WO2019194350A1

WO2019194350A1 - Propeller for ship

Info

Publication number: WO2019194350A1
Application number: PCT/KR2018/005374
Authority: WO
Inventors: 이승호
Original assignee: 필드지 주식회사
Priority date: 2018-04-03
Filing date: 2018-05-10
Publication date: 2019-10-10
Also published as: KR20190115719A; KR102150102B1

Abstract

A propeller for a ship according to an embodiment of the present invention comprises: a hub; a blade protruding in a radial direction from the hub; and a fin protruding from the edge of the blade.

Description

Marine propeller

Embodiments of the present invention relate to propellers used in ships.

In general, a ship is provided with a propeller receiving the driving force generated from the engine. When the propeller rotates, the pressure difference generated before and after the blade of the propeller generates the thrust required to propel the ship.

At this time, a vortex occurs in the edge portion of the propeller blade when the propeller rotates. These vortices cause the propeller to reduce thrust.

Accordingly, in the related art, in order to improve propulsion efficiency of the propeller, a configuration of suppressing eddy currents by providing an additional fin to the tip of the propeller blade has been proposed. There is a problem that the efficiency is reduced by the movement of the forward ratio due to the change in length. On the other hand, a configuration for attaching a plate surrounding the pressure surface and the suction surface at the propeller tip portion has been proposed, but it is known that there is a problem that cavitation occurs in the suction surface.

One object of the present invention is to provide a ship propeller and a propeller design method for increasing the propeller's sole efficiency while minimizing the increase in resistance caused by the pins connected / attached to the propeller. However, these problems are exemplary, and the scope of the present invention is not limited thereby.

Ship propeller according to an embodiment of the present invention, the hub; A blade protruding from the hub in a radial direction; And a fin protruding from an edge of the blade.

According to one embodiment, the pin may protrude toward any one of the pressure surface or the suction surface of the blade.

According to an embodiment of the present disclosure, the blade may have a sharp point in which a slope is bent in front of the blade, and the pin may extend from the tip of the blade to the sharp point.

According to one embodiment, the pin may extend from the tip of the blade to the point where the blade and the hub meet.

According to one embodiment, the fins are the edges when simulating the flow field of fluid flowing around the blades, assuming that the blades operate at a vessel running at a design speed before the fins are placed on the blades. In the region parallel to the central axis of the hub can be arranged in a region where the flow velocity of the fluid is zero (or sufficiently close to zero).

According to an aspect of the present invention, there is provided a method of designing a propeller for a ship, comprising the steps of: i) assuming that the propeller operates on a ship moving at a design speed, firstly simulating a flow field of fluid flowing around a blade; ii) simulated In the flow field, calculating an optimum region in which the x-direction velocity of the fluid at the edge of the blade is zero, iii) placing the fin in the optimal region, and then performing a second simulation to simulate 1 comparing with the results of the simulation.

According to one embodiment of the present invention, in a trade-off relationship between damage by a pin and gain due to an increase in thrust and a resistance by a pin at a given rotation speed, it is possible to increase the propeller's sole efficiency. The optimal position, width and length of the pin can be derived. More specifically, it is possible to increase the propeller's sole efficiency while minimizing the pin's own resistance by attaching / connecting / positioning the pin only in the area where the vortex is generated in the blade.

1 is a perspective view showing a ship propeller according to an embodiment of the present invention, Figure 2 is a cross-sectional view taken along the line II-II 'propeller of FIG.

3 and 4 are front views of propellers including blades each having a different shape.

5 shows the flow rate and streamline in the propeller before attaching the pin to the blade.

Figure 6 shows the flow rate and streamline in the propeller after the pins are attached to the blades.

Figure 7 shows the flow field around the blade before and after attaching the pin to the blade.

8 is a perspective view showing a ship propeller according to another embodiment of the present invention, Figure 9 is a view showing a front view, a top view, a right side view of the propeller of FIG.

10 is a cross-sectional view of the propeller cut into propellers and several planes perpendicular to the x-axis before the pin is attached.

FIG. 11 is a diagram simulating the velocity of a fluid in the plane P1 to P5 of FIG. 10.

12 shows the propeller after the pin is attached.

13 is a simulated streamline around the blade before and after attaching the pin to the blade.

As the inventive concept allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail. Effects and features of the present invention, and methods of achieving them will be apparent with reference to the embodiments described below in detail with reference to the drawings. However, the present invention is not limited to the embodiments disclosed 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 component from other components rather than having a limiting meaning.

In the following embodiments, the singular forms “a”, “an” and “the” include plural forms unless the context clearly indicates otherwise.

In the following embodiments, terms such as include or have means that the features or components described in the specification are present, and does not preclude the possibility of adding one or more other features or components.

In the case where an embodiment may be implemented differently, specific steps may be performed out of the order described. For example, two steps described in succession may be performed substantially concurrently, or may be performed in a reverse order.

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

In the present specification, the x axis is the axis passing through the ship's bow and stern, the y axis is the axis passing through the ship's port and starboard, and the z axis is the axis passing through the ship's bottom and upper deck.

In the present specification, the design speed means a speed that can be achieved at 85% or 90% of the maximum power of the main engine mounted on the ship, and the speed that the shipyard must satisfy as a contract condition in the ship construction contract. .

In the present specification, 'simulation' may include computer simulation using computational fluid dynamics (CFD) or model simulation using a model ship. In this case, the speed of the fluid and the shape of the stream line derived through the simulation may be different depending on the shape of the propeller and the design speed (or the speed of the fluid passing around the ship). However, when the shape and design speed of the propellers are fixed, the speed of the fluid and the shape of the streamline around the propellers can be clearly defined through simulation.

1 is a perspective view showing a ship propeller 10 according to an embodiment of the present invention, Figure 2 is a cross-sectional view taken along the line II-II 'propeller 10 of FIG.

Ship propeller 10 according to an embodiment of the present invention, includes a hub 110, a blade 120, a pin 130. Referring to FIG. 1, the hub 110 is disposed at the center of the propeller 10. The hub 110 may be connected to a drive shaft (not shown) for transmitting kinetic energy of the engine and rotate about the x axis.

The plurality of blades 120 may be connected to the hub 110. The blade 120 protrudes from the hub 110 in the radial direction. When the hub 110 rotates, the blade 120 may also rotate about the x axis. The z-axis vertical cross section of the blade 120 may be streamlined. The blade 120 may be divided into a pressure surface 120PS and a suction surface 120SS with a thinly formed edge. The edge of the blade 120 may be divided into a leading edge 120LE and a trailing edge 120TE with the tip 120T farthest from the hub 110. Due to the pressure difference between the fluid passing through the pressure surface 120PS of the blade 120 and the fluid passing through the suction surface 120SS, the blade 120 faces the suction surface 120SS from the pressure surface 120PS. force in the -x direction).

Outside of the propeller 10, the fluid flowing in the x direction toward the propeller 10 is converted into a rotational flow due to the rotation of the propeller 10. This rotational flow generates a vortex. Vortex causes a reduction in thrust by the propeller 10.

In order to solve this problem, the ship propeller 10 according to an embodiment of the present invention includes a pin 130 protruding from the edge of the blade (120). The pin 130 may protrude toward either the pressure surface 120PS or the suction surface 120SS of the blade 120, but in the following, the pin 130 may face the pressure surface 120PS of the blade 120. The protrusion will be described mainly. Referring to the enlarged picture of FIG. 2, the cross section of the fin 130 may be a triangle, but the present invention is not limited thereto. In cross section, an angle formed between the edge of the pin 130 and the blade 120 may be 90 degrees or more.

The fin 130 serves to reduce vortex occurring near the edge of the blade 120. Accordingly, the propeller 10 is able to produce a higher thrust. However, the pin 130 acts as a resistance by itself, and if the size and length are excessively increased or the wrong position is selected, the pin 130 increases resistance and torque to reduce the efficiency of the propeller 10. Therefore, in order to increase the efficiency of the propeller 10, it is important to properly attach and design the position and length rather than attaching the pin 130 to the entire edge of the blade 120.

3 and 4 are front views of propellers 10 including blades 120 having different shapes, respectively.

According to one embodiment, the pin 130 may be disposed in front of the blade 120 (120LE).

According to one embodiment, the blade 120 has a sharp point (120SP) in which the inclination is bent at the leading edge (120LE), the pin 130 is extended from the tip (120T) of the blade 120 to the point (120SP) Can be. The tip 120T refers to the point farthest from the hub 110 in the blade 120. Meanwhile, referring to FIG. 3, in the high-speed rotating propeller 10, there may be a sharp point 120SP in which the inclination of the front edge 120LE of the blade 120 is sharply bent. In this case, the pin 130 is the tip 120T. ) May extend from the point to 120SP.

According to one embodiment, the pin 130 may extend from the tip 120T to the point where the blade 120 and the hub 110 meet. Referring to FIG. 4, the blade 120 may have a smooth shape without a sharp bending point. In this case, the pin 130 may extend from the tip 120T to the outer surface of the hub 110.

The inventors have found that when the fin 130 is positioned as described above at the end of a number of experiments, the efficiency of various types of high speed propeller 10 used at 1000 rpm or more can be increased on average. Furthermore, the present inventors have found a method of determining the position of the pin 130 to achieve optimum efficiency for each of the high speed rotation propellers 10 having different shapes and sizes, which will be described below.

The location of the fin 130 can be designed / determined after simulating the flow field around the blade 120 before the fin 130 is attached / connected to the blade 120.

According to one embodiment, the fin 130 simulates the flow field of the fluid flowing around the blade 120 assuming that the propeller 10 operates on a ship moving at a design speed without the fin 130. At this time, the flow rate of the fluid in the direction parallel to the central axis of the hub 110 at the edge of the blade 120 may be disposed along the point of zero.

5 is a diagram illustrating the velocity distribution and the streamline on the surface of the propeller 10 'before attaching the fin 130 to the blade 120. FIG. In the following figures, where the concentration is indicated (center and back front of the blade) is a reference where the relative velocity of the fluid is one. In the following figures, the bright area (white area) near the front of the propeller indicates an area where the axial velocity is close to zero. In other words, the speed component in the axial direction is changed to the speed component in the rotation direction.

Referring to the left figure of FIG. 5, there is an area of zero flow velocity on the front edge 120LE of the blade 120. This region is a region where the fluid is stagnant or a vortex occurs, which causes the thrust of the propeller 10 to be reduced. Referring to the right figure of FIG. 5, it can be seen that the streamline is particularly twisted at the leading edge 120LE of the edge of the blade 120 before the pin 130 is attached.

In one embodiment of the present invention, after simulating the flow field around the propeller 10 ′ in the absence of the fin 130, the fin 130 in the region where the velocity of the fluid in the x direction is zero at the edge of the blade 120. ). That is, in the propeller 10 ′ of FIG. 5, the fin 130 may be disposed perpendicularly to the pressure surface 120PS at a position corresponding to the front front of the blade 120.

On the other hand, the region in which the velocity in the x direction of the fluid is zero does not mean a region in which the velocity is completely zero, but is preferably understood to be a region sufficiently close to zero. For example, the region in which the velocity of the fluid in the x direction is 0 may refer to a region having a velocity of about 0 to 10% based on the velocity in the reference region in which the relative velocity of the fluid is 1.

FIG. 6 shows the flow rate and streamline in the propeller 10 after the fin 130 is attached to the blade 120.

Referring to the left figure of FIG. 6, compared with the left figure of FIG. 5, the bright region (white region) is widened so that the low velocity region is increased, but the region having zero flow velocity is almost disappeared. In addition, referring to the right picture of FIG. 6, it can be seen that the streamline at the front row 120LE is simplified after attaching the pin 130 as compared with the right picture of FIG. 5.

7 shows the flow field around the blades 120 before and after attaching the fins 130 to the blades 120. The figure located in column (a) of FIG. 7 shows the flow rates in several cross sections perpendicular to the x-axis before the pin 130 is attached to the blade 120. At this time, referring to the box area of each figure, it can be seen that a region having a high concentration of zero flow velocity is formed in the vicinity of each of the cross section perpendicular to the axis and the blade 120.

In an embodiment of the present invention, the point where the velocity of the fluid in the x-axis direction is zero at the point where the blade 120 meets the cross section perpendicular to the x-axis is calculated. Subsequently, while changing the position of the cross section perpendicular to the x-axis, the 'section' in which the velocity of the fluid in the x-axis direction is zero at the edge of the blade 120 is calculated. The 'section' is then determined as the region where the pin 130 is to be located.

The figure located in column (b) of FIG. 7 shows the flow rates in several cross sections perpendicular to the x-axis after the pin 130 is attached to the blade 120. Referring to the box area of each figure, it can be seen that the size of the region with the deep concentration formed near the point where each cross section and the blade 120 meet is smaller than the column (a). The attachment of the fin 130 prevents the movement of the fluid from the high pressure to the low pressure, thereby reducing the occurrence of the rotational flow generated thereby increasing the axial velocity component.

Table 1 below shows the difference in thrust, torque and efficiency of the propeller 10 according to an embodiment before and after the pin 130 is attached. In one experimental example, the rpm of the propeller 10 on the simulation was 3000 and the speed of the fluid to set the Froude number was 10 m / s. The diameter of the propeller 80 was 0.38 m.

	추력(Thrust)Thrust		토크(torque)Torque		단독효율(η_o)Independent efficiency (η _o )
핀 없음No pins	13869.3[N]13869.3 [N]	차이(Difference( %% ))	968.4[Nm]968.4 [Nm]	차이(%)Difference(%)	0.4560.456	차이(%)Difference(%)
핀 부착With pin	13512.5[N]13512.5 [N]	-2.6-2.6	906.3[Nm]906.3 [Nm]	-6.4-6.4	0.4750.475	4.24.2

Referring to the above [Table 1], in the high speed rotation propeller, both the thrust and the torque after the pin 130 is attached. However, the reduction ratio of the torque is greater than the reduction ratio of the thrust, it can be seen that the propeller 10 alone efficiency ( _o ) of the propeller 10 after attachment is increased by 4.2% compared to the propeller 10 'before attachment. That is, when the pin 130 is attached to the position derived in the same manner as described above, it is possible to improve the overall efficiency of the propeller 10 by changing the flow field while minimizing the increase in resistance.

8 is a perspective view showing a ship propeller 80 according to another embodiment of the present invention, Figure 9 is a view showing a front view, a top view, a right side view of the propeller 80 of FIG.

According to an embodiment of the present disclosure, the blade 820 may have a relatively flat area between the front edge 820LE and the rear edge 820TE. Fins 830 may be disposed in all or part of these flat areas.

The inventors have found that, after numerous experiments, placing the pin 830 as described above can increase the average efficiency of the various low speed propellers 80 used at 1000 rpm or less. Furthermore, the inventors have found a method of determining the position of the pin 830 for optimum efficiency for each low speed rotation propeller 80 having different shapes and sizes, which will be described below.

The location of the pin 830 can be designed / determined after simulating the flow field around the blade 820 before the pin 830 is attached / connected to the blade 820.

According to one embodiment, the fin 830 simulates the flow field of fluid flowing around the blade 820 assuming that the propeller 80 operates at a vessel maneuvering at a design speed without the pin 830. At this time, the flow rate of the fluid in a direction parallel to the central axis of the hub 810 at the edge of the blade 820 may be disposed along the zero point.

10 is a cross-sectional view of the propeller 80 and the propeller 80 cut into several planes perpendicular to the x-axis before the pin 830 is attached.

Referring to FIG. 10, a plurality of planes P1 to P5 perpendicular to the x axis are shown in the virtual duct D surrounding the propeller 80, and each plane P1 to P5 is formed of the blade 820. The points that meet the edge are marked 820P1 ~ 820P5, respectively.

In one embodiment of the present invention, while calculating the velocity of the fluid in each plane while moving the plane perpendicular to the x-axis along the x direction, and find the point or area where the velocity of the fluid in the x direction is zero.

Referring to FIG. 11, an area where the x-axis velocity is zero is not observed near the intersection 820P1 of the blade 820 and the P1 plane and the intersection 820P2 of the blade 820 and the P2 plane. However, in the P3 plane, a region with a high concentration of zero flow velocity begins to be observed in the square box region near the intersection 820P3 of the blade 820 and the P3 plane. In the P4 and P5 planes, a region with a high concentration of zero flow velocity is clearly seen in the box area near the intersections 820P4 and 820P5 of the blade 820 and the P4 and P5 planes. That is, the points 820P1 and 820P2 do not start to generate vortices because the velocity of the fluid is not zero, and the points 820P3, 820P4 and 820P5 begin to generate vortices because the velocity of the fluid is zero. That is, in the blade 820 having the shape of FIG. 10, it can be seen that the section from the point 820P3 to the point 820P5 is an area in which the vortex is generated as the section in which the x-axis flow velocity is zero. Although the cross section is illustrated as five above, when the number of cross sections is increased by making the gap between the cross sections small enough, it is possible to accurately grasp the range of the region where the flow velocity is 0 at the boundary of the blade 820.

12 shows the propeller 80 after the pin 830 is attached.

10 to 12, the pin 830 is disposed only at the point where the x-axis flow rate is zero among the points where the plane and the edge of the blade 820 meet. That is, the pin 830 may not be attached to the entire edge of the blade 820, but may be attached to a portion of the edge of the blade 820, in particular, a section having an x-axis flow rate of zero based on a simulation result.

FIG. 13 is a simulated streamline around blade 820 before and after attaching pin 830 to blade 820. Figure 13 (a) shows the streamline near the tip 820T of the blade 820 before attaching the pin 830 to the blade 820, and the illustration in column (b) shows the pin ( 830 is attached to blade 820 and shows a streamline near tip 820T of blade 820. Comparing (a) and (b), the size of the region where the axial velocity component is zero is reduced by the pin 830. This results in almost no rotational flow.

[Table 2] below shows the difference between the thrust, torque and efficiency before and after the pin 830 attached to the propeller 80 according to an embodiment of the present invention. In one experimental example, the rpm of the propeller 80 on the simulation was 500 and the speed of the fluid for setting the Froude number was 2 m / s. The diameter of the propeller 80 was 0.26 m.

	추력(Thrust)Thrust		토크(torque)Torque		단독효율(η_o)Independent efficiency (η _o )
핀 없음No pins	22.4443[N]22.4443 [N]	차이(%)Difference(%)	0.8844[Nm]0.8844 [Nm]	차이(%)Difference(%)	0.50480.5048	차이(%)Difference(%)
핀 부착With pin	23.4999[N]23.4999 [N]	4.704.70	0.9135[Nm]0.9135 [Nm]	3.283.28	0.51120.5112	1.381.38

Referring to the above [Table 2], in the low speed rotation propeller, both the thrust and the torque increased after the pin 830 was attached. However, the increase rate of the torque is smaller than the increase rate of the thrust, it can be seen that the single efficiency ( _o ) of the propeller 80 after the pin 830 attached increased 1.38% compared to the propeller 10 'before the attachment. That is, when the pin 830 is attached to the position derived in the same manner as described above, the overall efficiency of the propeller 80 may be improved by changing the flow field while minimizing the increase in resistance.

Unlike one embodiment of the present invention, if the pin is designed to be unnecessarily long and large, the thrust is increased but the torque is also increased to lower the propeller alone efficiency.

The above-described method of optimal positioning of the pin can be used when attaching the pin to the already manufactured propeller to improve efficiency or design a new propeller.

According to an embodiment of the present invention, a method of designing a propeller for a ship includes: i) a first simulation of a flow field of a fluid flowing around a blade, assuming that the propeller operates in a ship moving at a design speed, ii) in a simulated flow field, Calculating an optimal region in which the x-direction velocity of the fluid at the edge of the blade is zero, iii) placing the fin in the optimal region, and secondly simulating the flow field of the fluid flowing around the blade to which the fin is attached. Comparing with results.

If the propeller is designed in the same manner as described above, the pin-off can increase the propeller's sole efficiency in a trade-off relationship between the resistance caused by the pin and the damage caused by the increase in torque and the gain due to the increase in thrust. The optimal position and length can be derived. More specifically, according to the present invention, by attaching / connecting / arranging pins only to areas where vortices are generated in the blades, it is possible to increase propeller alone efficiency while minimizing pin self-resistance.

On the other hand, in the above embodiment has been illustrated that one pin is disposed on the blade, but the present invention is not limited thereto. When there are a plurality of regions in which the x-direction velocity of the fluid is zero at the edge of the blade, a plurality of pins may also be arranged.

Although the present invention has been described with reference to the embodiments illustrated in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims

Herb;

A blade protruding from the hub in a radial direction;

And a fin protruding from the edge of the blade.
The method of claim 1,

And the pin protrudes toward either the pressure side or the suction side of the blade.
The method of claim 1,

The blade,

Has a point of inclination of the blade in front of the blade,

The pin,

A propeller for ships extending from the tip of the blade to the point.
The method of claim 1,

The pin,

A propeller for ships extending from the tip of the blade to the point where the blade and the hub meet.
The method of claim 1,

The blade has a flat area between the leading and trailing edge,

Wherein the pin is disposed in all or part of the flat area.
The method of claim 1,

The pin,

A direction parallel to the central axis of the hub at the edge when simulating the flow field of fluid flowing around the blade, assuming that the blade operates in a ship moving at a design speed before the pin is placed on the blade A propeller for ships, disposed in an area where the flow velocity of the fluid to zero is zero.