellipse. According to one embodiment, the duct 10 may have a structure such that the radius of the cross section becomes larger toward the front of the ship, such as a lamp shade. In this case, the fluid introduced from the front of the duct 10 having a wide 'inlet' will escape to the rear of the duct 10 with a narrow 'outlet', so that the outlet velocity of the fluid Which is faster than the inflow rate. This increases the velocity of the fluid flowing into the propeller disposed behind the duct 10 as compared to when the duct 10 is absent. In this case, the duct 10 can function as an accelerating duct. Alternatively, the duct 10 may have a structure in which the radius of the cross section increases as the duct 10 moves toward the rear direction of the ship. In this case, the duct 10 may function as a deceleration duct. On the other hand, the duct 10 can suppress the generation of a vortex generated in the vicinity of the stern protrusion S, and can play a role of equalizing the velocity distribution of the fluid flowing in the propeller P in the x direction.

A support portion (20) is disposed inside the duct (10). The support portion 20 connects the stern protrusion S and the inner surface of the duct 10 to fix the position of the duct 10 to the stern protrusion S. Since the support portion 20 is disposed inside the duct 10, it can act as a resistance to obstruct the flow of the fluid flowing into the duct 10. Accordingly, in the present invention, the shape of the support portion 20 can be modified to improve the propelling efficiency of the propeller so as to change the flow of the fluid flowing into the duct 10 and minimize the increase of the resistance.

The support portion 20 may include a plurality of supports having different shapes and positions. In FIGS. 3 and 4, a first support 21 and a second support 22 are arranged on a starboard and a port, respectively. In one embodiment of the present invention, the first support 21 and the second support 22 have different shapes. Hereinafter, the structures of the first support 21 and the second support 22 are different from each other, Describe the effect in turn.

3 and 4, the first end 21-1 of the first support 21 connected to the stern protrusion S and the second end 21-2 connected to the inner surface of the duct 10 are connected to each other Bend in the opposite direction. More specifically, the first end 21-1 of the first support 21 is bent forward and the second end 21-2 of the first support 21 is bent forward. That is, the first support base 21 may have a structure in which both sides of the plate are bent and bent in opposite directions. Because of this structural feature, the flow of the fluid in the first hinge side moving in the direction in which the propeller ascends is changed to improve the propelling efficiency of the propeller, which will be described later.

5 and 6 are enlarged perspective views of the first support and a cross-sectional view of the first support along the lines I-I ', II-II', III-III ', IV-IV' and V-V, respectively.

5 and 6, the first support 21 may have a streamlined plate shape. At this time, the plate refers to a shape having a longer length in the left-right direction (y) and the back-and-forth direction (x) than the thickness in the up-and-down direction (z). In particular, the length of the first support frame 21 in the left-right direction y may be longer than the length of the fore-and-aft direction x. Each longitudinal section of the first support 21 has a streamlined airfoil shape to minimize resistance due to fluid flowing into the interior of the duct 10. At this time, the airfoil can have various shapes.

According to one embodiment, the upper boundary line of the first support frame 21 may be flat, and the lower boundary line may have a convex downward structure. Alternatively, both the upper border and the lower border may have a convex structure, and the lower border line may have a convex structure. That is, the curvature of the upper surface of the first support 21 may be gentler than that of the lower surface. The velocity of the fluid flowing under the lower surface of the first support 21 having such a structure is fast and the velocity of the fluid flowing on the upper surface is relatively slow. In this case, the velocity component in the upward direction of the fluid passing through the rear end of the first support table 21 becomes large, so that the upward flow becomes strong and the propelling efficiency of the propeller P increases.

According to one embodiment, the slope of the first stage 21-1 with respect to the propulsion shaft PA may be greater than the slope of the second stage 21-2 with respect to the propulsion shaft PA.

The inclination of the first stage 21-1 with respect to the propeller shaft PA is determined by the angle of the airfoil section (section cut along the line II ') cut along the boundary between the first support 21 and the stern protrusion S, 0.0 > PA. &Lt; / RTI > The inclination of the second stage 21-2 with respect to the propelling shaft is determined such that the end face of the airfoil cut along the boundary between the first support 21 and the inner surface of the duct 10 0.0 > PA. &Lt; / RTI >

The 'slope of the airfoil section' may be defined as the slope or angle of the chord line of the airfoil section with respect to the propulsion shaft PA. In FIG. 6, it is assumed that a flat upper boundary line of the cross section of the first support 21 is a protrusion line for convenience. That is, 'slope' in FIG. 6 means an angle formed by the upper boundary of the end surface of the first support 21 with the propeller shaft PA. In FIG. 6, the slope of the first stage 21-1 with respect to the propeller shaft PA is 0 ° for convenience, but the present invention is not limited thereto. That is, the inclination of the first stage 21-1 with respect to the propeller shaft PA may have a positive or negative value depending on the size, shape, and the like of the ship.

Sectional view of the airfoil in the first stage 21-1, the airfoil section in the first stage 21-1 is inclined more upward than the airfoil section in the second stage 21-2. As described above, in the vicinity of the hull, that is, in the vicinity of the center portion of the stern projection S, a downward flow from I 'to I occurs. On the other hand, in a region farther from the central portion of the stern projection S, that is, in the vicinity of the duct 10, an upstream flow from V 'to V is generated. Accordingly, in the present invention, by increasing the inclination? _IS of the first stage 21-1 to minimize the resistance due to the downward flow and reducing the inclination? _OS of the second stage 21-2, Minimize the resistance.

According to one embodiment, the difference? _IS between the slope S _IS of the first stage 21-1 and the mean slope S _M of the first support 21 can be 0 to 20 °, The difference? _OS between the slope S _OS of the second stage 21-2 and the average slope S _M of the first support stage 21 may be -20 to 0 °.

In the present specification, the difference in slope is expressed by an angle. In this case, the angle in the counterclockwise direction has a positive angle, and the angle in the clockwise direction has a negative angle.

In this specification, the 'average slope' means the average of several airfoil section slopes cut parallel to the propeller shaft (PA). That is, from the first end 21-1 to the second end 21-2 of the first support 21, the average value of the slope of the cross section of the airfoil depending on the position is the Becomes the average slope ( _SM ). Alternatively, when it is assumed that the both ends of the 'flat plane' are bent to form the first support 21, the average slope S _M is determined by 'a first support 21 in the form of a flat plate' ). &Lt; / RTI > Alternatively, the average slope S _M of the first support 21 may mean the extent to which the first support 21 is wholly rotated in the reference state. In FIG. 6, the average slope of the first support 21 is represented by a line S _M , and the slope of the III-III 'airfoil section is illustrated as an average slope (S _M ).

At this time, the difference? _IS between the slope S _IS of the first stage 21-1 and the mean slope S _M of the first support 21 is _{smaller than the} flatness? (21-1) is bent. Similarly, the difference? _OS 'between the slope S _OS of the second stage 21-2 and the mean slope S _M of the first support 21 is such that the second stage 21-2 is''Is a measure of how much it is bent when compared to the state of'

Referring now to the cross-sectional view of II ', the angle θ _IS between the slope S _IS of the first stage 21-1 and the mean slope S _M may be about 0-20 °. If the first stage 21-1 is bent excessively, the fluid may 'bump' the first support 21, rather the resistance may increase. The optimal value of the angle? _IS depends on the shape, size, and shape of the ship, and therefore can be determined using computer simulation using computational fluid dynamics (CFD) or model simulation using a model ship.

On the other hand, the angle between the slope (S _OS) with the average slope (S _M) if the VV ', see the sectional view, a second end (21-2) (θ _OS) may be between about -20 ~ 0 °. If the second stage 21-2 is excessively curved, the fluid may 'strike' the first support 21, but the resistance may increase. The optimum value of the angle? _OS depends on the shape, size, and shape of the ship, and therefore can be determined using a computer simulation using computational fluid dynamics (CFD) or a model simulation using a model ship.

According to one embodiment, the slope of the first support 21 may decrease from the first end 21-1 to the second end 21-2. The 'slope of the first support 21' means the slope of the cross section of the airfoil depending on the position. 6 shows the mean slope line S _M and the slope line S _IS of the airfoil from the first end 21-1 to the second end 21-2 of the first support 21, (Θ _IS , θ ₂ , θ ₃ , θ ₄ , θ _OS ) formed by the S _II , S _III , S _IV and S _OS can be made smaller. At this time, the slopes (? _IS ,? ₂ ,? ₃ ,? ₄ ,? _OS ) of the airfoil section of the first support 21 can be continuously changed. In other words, the surface of the first support 21 can have a smooth curved surface without a sudden breaking portion. In this case, the resistance can be minimized without the area where the fluid stagnates.

FIG. 7 is a cross-sectional view of the first support 21 of FIG. 5 taken along lines I-I ', II-II', III-III ', IV-IV' It is a picture that it is inclined downward.

According to one embodiment, the first support 21 may have a negative average slope &thetas; ₂₁ with respect to the propulsion shaft PA. The average slope (θ ₂₁₎ of the first support 21 may be -20 ~ 0 °. That is, the first support 21 can be inclined such that the leading edge is directed downward as a whole.

Referring again to FIG. 1 (c), looking at the v-w velocity vector field of the fluid at the yz cross section of the duct, most of the fluid passing through the duct, except for the center, is ascending.

Referring to FIGS. 2 and 7, a relatively upward flow US flows near the inner surface of the duct 10, and a downward flow DS relatively flows in a region near the stern protruding portion S. That is, toward the second end 21-2 of the first support, that is, in FIG. 7, an upward flow flows toward the VV 'sectional view direction. Therefore, when the front end of the first support 21 is tilted downward, the angle of the first support 21 is reduced with respect to the flow of the upward flow. That is, when the average slope? ₂₁ of the first support is maintained at a negative angle, the resistance by the fluid can be reduced.

If the first support 21 is too tilted or tilted to the opposite side, the fluid may 'bump' the first support 21, rather the resistance may increase. The optimum value of the mean slope of the first support 21 may depend on the shape, size, and shape of the ship, and may thus be determined using computer simulation using computational fluid dynamics (CFD) or model simulation using a model ship have.

On the other hand, a downward flow relatively occurs at the central portion of the duct 10, that is, near the stern projection S. Accordingly, the first end 21-1 of the first support member bends the leading edge relatively upward to reduce the angle of attack with the downward flow. That is, the first support 21 is tilted downward as a whole, and only the first end 21-1 is tilted upward, whereby the resistance by the fluid can be reduced for each position.

In FIG. 7, the slope S _IS of the first stage 21-1 is parallel to the propeller shaft PA for convenience. However, the present invention is not limited thereto.

FIG. 8 is a graph showing the flow rate and the stream line of the fluid flowing around the stern protrusion S, obtained through computational fluid dynamics (CFD) simulation. In FIGS. 8A to 8D, the region with a high concentration is a reference region having a relative speed of 1. Each line separated by concentration is a kerosene line followed by a point at which it decreases by 10% at the reference speed. The area with a low concentration means a place where the relative velocity is zero and the fluid stagnates. The design speed of the simulated ship was 14 knots and the velocity of the fluid was 1.273 m / s to match the froude number on computer simulation.

In the figure located on the left side of Fig. 8, only the flow velocity distribution is represented through the concentration, and in the figure arranged on the right side, the streamline of the fluid flowing around the hull is also expressed.

8 (a) shows a bare hull state without a duct and a supporting portion. As described above, a descending flow flows in a region closer to the stern projection S and an upward flow flows in a region far from the stern projection S.

8 (b) shows a case in which the starboard 21 'on the starboard side is installed at 0 ° with respect to the propeller shaft PA. In this case, it can be confirmed that the velocity of the fluid is zero near the inner boundary of the area A, that is, the support and the stern protrusion S. As the fluid stagnates, the resistance to the support greatly acts, and the propulsion efficiency decreases due to the lowering of the speed of the fluid flowing into the propeller.

Fig. 8C shows a case in which the star support 21 " is rotated by 20 DEG in the downward direction. The reason why the support is rotated and disposed is to reduce the angle of attack of the starboard current with respect to the ascending current to reduce the resistance, as described above. As a result, the velocity of the ascending current increases near the second stage 21-2, but the stream line also becomes more complicated in the vicinity of the inner boundary of the supporter and the stern protrusion S.

FIG. 8 (d) shows a case where a duct-type ship energy saving device according to an embodiment of the present invention is installed. In the experimental example of the present invention, the first support 21 is disposed such that the average inclination (average angle) of the first support 21 is -20 占 and the first end 21-1 and the second end 21 -2) was twisted so that the slopes were 20 and -20 degrees, respectively, with respect to the average slope. That is, the first support 21 of (d) has such a structure as to grasp both ends of the support 21 '' of (c). At this time, it can be seen that the phenomenon of congestion of the fluid near the first stage 21-1 is reduced, and the twisting of the stream line is alleviated.

That is, the structure of the first support 21 of the present invention, that is, the first end 21-1 connected to the stern protrusion S and the second end 21-2 connected to the inner surface of the duct 10, Due to the fin structure, it is possible to minimize an increase in resistance caused by stagnation of the fluid near the hull where a downward flow is generated.

The resistance reduction effect described above can be applied regardless of whether the first support member 21 is located at the port or starboard side. However, in the present invention, the position where the first support table 21 is disposed is selected as either the port or the starboard depending on the direction of rotation of the propeller. Specifically, when the propeller of the ship rotates in the clockwise direction when viewed from the stern side, the first support base 21 is disposed on the starboard. Conversely, when the propeller rotates in the counterclockwise direction, the first support 21 is disposed at a port.

The reason why the first support 21 is selectively disposed in the port or starboard according to the rotation direction of the propeller is to obtain the effect of reducing the resistance as well as the effect of regulating the flow of the fluid to increase the propelling efficiency of the propeller .

As described above, for example, when the propeller rotates in the clockwise direction, the fluid flowing into the propeller must be rotated in the counterclockwise direction to increase the propelling efficiency of the propeller (see FIG. 1). At this time, on the starboard side, the propeller rotates from top to bottom, so that it is preferable that the fluid passing through the starboard side of the duct 10 is directed upward from below, that is, . Therefore, it is effective that, in the starboard side, the upward flow near the inner surface of the duct 10 is left as it is, and the downward flow near the stern protruding portion S is changed. In the present invention, this effect is achieved through the first support 21.

On the contrary, since the propeller rotates from the bottom to the top in the port side, it is preferable that the fluid passing through the port side of the duct 10 is directed downward, that is, (See Fig. 1). In the present invention, the propulsion efficiency is improved by controlling the flow of the fluid in the second side through the second support 22, which will be described below.

According to one embodiment, the support 20 includes a second support 22 disposed on a second side of the vessel, i.e., a port, and having a positive average slope &thetas; ₂₂ with respect to the propulsion axis PA of the vessel .

Referring to Fig. 9, the second support 22 is disposed on the second hinge side. The second support base 22 also connects the stern protrusion S and the duct 10 like the first support base 21 so that the position of the duct 10 can be relatively fixed. When the duct 10 and the stern protrusion S are connected using both the first support 21 and the second support 22, the duct 10 can be more stably supported. According to one embodiment, the second support 22 may have a streamlined plate shape. Each longitudinal section of the second support 22 may have the form of a streamlined airfoil.

In the present invention, the average inclination? ₂₂ of the second support 22 is positive, and the upward flow introduced from the port is guided to be deflected by the second support 22 to be a downward flow. Since the second support rods 22 are arranged to change the fluid flow direction, the overall energy efficiency of the ship can be improved by increasing the resistance but forming the flow field in a direction favorable to the propeller efficiency.

On the other hand, the descending flow in the vicinity of the stern protrusion S in the port side is a "favorable" flow in the resistance surface acting on the second support table 22 inclined in the positive direction. Therefore, unlike the first support 21, the inner end of the second support 22 (the end connected to the aft protrusion S) may not be bent. That is, the inclination of the cross section of the second support table 22 can be constant depending on the position without warping.

Referring to the sectional view taken along the line VI-VI ', VII-VII' in FIG. 10, the shape of the cross-section of the airfoil according to the position of the second support 22 may be constant. At this time, the angle formed between the propulsion shaft PA and the airfoil section, that is, the average inclination? ₂₂ may be 0 to 20 °. Second optimal value of the average slope (θ ₂₂₎ of the support (22) is simulated, so the left and right shape of the vessel, the size, the shape of the wire (streamline) or the like, using a computer simulation or model ships using computational fluid dynamics (CFD) model . &Lt; / RTI >

On the other hand, the shape and inclination of the airfoil section of the second support (22), if the average slope (θ ₂₂₎ is held in an amount, a second support 22 of may vary depending on the location.

According to one embodiment, the lower boundary of the longitudinal section of the second support 22 may be flat, and the upper boundary may have a convex structure. Alternatively, both the upper boundary and the lower boundary may have a convex structure, and the upper boundary line may have a more convex structure than the lower boundary. That is, the curvature of the lower surface of the second support table 22 may be gentler than the curvature of the upper surface. The velocity of the fluid flowing on the upper surface of the second support 22 having such a structure is fast and the velocity of the fluid flowing below the lower surface is relatively slow. In this case, the velocity of the fluid passing through the rear end of the second support table 22 is changed in the downward direction to form a downward flow, thereby contributing to an improvement in the propulsion efficiency of the propeller P.

According to the invention, the average inclination (θ ₂₂₎ that due to the structure that is maintained in an amount, at a second side resistance is changed a little increase of the fluid flow through the one propeller propulsion efficiency of the propeller of the second brace 22 is . Thus, the overall energy efficiency of the ship is improved.

11 is a perspective view showing a stern part of a ship equipped with a duct-type ship energy saving device further including a fin. The duct-type ship energy saving device according to one embodiment is disposed on the second side of the ship, And a plurality of fins 30 protruding from the inner surface of the duct 10 toward the center axis of the duct 10.

As described above, when the propeller rotates in the clockwise direction, a favorable flow field is formed on the starboard side but an adverse flow field is formed on the port side. Accordingly, in the present invention, a pin 30 is additionally installed on the second side where the second support base 22 is disposed to improve the propelling efficiency of the propeller by controlling the flow of the fluid passing through the duct 10.

The fins 30 may protrude from the inner surface of the duct 10 at regular intervals and have a shape capable of rotating the fluid flowing inside the duct 10. At this time, rotating the fluid may mean that the v-w velocity vector field in the yz cross section of the propeller has a shape of rotation as shown in FIG. 1 (b).

According to one embodiment, the pin 30 may have a streamlined plate shape. I.e. each longitudinal section of the fins 30 may have the form of a streamlined airfoil. The shape of the cross section of the airfoil according to the position of the pin 30 may be constant.

According to one embodiment, the lower surface of the pin 30 may be flat and the upper surface may have a convex structure. Alternatively, both the upper boundary and the lower boundary may have a convex structure, and the upper boundary line may have a more convex structure than the lower boundary. That is, the curvature of the lower surface of the pin 30 may be gentle as compared with the curvature of the upper surface. In this case, the downward speed component of the fluid passing through the rear end of the pin 30 becomes large, so that the downward flow becomes strong and the propelling efficiency of the propeller P becomes high.

In one embodiment, the pins disposed relatively above one of the plurality of pins may have an average slope greater than the pins disposed on the relatively lower side. That is, the more the pin 30 is disposed above the ship, the larger the average slope can be.

Referring to FIG. 12, there is illustrated a duct-type ship energy saving device with six

pins

31, 32, 33, 34, 35, 36 attached to the inner surface of the duct 10. The average slope of the airfoil section of each fin is similar to the average slope of the airfoil section S31, S32, S33, S34, S35, and S35, similar to the definition of the average slope of the first support 21 and the second support 22. [ S36) and the propulsion shaft of the ship (? ₃₁ ,? ₃₂ ,? ₃₃ ,? ₃₄ ,? ₃₅ ,? ₃₆ ). At this time, the angle between the pin and the propeller shaft becomes larger toward the upper side, that is, toward the positive z direction. That is, in the embodiment of FIG. 12, for example, the average slope? ₃₁ _- of the pin 31 disposed at the uppermost position is larger than the mean slope? ₃₂ of the pin 32 disposed immediately below, The average slope? _36- of the pin ₃₆ is smaller than the average slope? ₃₅ of the pin 35 disposed immediately _thereabove .

At this time, the average slope of the propulsion shaft PA and each of the fins 30 may be 0 to 20 degrees. In one embodiment, the average slopes (? ₃₁ ,? ₃₂ ,? ₃₃ ,? ₃₄ ,? ₃₅ ,? ₃₆ ) of the

respective pins

31, 32, 33, 34, 35, 14 °, 11 °, 8 °, and 5 °, and the inclination was decreased by 3 ° toward the bottom. The plurality of fins 30 may also have a structure in which the average slope (? ₃₁ ,? ₃₂ ,? ₃₃ ,? ₃₄ ,? ₃₅ ,? ₃₆ ) is maintained in a positive manner similar to the second support 22. As a result, the resistance of the second side increases slightly, but the flow of the fluid through the propeller is changed to improve the propulsion efficiency of the propeller. Thus, the overall energy efficiency of the ship is improved.

According to one embodiment, the fins 30 can be arranged at the same interval from the 7 o'clock direction to the 11 o'clock position when the stern protrusions S are viewed from the stern side. The number and shape of the pins 30, the average slope of each pin, and the like can be optimized using a computer simulation using computational fluid dynamics (CFD) or a model simulation using a model ship.

13 is a perspective view showing a stern part of a ship to which a duct-type ship energy saving device further including a third support 23 is attached.

According to one embodiment, the support portion 20 may further include a third support 23 formed symmetrically with respect to a central longitudinal profile of the ship and connected to the inner surface of the stern protrusion S and the duct 10. Referring to Fig. 13, the third support 23 can extend from the stern protrusion S in the lower (6 o'clock direction) or upward (12 o'clock direction) of the ship. The third support bar 23 also connects the stern protrusion S and the duct 10 in the same manner as the first support bar 21 and the second support bar 22 so that the position of the duct 10 can be relatively fixed. When the duct 10 and the stern protrusion S are connected using the first support 21, the second support 22 and the third support 23, the duct 10 can be supported more stably have.

However, since the third support 23 is disposed inside the duct 10, it can act as a resistance to obstruct the flow of the fluid flowing into the duct 10. According to one embodiment, the third support 23 may have a streamlined plate shape. That is to say each longitudinal section of the second support 22 may have the form of a streamlined airfoil. With this configuration, it is possible to minimize an increase in resistance due to the third support 23.

FIG. 14 is a diagram comparing v-w velocity vector fields of a fluid in a yz section of a duct-type ship energy saving apparatus according to an embodiment of the present invention. Fig. 14 (b) shows a state in which the supporter is attached at 0, Fig. 14 (c) shows a state in which the supports of the port / starboard are rotated so as to have an angle in the opposite direction (D) shows an embodiment of the present invention. It can be seen that the shape of the flow field passing through the duct changes according to each state.

15 is a diagram illustrating a change in the v-w velocity vector field of a fluid at the yz cross section of a propeller when a duct-type ship energy saving device according to an embodiment of the present invention is installed on a ship. Fig. 15 (a) is a bare hull state, and Fig. 15 (b) is a state in which a duct-type ship energy saving device according to an embodiment of the present invention is installed on a ship. (a), the flow of the fluid passing through the propeller is formed disadvantageously at the port side, similarly to (c) of FIG. (b), similar to FIG. 1 (b), it can be seen that the flow of fluid passing through the propeller is changed to rotate counterclockwise as a whole and becomes closer to the ideal shape. That is, the second support 22 and the pin 30, which are disposed on the second hinge side and have a positive average slope, change the flow of the fluid on the port side in which the flow field is unfavorably changed from the ascending flow to the descending flow, The propulsion efficiency of the propeller is improved by rotating the fluid in the direction opposite to the propeller rotation.

The present inventor has found that the average inclination of the first support 21 and the second support 22 in the state where both the third support 23 and the pin 30 are in contact with the Korean Marine Science and Technology Laboratory's vessel and marine plant laboratory (KRISO) And the model experiment was carried out. At this time, the slopes of the first stage 21-1 and the second stage 21-2 of the first support 21 have an angle of 10 ° and -10 ° with the average slope of the first support.

Table 1 below shows the relationship between the average inclination (angle) of the starboard first supporting frame 21 and the average inclination (angle) of the second supporting frame 22 on the port side in relation to the bare hull state Represents the amount of reduction of the horsepower (DHP-delivery horse power).

우현좌현Starboard star	-10°-10 °	-5°-5 °	0°0
20°20 °	-3.22%-3.22%	-3.11%-3.11%	-3.39%-3.39%
15°15 °	-3.22%-3.22%	-3.66%-3.66%	-3.11%-3.11%

When the duct-type ship energy saving device according to the embodiment of the present invention is installed, the average tilt change (angle change) of the first support table 21 and the second support table 22 is about 3.3% , And a maximum horsepower reduction of about 3.7%.

According to the duct-type ship energy saving apparatus according to the embodiment of the present invention, the stagnation phenomenon of the fluid at the stern protruding portion (S) side by the first support base (21) disposed on the starboard and bent at opposite ends in opposite directions Can be minimized and the increase in the excessive resistance acting on the ship can be reduced.

In the present specification, it is assumed that the propeller rotates in the clockwise direction, and the first side on which the first support is disposed is assumed to be the starboard. However, it is needless to say that the principle of the present invention can be applied to the case where the propeller is rotated in the counterclockwise direction and the above description is symmetrical.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

Claims

A duct disposed in a shape surrounding a part of the stern projection of the ship; And

And a support connecting the stern protrusion to an inner surface of the duct,

The support portion

And a first support disposed at a first side of the ship, the first end connected to the stern protrusion and the second end connected to the inner surface of the duct being bent in directions opposite to each other.
The method according to claim 1,

Wherein the inclination of the first end with respect to the propelling shaft is greater than the inclination of the second end with respect to the propelling shaft.
3. The method of claim 2,

Wherein the inclination of the first support decreases from the first end to the second end.
The method according to claim 1,

The support portion

And a second support disposed at a second proximal side of the vessel and having a positive average slope with respect to the propulsion shaft of the vessel.
The method according to claim 1,

A second hinge disposed on the second hinge side of the ship,

Further comprising: a plurality of fins protruding from an inner surface of the duct toward the center axis of the duct.
6. The duct-type energy saving device according to claim 5, wherein the fins disposed on the relatively upper side of the plurality of fins have a larger average slope than the fins disposed on the lower side.
The method according to claim 1,

Wherein the support portion is formed symmetrically with respect to a central vertical cross-section of the ship,

Further comprising a third support connected to the stern protrusion and the inner surface of the duct.