WO2014178685A1

WO2014178685A1 - Device for controlling flow of open shaft ship

Info

Publication number: WO2014178685A1
Application number: PCT/KR2014/003958
Authority: WO
Inventors: 김정중; 한재문; 이경준; 김진학; 이진석; 문종태; 정재권; 이정훈; 김진규
Original assignee: 삼성중공업 주식회사
Priority date: 2013-05-03
Filing date: 2014-05-02
Publication date: 2014-11-06
Also published as: KR101525791B1; KR20140131086A

Abstract

A device for controlling the flow of an open shaft ship is provided. A device for controlling the flow of an open shaft ship according to an embodiment of the present invention comprises: a thrust shaft member exposed to the outside towards the rear of the ship; a propeller hub rotatably coupled to the thrust shaft member; a propeller wing positioned on the outer surface of the propeller hub; and a flow control member arranged in front of the propeller wing with reference to the forward moving direction of the ship, wherein the flow control member comprises a plurality of base units protruding from the circumference of the thrust shaft member at a distance from each other and a connection unit for connecting the plurality of base units.

Description

【Specification】

[Name of invention]

Flow control device of open shaft ship 【Technical field】

The present invention relates to a flow control device for a ship, and more particularly, to a flow control device for an open shaft ship.

Background Art

In recent years, the cavitation of the propeller, that is, the vibration noise phenomenon has emerged as a new problem as the size and speed of the ship have increased.

This cavitation phenomenon does not occur at the propeller blades when the ship is operating at low speed, but if the propeller wing stroke speed is increased to increase the speed of the ship, the pressure on the surface of the propeller blades is lowered and occurs at a certain speed. This is called the Cavitation Inception Speed (CIS), and the occurrence of cavitation greatly increases the likelihood of noise, vibration, and propeller wing erosion. This cavitation phenomenon occurs when the pressure around the propeller blades drops rapidly and falls below the saturated steam pressure, causing the fluid around the propellers to vaporize.

Basically, propulsion by propeller of ship is thrust through pressure difference between pressure-side and suction-side of propeller blade generated by propeller rotation. In addition, increasing the speed of the ship means that the propeller rotation speed is increased to increase the pressure difference between the propeller pressure surface and the suction surface, so that the cavitation generation due to the pressure drop of the suction surface is necessarily accompanied by the high speed operation. .

On the other hand, among the various ships, because the nature of the ship to lower the likelihood of detection, while ensuring the maneuverability, the initial cavitation speed may be a more important performance indicator. Cavitation does not occur because the underwater noise is rapidly increased from the point of cavitation and the probability of detection is increased. The highest operating speed within range is indispensable. Therefore, in general, when designing a propeller for a ship, the cavitation initial speed is mainly considered. However, as described above, it is not easy to increase the cavitation start-up speed because the increase in speed involves cavitation occurrence.

Most warships are open-shaft vessels. In the case of such an open shaft vessel, the propulsion shaft and the supporting column fixing the propulsion shaft are exposed to the outside of the hull, and in general, the propulsion shaft for rotating the propeller is inclined relative to the horizontal plane. The inclination of the propulsion shaft and the exposed support column determine the characteristics of the flow, that is, the inflow, into the propeller plane.

Due to the characteristics of the inflow, the angle of attack or angle of attack based on the propeller blade cross-section at the propeller blade's boundary between the propeller blade and the propeller blade for securing the propeller blade to the propulsion shaft (AOA) ) Has a much larger change during propeller rotation than the cross section at the wing tip in the radial direction of the propeller, so that during one revolution of the propeller wing, the propeller wing suction surface at a specific propeller wing angle position area at the boundary of the propeller wing with the propeller hub The pressure of the pressure surface is lower than the pressure surface, and in another specific propeller wing angle position region, the pressure on the pressure surface is lower than the pressure on the suction surface. On the pressure side The probability of occurrence of cavitation increases at the same time.

Thus, in general, the cross-sectional pitch and camber setting of the propeller blades at the boundary of the ship's propeller blades are focused on a portion that properly balances the occurrence of cavitation between the suction and pressure surfaces rather than the thrust generation. That is, if the propeller blade shape is designed to increase the cavitation regeneration speed of the suction surface, the cavitation regeneration speed of the pressure surface is lowered, and if the propeller wing shape is designed to increase the cavitation regeneration speed of the pressure surface, the cavitation regeneration of the suction surface In the opposing relationship of slow speed, the propeller inflow flow distribution boundary pressure with the propeller hub at the propeller blades is determined by the shape design deformation only when the propeller inflow flow distribution characteristics are determined by factors such as linear and propeller front shaft support structure and propulsion inclination. It is not possible to increase both the cavitation initial speed of the cotton and the suction surface. [Detailed Description of the Invention]

[Technical problem]

One embodiment of the present invention is to provide a flow control device of an open shaft vessel that enables to improve the cavitation start speed when cavitation begins to occur.

Technical Solution

In accordance with an aspect of the present invention, the flow control device of the open shaft ship is a propeller shaft which is exposed to the outside toward the rear of the vessel, the propeller hub rotatably coupled to the propeller shaft member, the propeller located on the outer surface of the propeller hub And a flow control member disposed in front of the propeller blade based on a wing and a direction in which the vessel is advanced, wherein the flow control member includes: a plurality of base portions protruding from the periphery of the propulsion shaft member and spaced apart from each other; It may include a connecting portion for connecting the plurality of base parts.

In this case, the plurality of base parts and the connection part may be integrally formed.

In this case, the connection part may be formed to be bent to protrude in a direction away from the propulsion shaft member.

In this case, the base section may have a hydrofoil sect ion.

In this case, the flow control member may be formed in a region in which the angle of attack (AOA) of the propeller blade becomes a negative value on the circumferential surface of the propulsion shaft member.

At this time, the flow control member may be formed in the vicinity of the lowest angle of attack (AOA) of the propeller blades on the circumferential surface of the propulsion shaft member. At this time, the two base parts are formed, and the two base parts are formed such that the point at which the angle of attack (AOA) of the propeller blade becomes the minimum value on the circumferential surface of the propulsion shaft member is located between the two base parts. Can be. In this case, the angle of attack may be the angle of attack at the cross section of the boundary portion of the propeller blade and the propeller hub. In this case, each of the plurality of base parts may be spaced apart from each other at regular intervals.

In this case, the connection unit may connect ends of each of the base units. Advantageous Effects

In the flow control apparatus of the open shaft ship according to an embodiment of the present invention, the flow angle in the rotational direction angle position is minimized by the propeller inflow characteristic and the angle of attack determined by the cross-sectional reference pitch angle setting of the boundary between the propeller blade and the propeller hub The control unit is installed. Accordingly, in the angle of attack graph, the negative peak value is relatively increased, so that the minimum pressure value is increased when the reference pressure change of the pressure surface of the propeller blade section is increased compared to the case without the flow control device. The probability of occurrence of cavitation can be reduced. This allows the cavitation velocities of the cross-sectional reference pressure surface at the boundary of the propeller blades and propeller hub to be improved without a reduction in the same part suction surface cavitation velocities.

In addition, in the flow control device of the open shaft ship according to the present invention, the flow control member is formed in a shape in which the ends of the plurality of base parts are connected by the connecting portion. Accordingly, by suppressing the generation of vortex at the end of the base portion, it is possible to prevent the phenomenon that such vortex flows into the propeller blades and additionally cavitation occurs.

[Brief Description of Drawings]

1 is a perspective view showing a state in which the lighting control device of the open shaft ship according to an embodiment of the present invention is installed on the ship.

Figure 2 is a perspective view showing only the flow control member of the flow control device of the open shaft ship according to another embodiment of the present invention.

3 is an enlarged view of a portion in which the flow control device is installed in the open shaft vessel shown in FIG. 1.

4 is a cross-sectional reference angle of attack between the propeller blades and the propeller hub in the vessel with and without the flow control device according to the present invention. It is a graph measured.

5 is a flow field graph of the propeller blade surface in the vessel with and without the flow control device according to the present invention. <Explanation of Codes>

10: ship 20: support

100 ： flow control device of open shaft ship

110: propulsion shaft member 120: propeller blade

121: propeller hub 130: flow control member

131 ： base portion 132: connecting portion

[Best form for implementation of the invention]

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like elements throughout the specification.

Throughout the specification, when a part is said to "include" a certain component, it means that it may further include other components, except to exclude other components unless otherwise stated.

1 is a perspective view showing a state in which a flow control device of an open shaft ship according to an embodiment of the present invention is installed on the ship.

Referring to FIG. 1, a flow control apparatus of an open shaft vessel according to an embodiment of the present invention includes a propulsion shaft member 110, a propeller hub 121, a propeller blade 120, and a flow control member 130. It may include.

The propulsion shaft member 110 may be exposed to the outside from the bottom of the vessel 10 toward the rear of the vessel 10. The propulsion shaft member 110 may be fixed by the support 20 formed on the bottom of the vessel 10, but is not limited thereto.

The propeller hub 121 is rotatably coupled to the propulsion shaft member 110. The propeller blades 120 are located on the outer surface of the propeller hub 121. That is, the propeller blades 120 may be rotated at the end of the propulsion shaft member 110.

Power generated from the power source inside the vessel 10 is transmitted to the propulsion shaft member 110, the propeller blades 120 can be rotated by this power.

Flow control member 130 serves to reduce the probability of cavitation in the pressure surface of the cross section of the boundary portion with the propeller hub 121 in the propeller blade (120). Flow control member 130 for this may be disposed in front of the propeller blades 120 on the basis of the direction in which the ship 10 is advanced. By the flow control member 130, the deviation of the angle of attack (AOA) of the propeller blades 120 can be reduced. This angle of attack is the angle of attack for the cross section of the boundary of the propeller blades 120 and the propeller blade hub 121. Therefore, the deviation of the angle of attack of the cross section of the boundary portion with the propeller hub 121 in the propeller blade 120 can be reduced. Hereinafter, the 'boundary portion of the propeller blade 120 and the propeller hub 121' will be described as being defined as the 'root portion of the propeller blade 120'. Accordingly, the pressure in the pressure surface of the cross section at the root portion of the propeller blade 120 is relatively high, so that the flow control member 130 is installed at a specific position of the propulsion shaft member 110 to suppress the occurrence of cavitation. Play a role. To this end, the flow control member 130 includes a plurality of base parts 131 and the connection part 132.

The plurality of base parts 131 are formed to protrude from the circumference of the propulsion shaft member 110. For example, as shown in FIG. 1, the plurality of base portions 131 may be formed to protrude in a radial direction of the propulsion shaft member 110 having a circular cross section, and extend in the longitudinal direction of the propulsion shaft member 110. It may be formed in the form.

The plurality of base parts 131 are formed to be spaced apart from each other. Each of the plurality of base parts 131 may be formed to have a different shape such as length or thickness according to the design. Each of the plurality of base parts 131 may be spaced apart from each other at regular intervals. That is, the plurality of base parts 131 may be two or more. The shape of the plurality of base portions 131 may be contoured to, for example, a hydrofoil section. The hydrofoil is a curved shape of the front part in order to minimize the resistance of water or air, and the pointed shape toward the rear of the hydrofoil, the flow control member 130 can be made in the shape of a hydrofoil. have.

The connecting portion 132 connects the ends of the base portions 131. The material of the connection part 132 may be the same as the material of the base part 131. Alternatively, the material of the connecting portion 132 may be different from the material of the base portion 131. However, the same material of the connecting portion 132 and the base portion 131 may be advantageous in easily connecting the connecting portion 132 and the base portion 131 by a welding method. The connecting portion 132 connects ends of each of the plurality of base portions 131.

This connecting portion 132 prevents the cavitation generated by the vortex that may occur at the end of the base portion 131.

Unlike the above-described structure, when the flow control member 130 does not include the connecting portion 132 and consists only of the base portion 131, a vortex may be generated at the tip of the base portion 131. have. However, in the flow control apparatus of the open shaft ship according to the present invention, the flow control member 130 has a shape in which the ends of the plurality of base parts 131 are connected by the connection part 132. As a result, it is possible to suppress the occurrence of vortex at the end of the base portion 131.

In more detail, the cavitation caused by the vortex that may occur at the end of the base portion 131 may be very sensitive to the flow incident angle flowing into the base portion 131. In actual operation of the vessel, the flow incident angle flowing into the base portion 131 is changed in an environment such as when the odd value of the odd number of the vessel temporarily changes, so that the cavitation caused by the vortex at the end of the base portion 131 is changed. There is a possibility.

In addition, even if the vortex does not change in the form of cavitation at the end of the base portion 131, if the vortex strength is strong, the vortex may flow into the propeller blades. At this time, the vortex may develop into cavitation due to the low pressure of the flow around the leading edge of the propeller blades. Therefore, it is also important to suppress the generation of vortex at the end of the base portion 131 or to minimize the strength of the vortex.

On the other hand, it will be described later that the cavitation initial speed is improved by the flow control member 130 included in the flow control device of the open shaft vessel 100 according to the present invention having the above-described structure. 2 is a perspective view showing only the flow control member of the flow control device of the open shaft vessel according to another embodiment of the present invention.

2, in the flow control apparatus of the open shaft ship according to another embodiment of the present invention, the base portions 231 and the connection portion 232 constituting the flow control member 230 are integrally formed. In addition, the connection part 232 may be formed to be bent to protrude in a direction away from the propulsion shaft member. In this case, the base portion 231 may be two.

Such a structure may be more durable than the flow control member 130 (see FIG. 1) included in the flow control apparatus of the open shaft ship according to the above-described embodiment. In addition, since the shape of the flow control member 230 has a curved shape, the connection portion of the base portion 231 and the connection portion 232 is smoothly formed. Accordingly, there is no angled portion in the flow control member 230 can prevent the cavitation from occurring in the flow control member 230 itself.

Figure 3 is an enlarged view showing the installation state of the flow control device of the open shaft vessel shown in FIG.

Referring to FIG. 3, the distance A from the center of the propulsion shaft member 110 to the extreme end of the flow control member 130 may be formed not to exceed 70% of the radius of the propeller blades 120. This causes cavitation in the flow control member 230 when the distance A from the center of the propulsion shaft member 110 to the extreme end of the flow control member 130 exceeds 70% of the radius of the propeller blade 120. This is because the probability can be increased.

Hereinafter, with reference to the accompanying drawings will be described a preferred installation position of the flow control member 130.

Figure 4 is a graph measuring the angle of attack of the cross section of the propeller hub in the propeller blades in the vessel with and without the flow control device according to the present invention, Figure 5 is a flow according to the present invention Flow field graph, or nominal wake distribution, on the propeller vane face on ships with and without control.

In Fig. 4, the value of the X-axis represents the angle of rotation of the propeller blade, which is set to 0 ° or 360 ° when the blade of the propeller is vertically upward, that is, at 12 o'clock in the drawing, and from the front of the ship to the rear. Based on The angle value is increased while moving clockwise. At this time, the propeller rotation direction is clockwise. As used herein, the term 'rotation direction angle value of the propeller blade' or 'propeller blade angle position' means an angle value or an angle position in the aforementioned criteria. In FIG. 4, the value of the y-axis represents the angle of attack, which is a numerical value of the angle of attack of the cross section near the root of the propeller blade 120 at the position of 30% of the radius of the propeller blade 120.

The angle of attack calculates the nominal wake on the propeller face of each of the included and uncontrolled conditions of the flow controller 130 at any same propeller rotational speed, with any cross-sectional pitch angle determined. It was calculated as a standard. Here, the angle of attack calculation is used a general angle of attack calculation method, a detailed description thereof will be omitted.

In the following, the cavitation generation when the angle of attack of the propeller blades 120 at the boundary portion with the propeller hub 121 is negative and positive is briefly described.

First, the pitch angle of the cross section at the root of the propeller blade 120, the propeller rotation speed, and the angle of attack of the cross section calculated based on the inflow flow field of the propeller blade 120 surface are positive (+). 120) This means that the pressure on the suction side of the cross section will be lower than the pressure on the pressure side, in which case cavitation may occur on the suction side.

On the contrary, a negative angle of attack of the wing section means that the pressure on the pressure side of the propeller wing is lower than the pressure on the suction side. ^this' that it may occur.

The cavitation initial velocity of the root portion of the propeller blades 120 increases as the minimum value of the angle of attack relative to the pressure plane is higher, that is, as the absolute value of the negative (-) peak is smaller, and the maximum value of the angle of attack relative to the suction plane is increased. The smaller this is, the smaller the absolute value of the positive peak increases. Therefore, the smaller the deviation between the maximum and minimum angles of the angle of attack, the faster the cavitation initial velocity of both the suction and pressure surfaces. It is advantageous.

The graph of FIG. 4 shows two angles of attack of Comparative Example (X) and Example (0), and Comparative Example (X) is the angle of attack in the structure in which the flow control member 130 is not formed. 0) is the angle of attack in the structure in which the flow control member 130 is formed. In the embodiment (0), the flow control member 130 is formed on the circumferential surface of the propulsion shaft member 110.

In the angle of attack graph of FIG. 4, that is, a section in which the X-axis value is 180 ° to 300 °, that is, the specific angle area S, the angle of attack in the structure X in which the flow control member 130 is not formed is generally It can be seen that it is a negative value.

If the angle of attack becomes negative, as described above, cavitation may occur in the pressure plane of the propeller blade cross section. Compared with the angle of attack in the structure (0) in which the flow control member 130 is formed in this region section, the angle of attack in the structure (X) in which the flow control member 130 is not formed is generally lower, that is, the sign is omitted. It is a larger value in terms of an absolute value, so that the flow control member 130 is not formed compared to the structure (0) in which the flow control member 130 is formed under the rotational speed condition of the same propeller blade 120 (X). The pressure at the front end of the propeller blades 120 at the pressure plane is lower in the above-described specific angular section, which increases the probability of cavitation in the propeller blade pressure plane and finally lowers the cavitation initial velocity of this part.

Meanwhile, in the flow control apparatus according to the present invention, the flow control member 130 may be formed in a specific angle region S of the circumferential surface of the propeller shaft member 110 in which the angle of attack of the propeller blade becomes a negative value based on the propeller rotation direction. have.

In detail, the flow control member 130 has a predetermined shape of the propeller blade 120 and the shape of a ship such as the propulsion shaft member 110, and is determined based on the cross section of the root portion of the propeller blade 120. The propulsion shaft is forward of the angle of rotation of the propeller blades 120 when the angle of attack (AOA) experienced during one revolution while rotating in the direction of rotation of the propeller blades 120 becomes a negative value. It may be formed in the region of the peripheral surface of the member (110).

In more detail, the position at which the flow control member 130 is formed is represented by the rotation direction angle value of the propeller blade 120 in the rotational surface of the propeller blade 120. It is an area | region on the circumferential surface of the propulsion shaft member 110 as a front area | region which the flow angle of attack of the root part of the propeller blade 120 becomes a negative value among the area | regions of 0 degrees-360 degrees.

At this time, the 'forward' referred to herein is defined based on the flow of the flow. That is, the flow passing through the ¹ forward 'region where the flow control member 130 is formed means that the flow angle of attack of the root portion of the propeller blades 120 passes through the region that becomes a negative value.

Therefore, for the sake of understanding, in the present specification, the position at which the flow control member ₁₃₀ is formed is defined, and the flow passing through the position of the flow control member 130 is referred to as a specific position of the propeller blade 120. Based on the time of passing, it expresses by the propeller blade | wing 120 angle position in the rotation surface of the propeller blade | wing 120.

In the case of open shaft vessels, it is common that the propulsion shaft member for rotating the propeller blades is inclined so that the rear portion of the vessel faces downward with respect to the horizontal line. Therefore, the flow into the propeller blades may contain a lot of upward velocity components relative to the propeller plane. This can also be seen from the flow field graph on the propeller blade surface when the flow control device according to the invention shown in FIG. 5 is not included, or the flow flow direction vector of the nominal wake distribution. In this case, the deviation of the angle of attack experienced during one revolution of the propeller blade relative to the root section cross-section of the propeller blade 120 may be very severe as in the case where the flow control member shown in FIG. 4 is not formed (X). Can be.

If the propeller is designed only in terms of thrust generation in the root portion of the propeller blade 120 in such a situation, the force must be generated from the pressure side to the suction side at all angular positions in the rotational direction of the propeller blade. The pitch of the propeller blade section must be reset so that the angle of attack is positive in the wing position area.

However, in this case, the flow field flowing into the propeller determined by the propeller shaft member or the propeller shaft inclination does not change, so the maximum minimum deviation of the angle of attack remains unchanged. Sharply increased and eventually the root of the propeller wing This results in a sharp decrease in the cavitation initial velocity of the suction surface. This means that when the cavitation initial velocity is important, such as a ship, it is not possible to set the pitch value of the propeller blade section so that the angle of attack of the root section of the propeller blade is positive (+).

Generally, the propeller inlet flow determined by the propeller shaft member or the propeller shaft inclination is used to provide an appropriate angle of attack distribution, that is, the cross section of the root portion of the propeller blades at which the cavitation initial velocity of both the pressure and suction surfaces reaches a certain level. Set the pitch angle. In other words, in the situation where the characteristics of the inflow (nominal return) flowing into the propeller determined by the propeller shaft member or the propeller shaft inclination do not change, there is a limit to improving the cavitation initial velocity of the root portion of the propeller blade by changing only the propeller shape. Means that.

In order to overcome this limitation, the present invention is directed to improving the cavitation parasitic speed of the root portion of the propeller blades 120, that is, the propeller blades 120 of the propeller blades 120. This is to change the direction of angle of attack based on the angle of attack of the root section.

As shown in FIG. 4, in the structure according to Example (0) including the flow control member 130, unlike the structure according to Comparative Example 00 without the flow control member 130, the y-axis value − Values below 4.00 have been changed to values above -4.00. Accordingly, in the structure according to Comparative Example (X), the deviation was T1, but in the structure according to Example (0), the deviation was reduced to T2.

That is, in the flow control apparatus according to the present invention, the flow control member 130 is formed on the circumferential surface of the propulsion shaft member 110, the propeller blade angle position area where the angle of attack of the cross section of the root portion of the propeller blade becomes a negative value By being formed in the front area to be treated, the absolute value of the negative (-) value can be reduced as a whole or converted into a positive (+) value. From this result, it can be seen that the pressure surface pressure of the cross section of the root portion of the propeller blade 120 is increased, thereby reducing the probability of cavitation in this portion.

In general, as the speed of the ship increases, the inflow amount (velocity) of the fluid flowing into the propeller increases as the rotation speed of the propeller increases, and thus the flow pressure decreases, thereby increasing the cavitation, but the open shaft according to the present invention. In the ship's flow control device, the flow control member 130 flows into the root portion of the propeller blade 120 in a region having a high probability of occurrence of pressure surface cavitation in a specific area, that is, the cross section of the root portion of the propeller blade 120. The inlet angle changes. Accordingly, the generation of cavitation at the pressure side of the root portion of the propeller blade 120 at the same speed is reduced, and finally the cavitation initial velocity of the root portion suction surface of the propeller blade 120 in the situation that the shape of the propeller root portion is finally determined. The cavitation initial velocity of the cross-sectional pressure surface of the root portion of the propeller blades 120 is increased without decreasing.

On the other hand, when one flow control member 130 is formed on the circumferential surface of the propulsion shaft member 110 in the flow control device according to the present invention, the flow control member 130 is a propeller blade on the circumferential surface of the propulsion shaft member 110. The angle of attack of the cross section of the root portion of 120 may be formed near the propeller blade angle position, which is the lowest value. Accordingly, the deviation of the angle of attack can be minimized only by forming one flow control member 130. Meanwhile, as described above, in the flow control apparatus according to the present invention, the base portion 131 of the flow control member 130 may be plural. The base parts 131 of the plurality of flow control members 130 may be arranged to be spaced apart from each other by a predetermined distance, and the length, thickness, and installation angle of the base parts 130 based on the axial direction of the main propulsion shaft are different from each other. Can be. For example, the base portion 131 of the flow control member 130 may be composed of two. However, the base portion 131 of the flow control member 130 is not limited to two.

On the other hand, a plurality of flow control member 130 may also be formed on the thrust surface of the propulsion shaft member 110, the present invention is not limited to one flow control member (130).

On the other hand, in the flow control apparatus according to the embodiment of the present invention, when the flow control member 130 is composed of a plurality of base portion 131, the plurality of base portion 131 is a propeller blade on the circumferential surface of the propulsion shaft member 110 The angle of attack of the root section cross section may be formed in a region that becomes a negative (-) value.

That is, in other words, the base portion 131 is formed on the circumferential surface of the propeller shaft member 110, the angle of attack of the root portion cross-section of the propeller blade relative to the propeller blade angle position on the rotation surface of the propeller blade is negative (- ) Area It may be formed in the front area to be raised.

In this case, the plurality of base parts 131 may be formed in the vicinity of the point where the angle of attack of the propeller blade root portion cross section becomes the minimum value based on the propeller blade angle position on the circumferential surface of the propeller shaft member 110.

In other words, the base portion 131 is formed on the circumferential surface of the propulsion shaft member 110, the angle of attack of the propeller blade root section cross-section based on the propeller blade angle position on the rotation surface of the propeller blade is the minimum value It may be formed near the front point corresponding to the.

For example, according to an embodiment of the present invention, when the base portion 131 of the flow control member 130 is two, on the circumferential surface of the propulsion shaft member 110, the propeller blade angle of the propeller blades relative to the position Two base parts 131 may be formed such that a point at which the angle of attack becomes a minimum is positioned between the two base parts 131. Referring to the drawings in more detail, as shown in Fig. 4, since the X-axis value at which the angle of attack of the cross section of the boundary portion with the propeller hub in the propeller blade is the minimum value is approximately 240 °, in Fig. 4 the flow control member Two base portions 131 constituting 130 are formed at positions where the propeller blade angle positions are 220 ° and 250 °, respectively, on the circumference of the propulsion shaft member 110.

For this reason, in the structure according to the embodiment (0) including the flow control member 130 as shown in FIG. 4, the angle of attack at 220 ° and 250 ^o is a position where two base portions 131 are installed. It can be seen that the angle of view was greatly increased compared to X), and the angle of attack at the periphery of the position where the base portion 131 was installed was also increased. In particular, in the comparative example (X), the angle of attack increased considerably due to the influence of the two base parts 131 around 240 °, which was the lowest value.

However, depending on the shape and size of the propeller blade 120, the structure of the propulsion shaft member 110 and the peripheral member, the measured angle of attack distribution can be changed. That is, the angle of attack can be changed according to the detailed structure of the vessel 10, and thus the installation position of the flow control member 130 can be changed, so that the base portion 131 of the flow control member 130 is the propulsion shaft member. The propeller blade angle position on the periphery of 110 is not necessarily limited to being positioned between 220, 250, or two angles.

5, the graph on the left shows that the flow control member is not formed. An inflow flow field or nominal return flow distribution on the propeller blade face in Comparative Example (X), and the graph on the right is a flow field or nominal return distribution in Example (0) in which the flow control member 130 is formed.

Each flow field is shown relative to the hull forward and rearward, and the direction of rotation of the propeller is clockwise. In addition, in FIG. 5, the color of each flow field represents the magnitude of the forward component velocity of the ship, and the arrows indicate the flow direction of the flow in the remaining directions except for the forward direction at each point. The region G in FIG. 5 represents the vicinity of the propeller root in the propeller radial direction and the vicinity of the X axis value in FIG. 4 in the propeller rotation direction from 200 ^o to 300 °. Referring to FIG. 5, in the flow control apparatus according to the present invention, as the flow control member 130 is formed in a specific region of the circumferential surface of the propeller shaft member whose angle of attack of the propeller blade is negative, G of the comparative example (X) It can be seen that the induced flow direction of the region and the G region of the example (0) is changed.

If the velocity vector in the G region of the comparative example (X) is mainly directed upward, the velocity vector in the G region of the example (0) is directed toward the propeller center axis, so that the rotational speed component is greatly reduced.

As described above, the decrease in the propeller rotational velocity component of the G region means an increase in the angle of attack of the propeller blade cross-section, that is, an absolute value of the angle of attack, which is negative (-), and thus, in the pressure plane of the propeller cross-section as described above. It can be seen that the pressure drop in the direction of the decrease.

Therefore, as described above, in the flow control apparatus according to the present invention, the angle of attack of the root portion of the propeller blade 120 is minimized through the control of the inflow flowing into the propeller blade 120 by the flow control member 130. The angle of attack of the section is increased so that the pressure on the pressure surface is increased relatively at the same speed so that the probability of occurrence of cavitation in this part is reduced. Finally, the propeller blades 120 are controlled by the flow control device 130 according to the present invention. The cavitation velocities of the pressure face can be increased without decreasing the cavitation velocities of the root section cross section suction surface.

For example, in the structure that does not include the conventional flow control device, the cavitation start speed of the propeller blade root portion suction surface is 15 knots, and the cavitation start speed of the pressure surface is If the speed was 10 knots, in the case of an open shaft vessel including a flow control device, the cavitation initial speed of the suction surface can be increased to 15 knots without changing the cavitation initial speed of the suction surface to 15 knots.

While various embodiments of the present invention have been described above, the spirit of the present invention is not limited to the embodiments set forth herein, and those skilled in the art who understand the spirit of the present invention may add components within the same scope. Other embodiments may be easily proposed by changing, deleting, adding, etc., but this will also fall within the spirit of the present invention. Industrial Applicability

In the flow control apparatus of the open shaft vessel according to an embodiment of the present invention, the flow angle in the rotational angle position portion is minimized by the propeller inflow characteristics and the angle of attack determined by the cross-sectional reference pitch angle setting of the boundary between the propeller blades and the propeller hub The control unit is installed. As a result, the minus peak value in the angle of attack rises relatively, so that the minimum pressure value is increased when one pressure reference pressure change of the pressure surface of the propeller blade section is increased, compared to the case without the flow control device. The probability of occurrence of cavitation can be reduced. Thereby, the cavitation initial velocity of the cross-sectional reference pressure surface of the boundary between the propeller blades and the propeller hub can be improved without reducing the same part suction surface cavitation initial velocity.

Claims

[Range of request]

[Claim 1]

Propulsion shaft member exposed to the outside toward the rear of the ship,

Propeller hub rotatably coupled to the propulsion shaft member,

Propeller blades located on the outer surface of the propeller hub, and

It includes a flow control member disposed in front of the propeller blades relative to the direction in which the ship is advanced,

The flow control member,

A plurality of base parts protruding from the periphery of the propulsion shaft member and spaced apart from each other;

And a connection part connecting the plurality of base parts.

_

[Claim 2]

The method of claim 1,

The plurality of base portions and the connecting portion integrally formed, the flow control device of the open shaft vessel.

[Claim 3]

The method of claim 2,

The connecting portion is formed to be bent to protrude in a direction away from the propulsion shaft member, the flow control device of the open shaft vessel.

[Claim 4]

The method of claim 1,

Cross section of the base portion is made of hydrofoil sect ion, flow control device of an open shaft vessel.

[Claim 5]

The method of claim 1 The flow control member is formed in a region where the angle of attack (AOA) of the propeller blades on the circumferential surface of the propeller shaft member, the flow control device of an open shaft vessel.

[Claim 6]

The method of claim 1,

The flow control member is formed in the vicinity of the point of the angle of attack (AOA) of the propeller blades on the circumferential surface of the propulsion shaft member, the flow control device of the open shaft vessel.

[Claim 7]

The method of claim 6,

The base portion is two,

And the two base portions are formed between the two base portions at a point at which an angle of attack (AOA) of the propeller blade becomes the minimum value on the circumferential surface of the propulsion shaft member.

[Claim 8]

The method according to any one of claims 1 to 7,

And the angle of attack is the angle of attack at the cross section of the boundary portion with the propeller hub at the propeller blades.

[Claim 9]

In claim 11,

Each of the plurality of base portions are spaced apart from each other at regular intervals, the flow control device of the open shaft vessel.

[Claim 10]

According to claim 11,

Said connecting portion connecting an end of each of said base portions, an open shaft Vessel Flow Control System.