TW201731727A - Lift generator - Google Patents

Abstract

The present invention provides a lift generator (10) located in front of the screw propeller (3) of the ship (1). The lift generator (10) has a wall (7) elongating in the circumferential direction around the extension line (Ce) of the center axis (C) of the screw propeller (3). A passage penetrating in the direction of the extension line (Ce) is formed in the inner side of the wall (7). In the wing section, an outer side surface forming the outer peripheral surface (7a) of the wall (7) is twisted toward, the inner side to form an indent. In the wing section, the wing section satisfies |dt/dx| ≤ 0.15 over the entire range from a default location which becomes the maximum thickness to rear edge. The dx is a tiny change amount of the position coordinate X in the chord direction of the wing section, the dt is a tiny change amount of the thickness relative to the dx, |dt/dx| is the volume of the dt/dx.

Description

Lift generator

The present invention relates to a lift generator in a ship that is located in front of a propeller.

Conventionally, there has been a case where a duct as a lift generating body is provided in front of a propeller propeller at the stern of the ship. By the rotation of the propeller, the flow of water from the front side to the rear side of the ship is generated in the lift generating body. The profile of the lift generating body is wing-shaped, and therefore, the lift is generated by the water flow in the lift generating body. This lift has a component (forward component) in the direction toward the front of the ship. As a result, the power for rotating the propeller is reduced. Such a lift generating system is described, for example, as a conduit in Patent Documents 1 and 2.

(previous technical literature) (Patent Literature)

Patent Document 1: Japanese Laid-Open Patent Publication No. 2011-42204

Patent Document 2: Japanese Patent No. 4097742

It is expected that there will be a lift generating body which can further reduce the power for rotating the propeller propeller.

That is, it is an object of the present invention to provide a lift generating body which can more strongly advance a ship when the propeller is rotated with the same power as compared with a conventional lift generating body (catheter).

In order to achieve the above object, according to the present invention, a lift generating body is provided in a ship having a propelling propeller, which is located before the propulsion propeller, and the lift generating system has a center toward the center of the propulsion propeller a wall portion extending in the circumferential direction of the extension line of the shaft, wherein the wall portion forms a flow path penetrating in the direction of the extension line, and is formed by a virtual plane including the extension line in a predetermined range in the circumferential direction The shape of the cross section of the wall portion is a wing shape, and in the wing shape, the outer side surface forming the outer peripheral surface of the wall portion is curved toward the inner side so as to form a recess, and the thickness of the airfoil becomes the thickness The maximum set position moves backward and gradually becomes smaller, and the entire range from the set position to the trailing edge of the wing shape satisfies |dt/dx|≦0.15, in which dx is the aforementioned wing The small change amount of the position coordinate x in the chord direction of the shape, dt is the small change amount of the thickness t with respect to dx, and |dt/dx| is the magnitude of dt/dx.

In the present invention, in the above-described wing shape, the outer side surface forming the outer peripheral surface of the wall portion is curved toward the inner side so as to form a recess. borrow Thus, in the airfoil, the circulation of the flow becomes large, and as a result, the pressure on the inner side is lowered and the lift is increased. Due to the increase in the lift of the wing shape, the forward component of the lift of the wing shape also becomes larger (hereinafter, this action is referred to as an increase in the force toward the front component).

Furthermore, in the present invention, the ratio of the small change amount dx of the position x in the chord direction to the small change amount dt of the thickness t of the position x throughout the range from the set position to the trailing edge is the magnitude of the dt/dx ratio of the small change amount dt of the thickness t of the position x. It is 0.15 or less (the units of dx and dt are the same). Thereby, even if the above-described depression is formed, the fluid resistance of the airfoil can be suppressed to be small (hereinafter, this action is referred to as a reduction in fluid resistance).

According to the present invention, the effect of increasing the forward component of the lift force described above acts in conjunction with the above-described effect of reducing the fluid resistance, and the ship can be further advanced by the same power as compared with the conventional lift generator (see, for example, the following description). Comparative Examples 1, 2).

The above-described lift generating body can also be constructed as follows.

In the above-described airfoil shape, the outer side surface and the inner side surface forming the inner circumferential surface of the wall portion are integrally curved toward the side of the flow path.

Thus, each of the outer side surface and the inner side surface of the airfoil is integrally curved toward the inner side. Thereby, since the fluid is easily peeled off from the airfoil (especially the inner side), the fluid generated by the lift force is disturbed and the flow velocity thereof is lowered. Therefore, the flow of the reduced flow rate will flow into the propeller. As a result, the efficiency of the propeller is increased (hereinafter, this effect is referred to as an increase in propeller efficiency).

Therefore, the above-mentioned lift force acts on the front component, The effect of reducing the fluid resistance described above works in conjunction with the above-described propeller efficiency improvement, and the ship can be further advanced significantly using the same power as compared with the conventional lift generating body.

The wall portion has a lower end portion in which the outer peripheral surface faces vertically downward, and the length of the lower end portion is smaller than the length of the upper end portion of the wall portion in the direction of the extension line.

In the wall portion, resistance is likely to occur at the lower end portion of the outer peripheral surface facing the vertical lower portion.

On the other hand, in the above configuration, since the length of the lower end portion is made smaller than the length of the upper end portion in the wall portion, the resistance at the lower end portion can be suppressed.

The shape of the aforementioned cross section of the lower end portion is a wing shape but does not have the aforementioned recess or is not a wing shape.

As described above, the above-described recess or wing profile is not required at the end portion where the resistance is generated. Therefore, the cross-sectional shape of the lower end portion can be made simple.

The setting range is at least a part of a range of the circumferential direction in which the outer peripheral surface of the wall portion faces obliquely upward.

Within this range, a large lift force is generated in the wing shape.

According to the present invention, since the outer side of the airfoil is curved toward the inner side in such a manner as to form a recess, the lift generated in the airfoil becomes large. As a result, the forward component of the lift of the wing shape also becomes larger.

In addition, throughout the range from the set position to the trailing edge, the chord The magnitude of the ratio dt/dx of the small amount of change dx to the position x and the small amount of change dt of the thickness x of the position x is 0.15 or less. Thereby, even if the above-mentioned depression is formed, the fluid resistance of the airfoil can be suppressed to be small.

The increase in the forward component of the lift acts in conjunction with the reduction of the fluid resistance of the airfoil, and the ship can be propelled more significantly with the same power as compared to the conventional lift generator.

1‧‧‧ ship

1a‧‧‧Stern

3‧‧‧propelled propeller

5‧‧‧Flow path

6‧‧‧Combined components

7‧‧‧ wall

7a‧‧‧ outer perimeter

7b‧‧‧ inner circumference

9‧‧‧wing

9a‧‧‧Outside

9b‧‧‧ inside

10‧‧‧ Lifting body

11‧‧‧ dent

13‧‧‧ Backend

Bc‧‧‧ chord

C‧‧‧ center axis

Extension line of Ce‧‧‧ central axis

Distance between the extension of the D1‧‧‧ center axis and the point on the chord

Lc‧‧‧ arc

Ps‧‧‧Set location

Pf‧‧‧ leading edge

Pr‧‧‧ trailing edge

R‧‧‧Through the area

T‧‧‧thickness

θ 1, θ 2, θ 3‧‧‧ range

Fig. 1A is a view showing a stern portion of a ship to which a lift generating body according to an embodiment of the present invention is applied.

Figure 1B is a B-B arrow view of Figure 1A.

Fig. 2A is a cross-sectional view taken along line II-II of Fig. 1B.

Figure 2B is a cross-sectional view taken along line II-II of Figure 1B and showing other features of the airfoil.

Fig. 3A is a view for explaining a comparison between a wing shape of a specific example of the embodiment of the present invention and a wing shape of Comparative Example 1.

Fig. 3B is a view showing another example of comparison between the specific example and the comparative example 1.

Fig. 3C is a view showing another example of comparison between the specific example and the comparative example 1.

Fig. 4A is a view for explaining a comparison between a wing shape of a specific example of the embodiment of the present invention and a wing shape of Comparative Example 2.

Fig. 4B is a view showing another example of comparison between the specific example and the comparative example 2.

Fig. 5A shows the difference between the shape of the airfoil of the specific example and the shape of the airfoil of Comparative Example 2.

Fig. 5B is a view showing the difference between the shape of the specific example and the comparative example 2 chart.

Fig. 6 shows a modified example of the lift generating body.

Preferred embodiments of the present invention will be described with reference to the drawings. In the drawings, the same reference numerals are given to the same portions in the respective drawings, and the description thereof will be omitted.

Fig. 1A is a side view showing the stern portion 1a of the ship 1 to which the lift generating body 10 according to the embodiment of the present invention is applied.

The ship 1 is a person sailing in the sea, lake or river. The ship 1 is for example a ship or a ship. The ship 1 is provided with a propulsion propeller 3 at the stern portion 1a. The propulsion propeller 3 can also be a screw propeller. The propeller 3 is driven to rotate in the water to generate the forward thrust of the ship 1. By the rotation of the propeller propeller 3, the flow toward the propulsion propeller 3 occurs in the direction from the front side to the rear side of the ship 1 (hereinafter referred to as the rearward direction). Further, in the present case, the front side refers to the front side (the bow side) of the ship 1, and the rear side refers to the rear side (the stern side) of the ship 1.

The lift generating body 10 is disposed in front of the propulsion propeller 3. In other words, the lift generating body 10 (the wing shape 9 to be described later) is disposed in the above-described flow in the backward direction of the propulsion propeller 3. In Fig. 1A, the lift generating body 10 is positioned directly in front of the propulsion propeller 3.

Figure 1B is a B-B arrow view of Figure 1A. The lift generating body 10 has a wall portion 7 that extends in a circumferential direction (hereinafter simply referred to as a circumferential direction) around an extension line Ce of the central axis C of the propeller propeller 3. The wall portion 7 has a flow path 5 that penetrates in the direction of the extension line Ce on the inner side. Extension cord The Ce is located in the flow path 5. Further, in the first drawing, the circumferential end surface of the upper end portion of the wall portion 7 of the lift generating body 10 is coupled to the stern portion 1a, and the lift generating body 10 is also coupled to the stern portion 1a via the coupling member 6. However, the lift generating body 10 can also be coupled to the stern portion 1a by other means. The central axis C may also face the direction of the center line of the hull of the ship 1 (the left-right direction of FIG. 1A), or may be inclined from the direction of the center line toward the left and right sides of the ship 1 and the upper and lower sides.

Fig. 2A is a cross-sectional view taken along line II-II of Fig. 1B. In the setting range in the circumferential direction (hereinafter simply referred to as the setting range), the shape of the cross section of the wall portion 7 formed by the virtual plane including the extension line Ce is the wing shape 9. The wing shape 9 will be described based on Fig. 2. The shape of the cross section of any of the circumferential direction positions within the set range may be the same as that of the wing shape 9 described below.

The setting range includes at least a range θ 1 in which the outer peripheral surface 7a of the wall portion 7 faces obliquely upward (see FIG. 1B). In the present embodiment, the setting range is the range in which all the wall portions 7 extend in the circumferential direction. In this case, in the first drawing, the setting range includes the range θ 1 ; the circumferential surface 7 a of the outer peripheral surface 7 a of the wall portion 7 is oriented horizontally or obliquely downward (see FIG. 1B ); and the outer periphery of the wall portion 7 The surface 7a faces a range θ 3 in the circumferential direction of the vertical lower side.

The chord Bc of the airfoil 9 (i.e., the line connecting the leading edge Pf and the trailing edge Pr of the airfoil 9 in Fig. 2A) is inclined from the central axis C of the propulsion propeller 3. Further, the point on the chord Bc is gradually separated from the extension line Ce of the central axis C as it moves toward the front side. That is, as the point on the chord Bc moves toward the front side, the direction orthogonal to the extension line Ce (radial direction) The distance D1 between the point on the chord Bc and the extension line Ce becomes large. Thereby, the lift with the forward component is generated in the wing shape 9. For convenience, in FIG. 2A, the extension line Ce is moved in parallel from the actual position toward the vicinity of the airfoil 9 to illustrate the presentation.

In the airfoil 9 (that is, the contour of the airfoil 9), the outer peripheral surface 7a of the wall portion 7 (see FIGS. 1A and 1B) is formed to face the inner side (flow path) in such a manner as to form the recess 11 5 side) curved. In the present embodiment, in the airfoil 9, the outer side surface 9a and the inner side surface 9b of the inner peripheral surface 7b forming the wall portion 7 are integrally curved inward. In response to this, the lift generating body 10 is close to the propelling propeller 3 so that the turbulent flow caused by the fluid separation of the outer side surface 9a and the inner side surface 9b (particularly the inner side surface 9b) flows into the propelling propeller 3.

The thickness t of the airfoil 9 is maximized at the set position Ps in the chord direction. The chord direction refers to the direction parallel to the chord Bc. In the present embodiment, the set position Ps is located closer to the front side than the center of the chord Bc (that is, the point at which the chord Bc is equally divided). However, the set position Ps may be the center of the chord Bc or may be located closer to the rear side than the center of the chord Bc.

The thickness t of the airfoil 9 is the thickness in the direction orthogonal to the camber line Lc of the airfoil 9. The arc Lc is a line extending from the leading edge Pf to the trailing edge Pr, and is a line located at an equal distance from the outer side surface 9a and the inner side surface 9b of the airfoil 9 (i.e., a point chain line in Fig. 2A). Further, the thickness t of the wing shape 9 on the position coordinate x of the chord direction means that the point on the arc Lc which becomes the coordinate x in the chord direction is orthogonal to the arc Lc and The outer side surface 9a extends to the length of the line segment of the inner side surface 9b. The thickness t of the airfoil 9 gradually increases as it moves toward the rear side from the leading edge Pf to the set position Ps, and gradually decreases as it moves toward the rear side from the set position Ps to the trailing edge Pr.

As is apparent from Fig. 1A, the chord length of the airfoil 9 of the cross section of the wall portion 7 (or the size of the airfoil 9 in the direction of the extension line Ce) decreases as moving downward. Therefore, the chord length of the lower end portion of the wall portion 7 (i.e., the portion of the range θ 3 ) is smaller than the chord length of the upper end portion of the wall portion 7.

The lift generating body 10 of the present embodiment has the following features A to C.

(Feature A)

In Fig. 2A, the airfoil 9 satisfies the following inequality throughout the entire range from the set position Ps to the trailing edge Pr: |dt/dx|≦0.15

Where dx is the small change amount of the position coordinate x of the chord direction of the airfoil 9, dt is the small change amount of the thickness t with respect to the dx of the position coordinate x, and |dt/dx| is the magnitude of the dt/dx (absolute value) ). Dt/dx may also be a differential depending on the thickness t of the position coordinate x. In other words, the ratio of dt/dx is dt to the small amount of change dx. The position coordinate x is the same as the unit of the thickness t. In the entire range from the set position Ps to the trailing edge Pr, since |dt/dx| is 0.15 or less, the fluid resistance of the airfoil 9 can be suppressed to be low.

(Feature B)

Figure 2B is a cross-sectional view taken along line II-II of Figure 1B and showing other features of the airfoil 9. The length of the chord Bc is C, the maximum value of the thickness t of the airfoil 9 is tm, and the maximum distance between the chord Bc and the outer side surface 9a in the direction orthogonal to the chord direction is Dm.

Preferably, tm/C satisfies 0.05 ≦tm/C ≦ 0.3.

Dm/tm preferably satisfies 0.06 < Dm / tm ≦ 0.4, 0.2 < Dm / tm ≦ 0.4, or 0.3 < Dm / tm ≦ 0.4.

The Dm/tm system is an index indicating the size of the recess 11. By setting the magnitude of Dm/tm as described above, the circulation of the flow in the airfoil 9 becomes larger as compared with the case where the recess 11 is not provided. As a result, the pressure of the inner side surface 9b is lowered and the lift generated in the airfoil 9 is increased. Therefore, the forward component of the lift of the airfoil 9 also becomes large.

(Feature C)

In Fig. 1A, the entirety of the rear end 13 of the wall portion 7 (i.e., the end 13 extending in the circumferential direction) is in the direction from the center line of the hull of the ship 1 (the left and right direction of the figure). The region R (hereinafter referred to as the passage region R of the propulsion propeller 3) passing through the propeller propeller 3 is rotated. In this configuration, since the airfoil 9 is turbulent as described above, all or substantially all of the flow rate reduction flow flows into the passage region R of the propulsion propeller 3. As a result, the efficiency of the propeller 3 will be more surely improved.

However, according to the present embodiment, from the hull of the ship 1 When viewed in the direction of the heart line, the lower end of the wall portion 7 is only required to be located in the passage region R of the propulsion propeller 3. In this case, it is preferable that the extension line Ce of the center axis C of the propulsion propeller 3 is located at the flow path 5 (that is, inside the wall portion 7).

Next, a specific example of the wing shape 9 of the present embodiment will be described in comparison with Comparative Example 1.

Fig. 3A shows the airfoil shape of the airfoil 9 and the comparative example 1 of the specific example of the embodiment. In Fig. 3A, a solid line shows a specific example, and a broken line shows Comparative Example 1. The airfoil 9 of Comparative Example 1 has substantially no depression on the outer side.

As shown in Fig. 3B, in the specific example and the airfoil of Comparative Example 1, the lift in the same direction was generated, but the lift of the specific example was larger than that of Comparative Example 1. As a result, the specific example of the front component of the lift was larger than that of the comparative example 1.

In the third embodiment, the effect of reducing the power of the propeller propeller 3 (hereinafter referred to as the power reduction effect) is shown as the fluid resistance reduction amount of the ship 1 when a certain thrust is generated in the ship. In other words, the 3C is a numerical value obtained by converting the thrust obtained by the rotation of the propeller propeller 3, the fluid resistance of the lift generating body 10, and the lift power to the fluid resistance reduction amount of the ship 1. The results of Fig. 3C are obtained in a simulation performed by CFD (computational fluid dynamics). In this simulation, in the specific example and the comparative example 1, the wing shape was made different as shown in FIG. 3A, and the other conditions were made the same.

As shown in FIG. 3C, when the fluid resistance reduction amount of Comparative Example 1 is set to 100%, the fluid resistance reduction amount of the specific example is slightly higher than that. 110%. Therefore, in a specific example, the fluid resistance (power) is reduced by as much as 10% compared with Comparative Example 1.

Next, a specific example of the wing shape 9 of the present embodiment will be described in comparison with Comparative Example 2.

Fig. 4A is a view showing a wing shape of a wing shape 9 and a comparative example 2 of a specific example of the embodiment. In Fig. 4A, the solid line shows a specific example and is the same as the case of Fig. 3A, and the broken line shows Comparative Example 2. The airfoil of Comparative Example 2 has a recess of the same size as the specific example, but the differential dt/dx of the thickness t depending on the position coordinate x of the chord direction is different from the specific example.

Figure 5A is a graph showing the relationship between the position coordinate x of the chord direction and the thickness t of the airfoil 9. In Fig. 5A, the horizontal axis shows the coordinate x when the coordinate x of the leading edge Pf is set to 0 and the chord length is set to 1. In Fig. 5A, the vertical axis shows the value (thickness/chord length) obtained by dividing the thickness of the airfoil 9 by the chord length.

Fig. 5B is a graph showing the relationship between the position coordinate x of the chord direction and the above differential dt/dx. In Fig. 5B, the horizontal axis shows the coordinate x when the coordinate x of the leading edge Pf is set to 0 and the chord length is set to 1. In Fig. 5B, the vertical axis shows the value of the differential dt/dx.

In the specific example and the comparative example 2, the thickness t of the airfoil 9 is as shown in Fig. 5A, and the set position Ps at which the coordinate x is 0.3 is the largest.

In a specific example, the size of dt/dx is as shown in Fig. 5B, and the full range from the set position Ps to the trailing edge Pr of the airfoil 9 (i.e., the position of the rear end 13) is smaller than 0.15. In Comparative Example 2, it did not become such a situation. shape. That is, in Comparative Example 2, the size of dt/dx was 0.15 or more over the range from the position where the coordinate x is 0.86 to the rear end of the airfoil.

Fig. 4B is a value obtained by converting the power reduction effect into the ship's fluid resistance reduction amount in the same manner as in the case of Fig. 3C. The results of Figure 4B are derived from the simulations performed by CFD. In the simulation, in the specific example and the comparative example 2, the wing shapes were set to be different as shown in FIGS. 4A, 5A, and 5B, and other conditions were set to be the same.

As shown in FIG. 4B, when the fluid resistance reduction amount of Comparative Example 2 is 100%, the fluid resistance reduction amount of the specific example is slightly less than 115%. Therefore, in a specific example, the fluid resistance (power) is reduced by as much as approximately 15% compared to the comparative example.

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the technical idea of the present invention. For example, any of the following Modifications 1 to 3 can be used singly, and two or more of Modifications 1 to 3 can be arbitrarily selected. At this time, the points which are not described below may be the same as described above.

(Modification 1)

The shape of the cross section of the wall portion 7 is the above-described setting range of the above-described wing shape 9, and is not limited to the above. For example, the setting range may not include one or both of the above-described range θ 2 and range θ 3 shown in FIG. 1B. Furthermore, the above setting range may include only one of the above-mentioned ranges θ 1 . In this case, the set range may not include one or both of the range θ 2 and the range θ 3 described above.

(Modification 2)

Fig. 6 is a view corresponding to Fig. 1B, showing a modified example 2 of the lift generating body 10. As shown in Fig. 6, the flow path 5 on the inner side of the wall portion 7 can also be opened vertically (radially). Further, the flow path 5 may be opened in the other radial direction (that is, the direction orthogonal to the extension line Ce).

(Change 3)

When a plurality of propelling propellers 3 are provided in the stern portion 1a, the lift generating body 10 may be provided in front of each of the propelling propellers 3.

(Modification 4)

The above-described cross section of the lower end portion of the wall portion 7 may have a wing shape but does not have the above-described recess 11. Or the shape of the cross section of the lower end portion may not be a wing shape.

1‧‧‧ ship

1a‧‧‧Stern

3‧‧‧propelled propeller

5‧‧‧Flow path

6‧‧‧Combined components

7‧‧‧ wall

7a‧‧‧ outer perimeter

7b‧‧‧ inner circumference

10‧‧‧ Lifting body

13‧‧‧ Backend

C‧‧‧ center axis

Extension line of Ce‧‧‧ central axis

θ 1, θ 2, θ 3‧‧‧ range

Claims (5)

A lift generating body is provided in a ship having a propeller propeller, which is located before the propulsion propeller, and the lift generating system has a wall portion extending in a circumferential direction around an extension line of a central axis of the propelling propeller. The wall portion has a flow path penetrating in the direction of the extension line, and a shape of a cross section of the wall portion formed by the imaginary plane including the extension line is a wing shape in a predetermined range in the circumferential direction. In the above-described airfoil shape, the outer side surface forming the outer peripheral surface of the wall portion is curved toward the inner side so as to form a recess, and the thickness of the airfoil gradually decreases as it moves rearward from the set position at which the thickness becomes the maximum. The entire range from the set position to the trailing edge of the airfoil, the wing shape satisfies |dt / dx | ≦ 0.15, in which dx is a small change in the position coordinate x of the chord direction of the wing shape The amount dt is a small amount of change of the thickness t with respect to dx, and |dt/dx| is the magnitude of dt/dx. The lift generating body according to the first aspect of the invention, wherein the outer side surface and the inner side surface forming the inner peripheral surface of the wall portion are integrally curved toward the side of the flow path. The lift generating body according to claim 1 or 2, wherein the wall portion has a lower end portion whose outer peripheral surface faces vertically downward, and the length of the lower end portion is longer than the aforementioned direction in the direction of the extension line The length of the upper end portion of the wall portion is smaller. The lift generating body according to claim 3, wherein the shape of the cross section of the lower end portion is a wing shape but does not have the aforementioned recess or is not a wing shape. The lift generating body according to any one of the first to fourth aspect, wherein the set range is at least a part of a range of the circumferential direction in which the outer peripheral surface of the wall portion faces obliquely upward.