WO2018105451A1 - Fin unit device and ship provided with same - Google Patents

Abstract

The present invention comprises: a duct (22) which is located in front of a propeller of a ship, and is fixed to a bossing (11) side so as to surround the rotational axis (L1) of the propeller; inside fins (24) which have outer ends fixed to the inner peripheral side of the duct (22) and extend radially inward towards the rotational axis (L1); and outside fins (25) which are located in the extension direction of the inside fins (24), and which have inner ends fixed to the outer peripheral side of the duct (22) and extend radially outward. If the rotation of the propeller is clockwise as viewed from the rear of the ship, the attack angle with respect to influent water is formed on the port side, and θi > θo is set where θi is the installation angle of the inside fins (24) with respect to a reference plane including the rotational axis (L1) and θo is the installation angle of the outside fins (25) with respect to the reference plane.

Description

Fin unit device and ship equipped with the same

The present invention relates to a fin unit device for improving a flow field upstream of a propeller and a ship equipped with the same.

In order to improve the propulsion performance of a ship, it is known to provide a fin unit that induces a swirling flow in the direction opposite to the propeller on the upstream side of the propeller (see Patent Documents 1 and 2).
Patent Document 3 discloses a configuration in which a cylindrical front nozzle fixed to a bossing is provided so that external fins protrude outward. Furthermore, it is described that the preliminary swirl can be optimized by having different angles of attack between the outer fin and the inner fin.

Japanese Patent No. 5281559 Japanese Patent No. 5901512 Japanese Patent No. 5357319 (paragraph [0033])

However, Patent Document 3 discloses that the angle of attack between the external fin and the internal fin is different. However, the flow field on the upstream side of the propeller is complicated and the flow direction is different at each position. The angle of attack determined by the installation angle is not fixed uniformly. That is, if fins are installed at different positions, the angle of attack of each fin will be different even if the fin installation angle is the same. Therefore, the matter of disposing fins at different angles of attack disclosed in Patent Document 3 does not make technical sense and does not indicate specific problem solving means.

This invention is made in view of such a situation, Comprising: The fin unit apparatus which can improve the propulsion performance of a ship by improving the flow field of a propeller upstream, and a ship provided with the same are provided. For the purpose.

In order to solve the above problems, the fin unit device of the present invention and a ship equipped with the same employ the following means.

A fin unit device according to an aspect of the present invention includes a duct that is located in front of a propeller vessel and is fixed to a boshing side so as to surround a rotation axis of the propeller, and an outer end portion on an inner peripheral side of the duct. An inner fin that is fixed and extends radially inward toward the rotational axis, and is positioned in the extending direction of the inner fin, and an inner end is fixed to the outer peripheral side of the duct, and is radially outward. And at least a pair of the inner fin and the outer fin are on the port side when the propeller is rotated clockwise as viewed from the rear of the ship, or is rotated counterclockwise when the propeller is viewed from the rear of the ship. In this case, on the starboard side, an angle of attack is formed with respect to the inflowing water, the installation angle of the inner fin with respect to the reference plane including the rotation axis is θi, and the installation angle of the outer fin with respect to the reference plane To the case of a θo, there is a θi> θo.

The inner fin and the outer fin fixed to the duct located in front of the propeller ship promote the pre-turning upstream of the propeller to improve the propeller efficiency.
Since the inner fin and the outer fin are fixed to the duct, the inner fin and the outer fin can be easily installed via the duct even if the inner fin and the outer fin have different installation angles.
The upstream side of the propeller becomes a complicated flow field due to the hull shape such as bossing. For example, in a plane orthogonal to the propeller rotation axis, the flow from the upper side to the lower side is mainly on the inner peripheral side centered on the propeller rotation axis, and the flow from the lower side to the upper side is mainly along the circumferential direction on the outer peripheral side. It becomes. The inventors have found that the installation angle between the inner fin and the outer fin can be optimized by paying attention to this flow field.
Specifically, an angle of attack is formed with respect to the inflowing water on the starboard side in the case of propeller right rotation (starboard side in the case of propeller left rotation), and the inner fin relative to the reference plane including the rotation axis is formed. When the installation angle is θi and the installation angle of the outer fin with respect to the reference plane is θo, the relationship θi> θo is established. The reason is as follows.
On the port side in the case of propeller right rotation (on the starboard side in the case of left rotation of the propeller), the flow field on the inner peripheral side is mainly the flow from the upper side to the lower side, and the direction facing the propeller rotating from the lower side to the upper side. Become. For this reason, it is preferable to increase the installation angle θi of the inner fin so as to promote the flow from the upper side to the lower side.
On the other hand, the flow field on the outer peripheral side is mainly from the bottom to the top, and is in the same direction as the propeller rotating from the bottom to the top. For this reason, it is preferable that the outer fin has an installation angle that changes the flow downward. However, since the flow velocity in the propeller rotation axis direction is larger on the outer peripheral side than on the inner peripheral side, setting the installation angle of the outer fin to obtain a large angle of attack is not preferable because the outer fin becomes resistance to flow. Therefore, the installation angle θo of the outer fin is set smaller than the installation angle θi of the inner fin (θi> θo).
As described above, the flow field on the upstream side of the propeller is improved on the inner peripheral side and the outer peripheral side, and the propulsion performance of the ship can be improved.
In addition, when making an inner fin and an outer fin into a wing | blade shape, it is preferable to install facing the lower side | surface of a wing | blade shape. Thereby, the flow direction can be effectively changed from the upper side to the lower side using the ventral shape.

The fin unit device according to an aspect of the present invention includes a duct that is positioned in front of the propeller and is fixed to the boshing side so as to surround the rotation axis of the propeller, and an outer end on the inner peripheral side of the duct. The inner fin is fixed in the radial direction toward the rotation axis, the inner fin is positioned in the extending direction of the inner fin, and the inner end is fixed on the outer peripheral side of the duct. And at least a pair of the inner fin and the outer fin when the propeller rotates clockwise when viewed from the rear of the ship, or when the propeller is viewed from the rear of the ship. In the case of left rotation, on the port side, an angle of attack is formed with respect to the inflowing water, the installation angle of the inner fin with respect to the reference plane including the rotation axis is θi, and the outer fin with respect to the reference plane is The 置角 degree when the .theta.o, there is a .theta.i <.theta.o.

The inner fin and the outer fin fixed to the duct located in front of the propeller ship promote the pre-turning upstream of the propeller to improve the propeller efficiency.
Since the inner fin and the outer fin are fixed to the duct, the inner fin and the outer fin can be easily installed via the duct even if the inner fin and the outer fin have different installation angles.
The upstream side of the propeller becomes a complicated flow field due to the hull shape such as bossing. For example, in a plane orthogonal to the propeller rotation axis, the flow from the upper side to the lower side is mainly on the inner peripheral side centered on the propeller rotation axis, and the flow from the lower side to the upper side is mainly along the circumferential direction on the outer peripheral side. It becomes. The inventors have found that the installation angle between the inner fin and the outer fin can be optimized by paying attention to this flow field.
Specifically, in the case of propeller right rotation, the angle of attack is formed on the starboard side (portal side in the case of propeller left rotation) with respect to the inflowing water, and the inner fin relative to the reference plane including the rotation axis is formed. When the installation angle is θi and the installation angle of the outer fin with respect to the reference plane is θo, the relationship θi <θo is established.
On the starboard side in the case of propeller right rotation (on the starboard side in the case of left rotation of the propeller), the flow field on the inner peripheral side mainly flows from the upper side to the lower side, and is in the same direction as the propeller rotating from the upper side to the lower side. For this reason, it is preferable to increase the installation angle θi so that the inner fin changes its flow upward.
On the other hand, the flow field on the outer peripheral side is mainly from the bottom to the top, and is in a direction facing the propeller rotating from the bottom to the top. For this reason, it is preferable to increase the installation angle θo of the outer fin so as to promote the flow from the lower side to the upper side. Therefore, the installation angle θo of the outer fin is set larger than the installation angle θi of the inner fin (θi <θo).
As described above, the flow field upstream of the propeller is improved on the inner peripheral side and the outer peripheral side, and the propulsion performance can be improved.
In addition, when making an inner fin and an outer fin into a wing | blade shape, it is preferable to install facing the upper side of a wing | blade shape. Thereby, the flow direction can be effectively changed from below to above using the ventral shape.

The fin unit device according to an aspect of the present invention includes a duct that is positioned in front of the propeller and is fixed to the boshing side so as to surround the rotation axis of the propeller, and an outer end on the inner peripheral side of the duct. The inner fin extending radially inward toward the rotation axis and the inner end fixed to the outer peripheral side of the duct at a position different from the extending direction of the inner fin. And an outer fin extending outward in the direction.

The inner fin and the outer fin fixed to the duct located in front of the propeller ship promote the pre-turning upstream of the propeller to improve the propeller efficiency.
Since the inner fin and the outer fin are fixed to the duct, the inner fin and the outer fin can be easily installed via the duct even if the inner fin and the outer fin have different installation angles.
The upstream side of the propeller becomes a complicated flow field due to the hull shape such as bossing. For example, in a plane orthogonal to the propeller rotation axis, the flow from the upper side to the lower side is mainly on the inner peripheral side centered on the propeller rotation axis, and the flow from the lower side to the upper side is mainly along the circumferential direction on the outer peripheral side. It becomes. The inventors have found that the installation angle between the inner fin and the outer fin can be optimized by paying attention to this flow field.
Specifically, the outer fin is provided at a position different from the extending direction of the inner fin. Inner fins and outer fins can be installed at appropriate positions independently on the inner and outer circumferential sides, which have different flow fields, and the flow field upstream of the propeller is improved on the inner and outer circumferential sides. Can be improved.
In addition, it is good also as combining with the above-mentioned invention regarding the installation angle of an inner side fin and an outer side fin.

Furthermore, in the fin unit device according to one aspect of the present invention, the outer fin is not provided below the duct.

The outer peripheral side below the duct is a region where the flow velocity in the direction of the propeller rotation axis is large, and the outer fin may become a resistance. Therefore, the outer fin is not provided below the duct. In such a case, the number of outer fins may be smaller than the number of inner fins.
The lower part of the duct means, for example, a region below a horizontal line passing through the propeller rotation axis when the duct is viewed from the rear of the ship.

Furthermore, in the fin unit device according to an aspect of the present invention, the propeller is on the starboard side when the propeller is rotated rightward when viewed from the rear of the ship, or the starboard side when the propeller is rotated left when viewed from the rear of the ship. The inner end of the outer fin is fixed to the duct at a position above the corresponding inner fin.

When the propeller is rotating clockwise when viewed from the rear of the ship, or on the starboard side when the propeller is rotating left when viewed from the rear of the ship, the inner end of the outer fin is connected to the corresponding inner fin. Was fixed to the duct at an upper position. This is because, on the port side in the case of propeller right rotation (on the starboard side in the case of propeller left rotation), a larger flow velocity in the direction of the propeller rotation axis can be avoided in the upper region. This is because the effect of field improvement is great.

The fin unit device according to an aspect of the present invention includes a duct that is positioned in front of the propeller and is fixed to the boshing side so as to surround the rotation axis of the propeller, and an outer end on the inner peripheral side of the duct. The inner fin is fixed in the radial direction toward the rotation axis, the inner fin is positioned in the extending direction of the inner fin, and the inner end is fixed on the outer peripheral side of the duct. An outer fin extending outwardly, and when the propeller rotates clockwise when viewed from the rear of the ship, or when the propeller rotates left when viewed from the rear of the ship, the upper side of the starboard side Then, the extending direction of the outer fins is directed upward from the extending direction of the corresponding inner fin.

The inner fin and the outer fin fixed to the duct located in front of the propeller ship promote the pre-turning upstream of the propeller to improve the propeller efficiency.
Since the inner fin and the outer fin are fixed to the duct, the inner fin and the outer fin can be easily installed via the duct even if the inner fin and the outer fin have different installation angles.
The upstream side of the propeller becomes a complicated flow field due to the hull shape such as bossing. For example, in a plane orthogonal to the propeller rotation axis, the flow from the upper side to the lower side is mainly on the inner peripheral side centered on the propeller rotation axis, and the flow from the lower side to the upper side is mainly along the circumferential direction on the outer peripheral side. It becomes. The inventors have found that the installation angle between the inner fin and the outer fin can be optimized by paying attention to this flow field.
Specifically, in the case of propeller clockwise rotation, on the port side (in the case of propeller counterclockwise, on the starboard side), the extending direction in the radial direction of the outer fin is set in the radial direction of the corresponding inner fin. It was made to face upwards from the extending direction. Thereby, a flow can be changed in the direction which opposes the propeller which rotates upwards from the downward direction.
In the case of propeller right rotation, the port side upper side (in the case of propeller left rotation, on the starboard side) is, for example, an area above the horizontal line passing through the propeller rotation axis when viewed from the rear of the ship. Means.
Moreover, it is good also as combining the above-mentioned invention regarding the installation angle of an inner fin and an outer fin, and the above-mentioned invention which made the installation position with respect to the duct of an inner fin and an outer fin different.

Furthermore, in the fin unit device according to one aspect of the present invention, the duct has a wing-shaped longitudinal section in which a cord length direction is provided so as to incline from the upstream side toward the downstream side toward the rotation axis.

Since the duct has a wing-shaped longitudinal section with the cord length direction inclined to the propeller rotation axis side from the upstream side to the downstream side, the propulsive force is obtained by the flow flowing into the duct Can do.

Furthermore, in the fin unit device according to one aspect of the present invention, the cord length below the duct is smaller than the cord length above the duct.

Below the duct, the flow field on the inner peripheral side is directed downward, so that even in the case of a wing-shaped duct, flow separation is likely to occur and it is difficult to obtain a driving force. Therefore, the cord length below the duct is made shorter than the upper one so as not to become more resistant. Note that the installation angle below the duct may be set different from that above the duct so that the installation angle does not become more resistance.
The lower part of the duct means, for example, a region below a horizontal line passing through the propeller rotation axis when the duct is viewed from the rear of the ship.

Furthermore, in the fin unit device according to one aspect of the present invention, a duct missing portion in which the duct is partially missing is provided below the duct.

The lower part of the duct was provided with a part of the duct missing part that was partly missing to form a region where no duct was provided. Thereby, the resistance of the duct in the region where the flow separation and the flow velocity in the direction of the propeller rotation axis are large can be reduced.

Furthermore, in the fin unit device according to one aspect of the present invention, the center position when the duct is viewed from the rear of the hull is different from the rotation axis.

The upstream side of the propeller becomes a complicated flow field due to the hull shape such as bossing. For this reason, the duct has a region where thrust is generated as described above, and there is also a region where the duct itself becomes a resistance. Therefore, by installing the center position of the duct at a position different from the propeller rotation axis, the performance of the duct can be effectively exhibited.
For example, at a position where thrust can be generated, such as above the duct, the duct is positioned at a position where thrust can be effectively generated with respect to the flow. The duct is positioned along the line to reduce the resistance. In this case, the cross-sectional shape of the duct is not limited to a circle, but may be an ellipse, an oval, or a shape with a part cut away. The center position in the shape when it is not circular means the centroid.
When the flow field on the upstream side of the propeller changes due to the influence of the rotation of the propeller, the center position of the duct is set accordingly. For example, the center position of the duct may be set so as to be shifted from the vertical line passing through the propeller rotation axis in the propeller rotation direction.

In addition, a ship according to an aspect of the present invention includes a propeller that rotates about a rotation axis, the propeller rotatably supported, a boshing provided in front of the propeller ship, and the above-described boshing. One of the fin unit devices described above is provided.

Since the inner and outer fins are appropriately installed according to the flow field upstream of the propeller, the propulsion performance of the ship can be improved by improving the flow field upstream of the propeller.

It is the side view which showed the stern part of the ship which concerns on 1st Embodiment of this invention. It is a front view at the time of seeing the fin unit device concerning a 1st embodiment of the present invention from a ship back. It is the side view which showed the inner side fin and outer side fin which looked at the fin unit apparatus of FIG. 2 from the port side. It is the side view which showed the inner side fin and outer side fin which looked at the fin unit apparatus of FIG. 2 from the starboard side. It is the figure which showed the flow field of the propeller upstream from the ship back. It is a front view at the time of seeing the fin unit apparatus concerning a 2nd embodiment of the present invention from a ship back. It is a front view at the time of seeing the fin unit apparatus concerning a 3rd embodiment of the present invention from a ship back. It is the longitudinal cross-sectional view which showed the duct which concerns on 4th Embodiment. It is the longitudinal cross-sectional view which showed the duct which concerns on 5th Embodiment. It is a front view at the time of seeing the duct concerning a 6th embodiment from a ship back. It is a front view at the time of seeing the duct concerning a 7th embodiment from a ship back. It is a front view of the duct which showed the modification of FIG. It is a front view of the duct which showed the other modification of FIG.

[First Embodiment]
FIG. 1 shows a stern portion of a ship 1 according to the first embodiment of the present invention. A stern portion is provided with a bossing 11 and a stern overhang portion 12. The bossing 11 is located on the upstream side of the propeller, and rotatably supports the propeller 10 so that the propeller 10 for propulsion can rotate about the rotation axis L1. The stern overhang portion 12 is provided above the propeller 10.

The fin unit device 20 is attached to the bossing 11. The fin unit device 20 generates a swirling flow in the direction opposite to the rotation direction of the propeller 10 at the time of forward movement, thereby improving the propeller efficiency.

FIG. 2 shows a front view of the fin unit device 20 as viewed from the rear. As shown in the coordinate axis at the lower right of FIG. 2, the traveling direction of the ship is the x axis, the horizontal direction orthogonal to the x axis is the y axis, and the vertical direction orthogonal to the x axis is the z axis (hereinafter referred to as “x axis”). the same).

The fin unit device 20 includes a duct 22, an inner fin 24 positioned on the inner peripheral side of the duct 22, and an outer fin 25 positioned on the outer peripheral side of the duct 22.

The duct 22 has a cylindrical shape, and the central axis of the duct 22 coincides with the rotation axis L1 of the propeller 10. The radius of the duct 22 is 0.3R or more and 0.9R or less, where R is the radius of the propeller 10.

The inner fin 24 has an inner end fixed to the boshing 11 and an outer end fixed to the inner peripheral surface of the duct 22. The inner fin 24 extends in the radial direction around the rotation axis L1. As shown in FIG. 3 and FIG. 4, the cross section of the inner fin 24 has a wing shape, and is disposed so that the wing tip faces the ship front side and the wing rear end faces the ship rear.

As shown in FIG. 2, the outer fin 25 has an inner end fixed to the outer peripheral surface of the duct 22 and an outer end being a free end. The outer end portion of the outer fin 25 is disposed at a position equivalent to the outer peripheral diameter D <b> 1 of the propeller 10. The outer fins 25 extend in the radial direction about the rotation axis L <b> 1 so as to coincide with the extending direction of the corresponding inner fin 24. As shown in FIGS. 3 and 4, the cross section of the outer fin 25 has a wing shape, and is arranged so that the wing tip faces the ship front side and the wing rear end faces the ship rear.

In the present embodiment, six pairs of inner fins 24 and outer fins 25 extending in the same radial direction are provided. Specifically, three pairs of lower fins 24a and 25a, middle fins 24b and 25b, and upper fins 24c and 25c are provided on the port side, and lower fins 24d and 25d and middle fins are provided on the starboard side. Three pairs of 24e and 25e and upper fins 24f and 25f are provided. The pairs of fins 24 and 25 are provided symmetrically with respect to the vertical line V passing through the rotation axis L1, but the positions thereof can be changed as appropriate.
The middle fins 24b, 25b, 24e, and 25e extend in the horizontal line H direction. The lower fins 24a, 25a, 24d, and 25d and the upper fins 24c, 25c, 24f, and 25f are distributed to the target in the extending direction (horizontal line H direction) of the middle fins 24b, 25b, 24e, and 25e. Has been placed. However, the present invention is not limited to these fin arrangements.

As described above, since the inner fin 24 and the outer fin 25 are respectively fixed to the duct 22, the inner fin 24 and the outer fin 25 can be easily installed via the duct 22 even when the inner fin 24 and the outer fin 25 have different installation angles as will be described later. It can be installed in.

The propeller 10 rotates clockwise as viewed from the rear of the ship, as indicated by an arrow A1 in FIG.

FIG. 3 shows the inner fin 24 and the outer fin 25 as viewed from the port side. In the same figure, as shown by arrow A2, the water flow flows from right to left. The inner fins 24 and the outer fins 25 are arranged with the wing-shaped ventral side down and the dorsal side up. The inner fin 24 is disposed with an installation angle θi with respect to the reference plane P1 including the rotation axis L1 (see FIG. 2). The outer fins 25 are arranged with an installation angle θo with respect to the reference plane P2 including the rotation axis L1 (see FIG. 2). Then, on the port side, the relationship between these installation angles θi and θo is as follows.
θi> θo (1)

FIG. 4 shows the inner fin 24 and the outer fin 25 as viewed from the starboard side. In the figure, as indicated by an arrow A3, the water flow flows from right to left. The inner fins 24 and the outer fins 25 are arranged with the wing-shaped belly side up and the back side down. The inner fin 24 is disposed with an installation angle θi with respect to the reference plane P1 including the rotation axis L1 (see FIG. 2). The outer fins 25 are arranged with an installation angle θo with respect to the reference plane P2 including the rotation axis L1 (see FIG. 2). And on the starboard side, the relationship between these installation angles θi and θo is expressed by the following equation.
θi <θo (2)

The effects of this embodiment having the above-described configuration will be described below.
The upstream side of the propeller 10 becomes a complicated flow field as shown in FIG. 5 due to the shape of the boshing 11 and the upstream side and the surrounding hull shape reaching the boshing 11. This figure shows the flow field on the upstream side of the propeller 10 as seen from the rear of the ship as in FIG. In the figure, a horizontal line H and a vertical line V passing through the rotation axis L1 are shown. A solid line drawn like a contour line shows an isovelocity line in the direction of the rotation axis L1 (perpendicular to the paper surface), and the flow velocity is smaller on the inner circumference side closer to the rotation axis L1 and higher on the outer circumference side. A plurality of arrows indicate the flow direction of the water flow in a plane orthogonal to the rotation axis L1 (in the yz plane).

As can be seen from the figure, the flow from the upper side to the lower side is mainly on the inner peripheral side around the rotation axis L1, and the flow from the lower side to the upper side is mainly along the circumferential direction on the outer peripheral side. Further, the region indicated by reference sign S1 is located below the rotation axis L1 and on the outer peripheral side, and is a region where the flow velocity in the direction of the rotation axis L1 is large due to the influence of the flow outside the hull.

As shown in the above equation (1), in the case of propeller clockwise rotation, the relationship between the installation angle θi of the inner fin 24 and the installation angle θo of the outer fin 25 is θi> θo on the port side. The reason is as follows.
In the case of propeller right rotation, on the port side, as shown in FIG. 5, the flow field on the inner peripheral side is mainly the flow from the upper side to the lower side, and is in the direction facing the propeller 10 that rotates from the lower side to the upper side. . For this reason, the installation angle θi of the inner fin 24 is increased so as to promote the flow from the upper side to the lower side. The installation angle θi is set to be an angle of attack along the inflowing flow. In this case, the angle of attack is set to, for example, 0 ° to 20 ° C., preferably 0 ° to 15 °.

On the other hand, the flow field on the outer peripheral side is mainly from the bottom to the top, and is in the same direction as the propeller 10 that rotates from the bottom to the top. For this reason, it is preferable that the outer fins 25 have an installation angle that changes the flow downward. However, since the flow velocity in the direction of the rotation axis L1 of the propeller 10 is larger on the outer peripheral side than on the inner peripheral side, the outer fin 25 becomes resistance to flow if the installation angle θo of the outer fin 25 is set so as to obtain a large angle of attack. Therefore, it is not preferable. Therefore, as shown in Expression (1), the installation angle θo of the outer fin 25 is set smaller than the installation angle θi of the inner fin 24.
As described above, the flow field on the upstream side of the propeller 10 is improved on the inner peripheral side and the outer peripheral side, and the propulsion performance of the ship 1 can be improved.

The inner fin 24 and the outer fin 25 were installed with the wing-shaped ventral side facing downward. Thereby, the flow direction can be effectively changed from the upper side to the lower side using the ventral shape, and the flow field can be further improved.

Further, as shown in the above equation (2), when the propeller 10 rotates clockwise, the relationship between the installation angle θi of the inner fin 24 and the installation angle θo of the outer fin 25 is expressed as θi <θo on the starboard side. did. The reason is as follows.
As shown in FIG. 5, the flow field on the inner peripheral side mainly flows from the upper side to the lower side, and is in the same direction as the propeller 10 that rotates from the upper side to the lower side. For this reason, the installation angle θi is increased so that the inner fin 24 changes the flow upward.
On the other hand, the flow field on the outer peripheral side is mainly a flow from the lower side to the upper side, and is in a direction facing the propeller 10 rotating from the lower side to the upper side. For this reason, the installation angle θo of the outer fin 25 is increased so as to promote the flow from the lower side to the upper side. The installation angle θo is set to be an angle of attack along the inflowing flow. In this case, the angle of attack is set to, for example, 0 ° to 20 ° C., preferably 0 ° to 15 °.
From the above, as shown in Expression (2), the installation angle θo of the outer fin 25 is set larger than the installation angle θi of the inner fin 24.

The inner fin 24 and the outer fin 25 were installed with the wing-shaped ventral side facing upward. Thereby, the flow direction can be effectively changed from the lower side to the upper side using the ventral shape, and the flow field can be further improved.

In addition, although this embodiment demonstrated on the assumption of the propeller clockwise, this embodiment is applicable also in the case of a propeller counterclockwise. Specifically, what is on the starboard side when the propeller is clockwise corresponds to the starboard side when the propeller is counterclockwise, and what is on the starboard side when the propeller is clockwise corresponds to the port side on the left side of the propeller . The same applies to the following embodiments.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG.
The present embodiment is different from the first embodiment in the arrangement of the inner fins 24 and the outer fins 25, and is otherwise the same. Accordingly, only the differences will be described below, and the same components are denoted by the same reference numerals and description thereof is omitted.

As shown in FIG. 6, there is a pair in which the corresponding outer fin 25 is not provided at a position corresponding to the extending direction of the inner fin 24.

Specifically, there is no corresponding outer fin 25 in the extending direction of the lower inner fin 24a and the lower inner fin 24d of the starboard. Thereby, it is avoided that it becomes resistance by not providing the outer fin 25 in the position where the flow velocity in the direction of the rotation axis L1 is large and on the outer peripheral side. Thus, it is preferable not to provide the outer fins 25 below the duct 22, that is, in a region below the horizontal line H passing through the rotation axis L1.

Further, a corresponding outer fin 25b is provided at a position B1 shifted upward from the extending direction of the inner fin 24b in the middle stage of the port side. That is, the inner end of the outer fin 25 b is fixed to the duct 22 above the position where the outer end of the corresponding inner fin 24 b is fixed to the duct 22. This is because a larger flow velocity in the direction of the rotation axis L1 can be avoided in the upper region, and the effect of improving the flow field by providing the outer fins 25b in this region is greater.

On the other hand, corresponding outer fins 25c and 25f are provided in the extending direction of the upper inner fin 24c on the port side and the inner fin 24f on the upper side of the starboard. This arrangement is the same as in the first embodiment.

Note that the installation angles θi and θo of the fins 24 and 25 are determined according to the flow field, as in the first embodiment.
Thus, in this embodiment, the number of the outer fins 25 is smaller than the number of the inner fins 24, and the number of the respective fins is different.

According to this embodiment, there exist the following effects.
By providing the outer fins 25 at positions different from the extending directions of the corresponding inner fins 24, the inner fins 24 and the outer fins 25 are positioned appropriately at the inner peripheral side and the outer peripheral side, which have different flow fields. Can be installed. Thereby, the flow field upstream of the propeller is improved on the inner peripheral side and the outer peripheral side, and the propulsion performance can be improved.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIG.
This embodiment differs from each of the above embodiments in the arrangement of the inner fins 24 and the outer fins 25, and the others are the same. Accordingly, only the differences will be described below, and the same components are denoted by the same reference numerals and description thereof is omitted.

As shown in FIG. 7, the extending direction in the radial direction of the middle outer fin 25b on the port side and the outer fin 25c on the upper side of the port side is longer than the extending direction in the radial direction of the corresponding inner fins 24b and 24c. It faces upwards.

The outer fin 25b on the middle side of the port side is fixed to the duct 22 at a position B1 above the extending direction of the corresponding inner fin 24b, and above the horizontal line H that is the extending direction of the corresponding inner fin 24b. It is arranged to face.
The outer fin 25c at the upper end of the port side is fixed at the same circumferential position as the position where the corresponding inner fin 24c is fixed to the duct 22, while the fixed position with respect to the duct 22 is used as a boundary to the inner fin 24c. On the other hand, it is arranged in a state bent upward.

The starboard outer fins 25e and 25f are provided in the same extending direction as the corresponding inner fins 243 and 24f, as in the first embodiment.

By adopting such a configuration, the following operational effects can be obtained.
Since the extending direction of the outer fins 25b and 25c is directed upward from the extending direction of the corresponding inner fins 24b and 24c, the flow is directed in a direction opposite to the propeller 10 that rotates upward from below on the port side. Can be changed. Thereby, the propeller efficiency can be improved by further improving the flow field above the port side.
The upper side on the port side means a region above the horizontal line H passing through the rotation axis L1.
The invention of this embodiment may be combined with the inventions of the above-described embodiments.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described with reference to FIG.
The present embodiment relates to the structure of the duct 22 shown in each of the above embodiments, and the others are the same. Accordingly, only the differences will be described below, and the same components are denoted by the same reference numerals and description thereof is omitted.

FIG. 8 shows a longitudinal sectional view of the duct 22. In the same figure, as shown by arrow A4, the water flow flows from right to left.
The longitudinal section of the duct 22 has a wing shape. The cord length direction is provided so as to incline from the upstream side toward the downstream side toward the rotation axis L1. That is, the opening on the downstream side is smaller than the opening on the upstream side of the duct 22. Further, the wing-shaped belly side is provided so as to face the inner peripheral side (rotation axis L1 side).

According to this embodiment, there exist the following effects.
Since the duct 22 has a wing-shaped longitudinal section in which the cord length direction is inclined so as to be inclined toward the rotation axis L1 from the upstream side toward the downstream side, the propulsive force is generated by the flow flowing into the duct 22. Obtainable. That is, above the duct 22, the water flow that flows into the inner peripheral side of the duct 22 generates lift F <b> 1 on the flank side of the wing shape. The component force of the rotational axis L1 of the lift force F1 becomes a propulsive force.

[Fifth Embodiment]
Next, a fifth embodiment of the present invention will be described with reference to FIG.
This embodiment is different in shape from the duct of the fourth embodiment, but is otherwise the same. Accordingly, only the differences will be described below, and the same components are denoted by the same reference numerals and description thereof is omitted.

As shown in FIG. 9, the cord length below the duct 22 is smaller than the cord length above the duct 22. That is, the opening position on the downstream side of the duct 22 coincides with the upper and lower sides of the duct 22 in the direction of the rotation axis L1, but the opening position on the upstream side of the duct 22 is lower than the upper side of the duct 22. It is located on the downstream side.

According to this embodiment, there exist the following effects.
Below the duct 22, as shown in FIG. 5, the flow field on the inner peripheral side is directed downward, so that even the wing-shaped duct 22 may cause separation of the flow and obtain a propulsive force. It's hard to be done. Therefore, the cord length below the duct 22 is made shorter than the upper one so as not to become more resistant.
Note that the installation angle below the duct 22 may be set different from that above the duct 22 so that the installation angle is less resistant.

[Sixth Embodiment]
Next, a sixth embodiment of the present invention will be described with reference to FIG.
This embodiment is different in shape from the ducts of the fourth embodiment and the fifth embodiment, but is otherwise the same. Accordingly, only the differences will be described below, and the same components are denoted by the same reference numerals and description thereof is omitted.

As shown in FIG. 10, below the duct 22, a duct missing portion 22 a in which the duct 22 is partially missing is provided. That is, the duct 22 does not exist between the lower inner fins 24a and 24d. Therefore, the cross-sectional shape of the duct 22 is a C shape having an opening below.

According to this embodiment, there exist the following effects.
Below the duct 22, a partially missing duct portion 22 a is provided to form a region where the duct 22 is not provided. Thereby, the resistance of the duct 22 in the region where the flow separation and the flow velocity in the direction of the rotation axis L1 are large can be reduced.
In addition, this embodiment can be combined with each embodiment mentioned above.

[Seventh Embodiment]
Next, a seventh embodiment of the present invention will be described with reference to FIGS.
This embodiment is different in shape from the ducts of the fourth to sixth embodiments, but is otherwise the same. Accordingly, only the differences will be described below, and the same components are denoted by the same reference numerals and description thereof is omitted.

FIG. 11 is a diagram showing the duct 22 superimposed on the flow field shown in FIG. As shown in the figure, the duct center C1 is located at a position different from the rotation axis L1, and is provided above the rotation axis L1. The cross-sectional shape of the duct 22 is an elliptical shape having a long axis that coincides with the vertical line V. The duct center C1 is an elliptical centroid.

The upper half of the duct 22 is installed in a region that flows from above toward the duct center C1. Thereby, a thrust can be more effectively generated in the duct 22.
The lower half of the duct 22 has a long axis of the ellipse directed in the direction of the vertical line V, and the right and left walls in FIG. Yes. Further, by directing the short axis of the ellipse in the direction of the horizontal line H, the region of the lower end portion of the duct 22 is shortened to reduce the resistance.

FIG. 12 shows a modification of FIG. As shown in the figure, the duct center C1 is provided below the rotation axis L1. The elliptical shape of the cross section of the duct 22 is provided with a short axis corresponding to the vertical line V, and a long axis is provided along the horizontal line H direction.
The upper half of the duct 22 is installed in a region that flows from above toward the duct center C1. Thereby, a thrust can be more effectively generated in the duct 22.
The lower half of the duct 22 is provided so that the water flow is deflected in the left-right direction (horizontal direction) from the downward flow and coincides with the upward flow. Thereby, the resistance of the duct 22 can be reduced.

11 and 12, the cross-sectional shape of the duct 22 is an ellipse. However, the shape is not limited to this, and a shape in which a plurality of curvatures are combined so as to be in an appropriate position according to the flow field. Also good.

FIG. 13 shows another modification. As shown in the figure, the duct center C1 is located above and to the right of the rotation axis L1. This corresponds to the case where the flow field on the upstream side of the propeller 10 is shifted by a predetermined angle in the right direction indicated by the arrow A5 about the rotation axis L1 due to the influence of the rotation of the propeller 10. That is, the horizontal line of the flow field is shifted to the position indicated by the symbol H ′, and the vertical line is shifted to the position indicated by the symbol V ′. Thereby, the duct 22 can be installed in an appropriate position according to the flow field.
In addition, this embodiment can be combined with each embodiment mentioned above.

DESCRIPTION OF SYMBOLS 1 Ship 10 Propeller 11 Bossing 12 Stern overhang part 20 Fin unit apparatus 22 Duct 24 Inner fin 25 Outer fin L1 Rotation axis D1 Propeller outer diameter A1 Propeller rotation direction A2, A3, A4 Water flow direction H Horizontal line V Vertical line

Claims (11)

1. A duct located on the front side of the ship of the propeller and fixed to the boshing side so as to surround the rotation axis of the propeller;
   An inner fin that has an outer end fixed to the inner peripheral side of the duct and extends radially inward toward the rotation axis;
   An outer fin located in the extending direction of the inner fin and having an inner end fixed to the outer peripheral side of the duct and extending radially outward;
   With
   At least a pair of the inner fin and the outer fin are:
   When the propeller is right-handed when viewed from the rear of the ship, on the port side, or when the propeller is left-handed when viewed from the rear of the ship, on the starboard side,
   When the angle of attack is formed with respect to the inflowing water, the installation angle of the inner fin with respect to the reference plane including the rotation axis is θi, and the installation angle of the outer fin with respect to the reference plane is θo,
   θi> θo
   Fin unit device.
2. A duct located on the front side of the ship of the propeller and fixed to the boshing side so as to surround the rotation axis of the propeller;
   An inner fin that has an outer end fixed to the inner peripheral side of the duct and extends radially inward toward the rotation axis;
   An outer fin located in the extending direction of the inner fin and having an inner end fixed to the outer peripheral side of the duct and extending radially outward;
   With
   At least a pair of the inner fin and the outer fin are:
   On the starboard side when the propeller is rotated clockwise as viewed from the rear of the ship, or on the port side when the propeller is rotated left when viewed from the rear of the ship,
   When the angle of attack is formed with respect to the inflowing water, the installation angle of the inner fin with respect to the reference plane including the rotation axis is θi, and the installation angle of the outer fin with respect to the reference plane is θo,
   θi <θo
   Fin unit device.
3. A duct located on the front side of the ship of the propeller and fixed to the boshing side so as to surround the rotation axis of the propeller;
   An inner fin that has an outer end fixed to the inner peripheral side of the duct and extends radially inward toward the rotation axis;
   An outer fin having an inner end fixed to the outer peripheral side of the duct at a position different from the extending direction of the inner fin and extending radially outward;
   A fin unit device.
4. The fin unit device according to claim 3, wherein the outer fin is not provided below the duct.
5. When the propeller is right-handed when viewed from the rear of the ship, on the port side, or when the propeller is left-handed when viewed from the rear of the ship, on the starboard side,
   The fin unit device according to claim 3 or 4, wherein the inner end portion of the outer fin is fixed to the duct at a position above the corresponding inner fin.
6. A duct located on the front side of the ship of the propeller and fixed to the boshing side so as to surround the rotation axis of the propeller;
   An inner fin that has an outer end fixed to the inner peripheral side of the duct and extends radially inward toward the rotation axis;
   An outer fin located in the extending direction of the inner fin and having an inner end fixed to the outer peripheral side of the duct and extending radially outward;
   With
   When the propeller is rotating clockwise when viewed from the rear of the ship, or above the port side when the propeller is rotating left when viewed from the rear of the ship,
   A fin unit device in which the extending direction of the outer fin is directed upward with respect to the extending direction of the corresponding inner fin.
7. The fin unit device according to any one of claims 1 to 6, wherein the duct has a wing-shaped longitudinal section provided with a cord length direction so as to be inclined toward the rotation axis from the upstream side toward the downstream side.
8. The fin unit device according to claim 7, wherein the cord length below the duct is smaller than the cord length above the duct.
9. The fin unit device according to claim 7 or 8, wherein a duct defect part in which the duct is partially broken is provided below the duct.
10. The fin unit device according to any one of claims 7 to 9, wherein a center position when the duct is viewed from the rear of the hull is different from the rotation axis.
11. A propeller that rotates about a rotation axis;
    The propeller is rotatably supported, and a boshing provided in front of the ship of the propeller;
    The fin unit device according to any one of claims 1 to 10, which is provided in the bossing;
    Ship equipped with.

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