JP2019209879A - Vessel propeller and processing method for the same - Google Patents

Abstract

To provide a vessel propeller and a processing method for the same capable of improving sound depression effect by depressing exciting force in each position by preventing separation vortex from connecting by being aligned in a radius direction.SOLUTION: A vessel propeller including a hub rotated around an axial line and a plurality of wings 14 provided at equivalent angle intervals in circumferential direction of the hub and having a positive pressure surface and a negative pressure surface 14B positioned on an opposite side of the positive pressure surface has a first inclination surface 18A inclining in the wing chord direction against the positive pressure surface from the positive pressure surface side to the negative pressure surface 14B side and a second inclination surface 18B inclining in the wing chord direction to the negative pressure surface 14B from the negative pressure surface 14B side to the positive pressure surface side formed continuously and alternately along an end edge side of the wing 14 in the radius direction.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a marine propeller and a processing method thereof.

  In a rotating marine propeller, separation vortices are alternately generated from the pressure side and the suction side located at the trailing edge of the wing. Due to the alternately generated separation vortices, an excitation force acts on the trailing edge side of the blade, and resonates in accordance with the natural frequency of the blade, thereby generating blade vibration sound called sound.

  For example, this sounding sound may cause a problem in a survey ship that operates an acoustic measurement device or a ship that requires quietness.

  Therefore, in order to suppress this sound, Japanese Patent Application Laid-Open No. H10-228667 cuts one side of the trailing edge of the blade to incline so that the generation period of the separation vortex does not coincide with the natural frequency of the blade. The noise prevention processing is disclosed as a conventional method.

  Further, in Patent Document 1, in the wing surface of the trailing edge, in the radial direction of the wing, the tip side and the boss side are provided with a switching zone in the middle and processed from opposite surfaces, and in the switching zone, A noise prevention process is disclosed in which sound generation can be prevented and the rotation speed of the propeller is not lowered by processing from both sides so as to smoothly connect the tip side section and the boss side section.

JP 2001-247088 A

  However, in the method disclosed in Patent Document 1, since the blade surface to be processed is continuous in a certain radial section (for example, a tip-side section) at the trailing edge of the blade, the separation vortex is generated in the radial direction of the blade. It is easy to align the generation cycle. As a result, the separation vortex is connected in the radial direction, and as a result, the excitation force acting on the trailing edge side of the blade is increased, and there is a possibility that sound is still generated.

  The present invention has been made in view of such circumstances, and it is possible to improve the sound suppression effect by preventing the separation vortices from being aligned in the radial direction and suppressing the excitation force at each position. An object of the present invention is to provide a marine propeller that can be used and a processing method thereof.

In order to solve the above problems, the marine propeller and the processing method thereof according to the present invention employ the following means.
That is, a marine propeller according to an aspect of the present invention includes a hub that is rotated around an axis, a pressure surface that is provided at equal angular intervals in the circumferential direction of the hub, and a suction surface that is located on the opposite side of the pressure surface. A marine propeller having a plurality of blades having a first inclined surface inclined in a chord direction with respect to the pressure surface from the pressure surface side toward the suction surface side, and the suction surface side Second inclined surfaces that incline in the chord direction with respect to the suction surface toward the pressure surface side are formed alternately and continuously along the trailing edge side of the blade in the radial direction.

In the marine propeller according to this aspect, the first inclined surface and the second inclined surface are formed alternately and continuously along the radial direction at the trailing edge of the wing. According to this, the starting point and timing of the separation vortex discharged from the pressure surface side and the suction surface side of the first inclined surface and the second inclined surface can be varied in the radial direction of the blade. Therefore, it is possible to prevent the separation vortices emitted from the first inclined surface and the second inclined surface from being aligned in the radial direction and to be connected to each other, and thus act on the trailing edge side of the blade on which the first inclined surface and the second inclined surface are formed. The excitation force can be suppressed, and the sound suppression effect can be improved. In addition, since the first inclined surface and the second inclined surface are alternately and continuously formed, when the blade is viewed in plan, the contour of the trailing edge of the blade becomes a smooth curve, and the first inclined surface and the second inclined surface It is almost the same as the outline when no surface is formed. Therefore, since the wing area is hardly reduced, the risk of lowering the thrust is small.
Note that when the first inclined surface (or the second inclined surface) is focused on and cut in the direction of the chord and viewed in cross section, the chord of the separation vortex released from the pressure surface side and the suction surface side due to the inclination. It goes without saying that the starting position in the direction can be made different, and the separation vortex can be prevented from being alternately generated from the pressure surface side and the suction surface side. As a result, it is possible to prevent the excitation force from acting on the trailing edge of the wing, thereby obtaining a sound reduction effect.

  In the marine propeller according to one aspect of the present invention, the radial lengths of the first inclined surface and the second inclined surface are formed by the first inclined surface and the second inclined surface, respectively. The distance between the pressure surface and the suction surface when the first inclined surface and the second inclined surface are not formed at the trailing edge of the blade corresponding to the position is set.

  According to the marine propeller according to this aspect, for example, two second inclined surfaces (or first inclined surfaces) sandwiching one first inclined surface (or second inclined surface) are prevented from being too close to each other. Parameters can be shown. If two second inclined surfaces (or first inclined surfaces) sandwiching the first inclined surface (or second inclined surface) are too close to each other, the first inclined surface (or second inclined surface) is changed. There is a possibility that the separation vortices released from the pressure surface side and the suction surface side of the two second inclined surfaces (or first inclined surfaces) sandwiched may be aligned and connected in the radial direction, so that a sufficient noise suppression effect can be obtained. There is a risk of not.

  In the marine propeller according to one aspect of the present invention, each of the first inclined surface and the second inclined surface in the radial direction is a length from the axis to the blade tip in the radial direction. It is supposed to be 10% or less of the propeller radius.

  According to the marine propeller according to this aspect, for example, a parameter that prevents the length of one first inclined surface (or second inclined surface) in the radial direction from becoming too large can be indicated. If the length of the first inclined surface (or second inclined surface) in the radial direction becomes too large, the first inclined surface (or second inclined surface) is released from the pressure surface side and the suction surface side of the first inclined surface (or second inclined surface). Peeling vortices may be connected together in the radial direction on the pressure surface side and the suction surface side of the first inclined surface (or second inclined surface) in the radial direction, thereby obtaining a sufficient noise suppression effect. There is a risk of not being able to.

  In the marine propeller according to one aspect of the present invention, the lengths of the first inclined surface and the second inclined surface in the chord direction are determined by the first inclined surface and the second inclined surface, respectively. The distance between the pressure surface and the suction surface when the first inclined surface and the second inclined surface are not formed at the trailing edge of the blade corresponding to the formed position is set to be equal to or greater than the distance between the pressure surface and the suction surface.

  According to the marine propeller according to this aspect, for example, the inclination starting point and the trailing edge of one first inclined surface (or second inclined surface) are too close to the chord direction, that is, the pressure surface side and the negative surface side. Parameters can be shown that prevent the origin of the separation vortex emitted from each of the pressure side from being too close to the chord direction. If the starting point of the separation vortex released from each of the pressure surface side and the suction surface side is too close to the chord direction on the first inclined surface (or second inclined surface), the first inclined surface ( Alternatively, the separation vortices released from the pressure surface side and the suction surface side of the second inclined surface are likely to be alternately generated, and there is a possibility that the sound suppression effect due to the inclination that should originally be obtained cannot be obtained.

  In the marine propeller according to one aspect of the present invention, the lengths of the first inclined surface and the second inclined surface in the chord direction are determined by the first inclined surface and the second inclined surface, respectively. It is set to 10% or less of the chord length at the radial position of the wing corresponding to the formed position.

  According to the marine propeller according to this aspect, for example, the inclination starting point and the trailing edge of one first inclined surface (or second inclined surface) are excessively separated in the chord direction, that is, the first inclined surface. A parameter that prevents the angle at the tilt start point of (or the second tilted surface) from being too gentle can be indicated. If the angle of the first inclined surface (or second inclined surface) at the starting point of the slope becomes excessively gentle, there is a possibility that no separation vortex will occur at the starting point of the tilt, and the sound due to the inclination that should originally be obtained. Sound suppression effect may not be obtained.

  A processing method of a marine propeller according to an aspect of the present invention includes a hub that is rotated around an axis, and a suction surface that is provided at equal angular intervals in the circumferential direction of the hub and that is positioned on the opposite side of the pressure surface and the pressure surface. A marine propeller processing method comprising: a first inclined surface inclined in a chord direction with respect to the pressure surface from the pressure surface side toward the suction surface side; and Forming second inclined surfaces that incline in the chord direction with respect to the suction surface from the suction surface side toward the pressure surface side alternately and continuously along the radial direction at the trailing edge of the blade; including.

  According to the marine propeller and the processing method thereof according to the present invention, it is possible to improve the sound suppression effect by preventing the separation vortices from being aligned and connected in the radial direction and suppressing the excitation force at each position.

1 is a perspective view of a marine propeller according to an embodiment of the present invention. It is a top view of the wing | blade with which a ship propeller is provided. It is an enlarged view of the A section shown in FIG. It is a longitudinal cross-sectional view in the cutting line II shown in FIG. It is a longitudinal cross-sectional view in the cutting line II-II shown in FIG. It is a longitudinal cross-sectional view of the wing | blade with which a ship propeller is provided. It is the figure which showed the relationship between the propeller radial direction position and chord length in the wing | blade with which a marine propeller is provided.

  Hereinafter, a marine propeller according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows a marine propeller 1 (hereinafter simply referred to as “propeller 1”) of the present embodiment. The propeller 1 is attached to the rear end of the ship and is used for propulsion.

  The propeller 1 includes a hub 12 that is rotated around an axis X and a plurality of blades 14. In the figure, five blades 14 are connected to the outer peripheral surface of the hub 12 at equal angular intervals in the circumferential direction. A connecting portion between the blade 14 and the hub 12 is a blade root 22.

  The hub 12 is coaxially connected to a shaft (not shown). When the shaft is rotated around the axis X by power (not shown), the hub 12 (propeller 1) connected to the shaft is rotated around the axis X. In the figure, it is rotated counterclockwise with respect to the axis X.

  The blade 14 has a pressure surface 14A and a suction surface 14B. In the drawing, the blade surface visible on the front side is the suction surface 14B, and the blade surface on the back side (back side of the paper) of the suction surface 14B is the pressure surface 14A.

  FIG. 2 shows one wing 14 among the plurality of wings 14. The other blades 14 have the same configuration as the one blade 14.

  A first inclined surface 18 </ b> A and a second inclined surface 18 </ b> B are formed on the rear edge portion 16 which is a portion on the rear edge side of the blade 14.

  Here, the first inclined surface 18A and the second inclined surface 18B will be described in detail with reference to FIGS.

  FIG. 3 which is an enlarged view of a portion A shown in FIG. 2 shows a first inclined surface 18A and a second inclined surface 18B formed on the trailing edge portion 16 of the blade 14.

  As shown in FIGS. 3 and 4, the first inclined surface 18 </ b> A is inclined with respect to the chord direction at the trailing edge 16 of the blade 14 from the pressure surface 14 </ b> A of the blade 14 toward the suction surface 14 </ b> B. Here, “inclined” refers to a shape that inclines so as to cut in the chord direction with respect to the flat pressure surface 14A. Here, the corner that is the starting point of the inclination is the inclination starting point 16b, and the end of the trailing edge is the trailing edge 16a.

  As shown in FIGS. 3 and 5, the second inclined surface 18B is inclined with respect to the chord direction at the trailing edge 16 of the blade 14 from the suction surface 14B of the blade 14 toward the pressure surface 14A. Here, “inclined” refers to a shape that is inclined so as to cut in the chord direction with respect to the curved suction surface 14B. For example, the suction surface 14B is directed from the front edge side toward the rear edge side. It does not indicate a shape that is gently inclined along the original blade surface shape as formed so as to be extrapolated. That is, with respect to the surface formed when the negative pressure surface 14B side of the trailing edge portion 16 formed with the two first inclined surfaces 18A located on both sides in the radial direction of the second inclined surface 18B is smoothly connected, the blade It refers to a shape that inclines in the chord direction. Here, the corner that is the starting point of the inclination is the inclination starting point 16b, and the end of the trailing edge is the trailing edge 16a. At this time, the angle formed by the second inclined surface 18B with respect to one direction (for example, the horizontal direction in FIG. 5) at the inclination start point 16b and the angle formed by the negative pressure surface 14B with respect to the one direction at the inclination start point 16b Will be different.

  As shown in FIG. 3, the first inclined surface 18 </ b> A and the second inclined surface 18 </ b> B described above are formed in succession alternately along the trailing edge 16 of the blade 14 in the radial direction of the blade 14. . Since the first inclined surface 18A and the second inclined surface 18B are formed alternately and continuously, when the blade 14 is viewed in plan, the outline of the blade 14 formed by each trailing edge 16a is shown in FIG. As shown, it appears to be connected smoothly.

Next, the dimensions of the first inclined surface 18A and the second inclined surface 18B will be described.
The length a in the radial direction of one first inclined surface 18A shown in FIG. 3 is such that the first inclined surface 18A at the trailing edge 16 of the blade 14 corresponding to the position where the first inclined surface 18A is formed. When not formed (the original blade surface shape described above: two-dot chain line shown in FIG. 4), the blade thickness d is preferably greater than or equal to the distance between the pressure surface 14A and the suction surface 14B. Here, the blade thickness d at the trailing edge 16 when the first inclined surface 18A is not formed is equal to the trailing edge 16a of the first inclined surface 18A and the first inclined surface 18A shown in FIG. The distance in the blade thickness direction is approximately equal to the trailing edge 16a of the adjacent second inclined surface 18B.

  Further, the length b in the radial direction of the second inclined surface 18B is such that the second inclined surface 18B is not formed in the trailing edge 16 of the blade 14 corresponding to the position where the second inclined surface 18B is formed. The blade thickness d (interval between the pressure surface 14A and the suction surface 14B) in the case (the above-described original blade surface shape: the two-dot chain line shown in FIG. 5) is preferable. Here, the blade thickness d at the trailing edge 16 when the second inclined surface 18B is not formed is equal to the trailing edge 16a of the second inclined surface 18B and the second inclined surface 18B shown in FIG. The distance in the blade thickness direction is approximately equal to the trailing edge 16a of the adjacent first inclined surface 18A.

  Moreover, it is preferable that the radial length a of the first inclined surface 18A and the radial length b of the second inclined surface 18B are 10% or less of the propeller radius. The propeller radius is equal to the radius of a circle drawn by the blade tip 20 (see FIG. 1) which is the tip of the blade 14 when the propeller 1 makes one rotation around the axis X.

  The length c of the first inclined surface 18A in the chord direction is such that the first inclined surface 18A is formed at the rear edge portion 16 of the blade 14 corresponding to the position where the first inclined surface 18A is formed. It is preferable that the blade thickness d (the distance between the pressure surface 14A and the suction surface 14B) is not less than the blade thickness d (the two-dot chain line shown in FIG. 4).

  Further, the length c of the second inclined surface 18B in the chord direction is such that the second inclined surface 18B is formed at the trailing edge 16 of the blade 14 corresponding to the position where the second inclined surface 18B is formed. It is preferable that the blade thickness d (the interval between the pressure surface 14A and the suction surface 14B) is not less than the blade thickness d (the two-dot chain line shown in FIG. 5).

  Further, the chord length c of the first inclined surface 18A is 10% or less of the chord length at the radial position of the blade 14 corresponding to the position where the first inclined surface 18A is formed. It is preferable.

  Further, the chord length c of the second inclined surface 18B is 10% or less of the chord length at the radial position of the blade 14 corresponding to the position where the second inclined surface 18B is formed. It is preferable.

  However, in the vicinity of the blade tip 20, as shown in FIG. 7, the chord length decreases rapidly, so the above-mentioned condition (the length c in the chord direction is not less than the blade thickness d and the chord length is not necessary. It is not necessary to keep 10% or less). The vicinity of the blade tip 20 is, for example, a region closer to the blade tip 20 than 90% of the propeller radial direction position (the remaining 10% region).

  Each dimension described above may vary depending on the position where the first inclined surface 18A (second inclined surface 18B) is formed, but the ratio of each dimension is maintained at an arbitrary position, that is, at a plurality of positions. It is conceivable to set the dimensions so that a similar relationship is established for each dimension. In particular, the length c in the chord direction of the first inclined surface 18A (second inclined surface 18B) at a certain position, and the blade thickness when the first inclined surface 18A (second inclined surface 18B) is not formed. When d is set so as to maintain the ratio of c and d at other positions, the angle of the trailing edge 16a (θ1 shown in FIG. 4 and θ2 shown in FIG. 5) is set to the radial position of the blade 14. It can be arranged without depending on. For example, let c be the length in the chord direction of the first inclined surface 18A at a certain position, and let d be the blade thickness when the first inclined surface 18A is not formed. In addition, the chord length of another first inclined surface 18A 'spaced from the position is c', and the blade thickness when the first inclined surface 18A 'is not formed is d'. At this time, although c ≠ c ′ and d ≠ d ′, when the dimensions are set so that c: d = c ′: d ′ is established, the angle of the trailing edge 16a is the same as that of the first inclined surface 18A and the first inclined surface 18A. It is equal to one inclined surface 18A ′. This facilitates construction management. For example, when the angle of the trailing edge 16a is measured when the blade 14 is processed, the angle at each position can be measured using the same angle cage.

According to this embodiment, the following effects can be obtained.
The first inclined surfaces 18A and the second inclined surfaces 18B are formed alternately and continuously along the radial direction at the trailing edge 16 of the blade 14. According to this, the starting point and timing of the separation vortex discharged from the pressure surface 14A side and the suction surface 14B side of the first inclined surface 18A and the second inclined surface 18B can be varied in the radial direction of the blade 14. Therefore, it is possible to prevent the separation vortices emitted from the first inclined surface 18A and the second inclined surface 18B from being aligned in the radial direction and connected to each other, so that the blade 14 in which the first inclined surface 18A and the second inclined surface 18B are formed can be prevented. The excitation force acting on the rear edge portion 16 can be suppressed, and the noise reduction effect can be improved.

  Further, since the first inclined surfaces 18A and the second inclined surfaces 18B are alternately and continuously formed, when the blade 14 is viewed in plan, the contour of the blade 14 formed by each trailing edge 16a is smooth. It is almost the same as the outline when the first inclined surface 18A and the second inclined surface 18B are not formed. Therefore, since the area of the wing 14 is hardly reduced, the risk of a drop in thrust is small.

  When the first inclined surface 18A is focused on and cut in the chord direction and viewed in cross section, the starting point in the chord direction of the separation vortex released from the pressure surface 14A side and the suction surface 14B side due to the inclination. Needless to say, the positions can be made different, and the occurrence of peeling vortices alternately from the pressure surface 14A side and the suction surface 14B side can be prevented. As a result, it is possible to prevent an excitation force from acting on the trailing edge portion 16 of the wing 14, so that a noise reduction effect can be obtained. The same applies to the second inclined surface 18B.

  Further, the length a of the first inclined surface 18A in the radial direction is such that the first inclined surface 18A is not formed at the trailing edge 16 of the blade 14 corresponding to the position where the first inclined surface 18A is formed. In this case, the blade thickness is preferably equal to or greater than d. Accordingly, it is possible to prevent two second inclined surfaces 18B sandwiching one first inclined surface 18A from being too close to each other. If the two second inclined surfaces 18B that sandwich the first inclined surface 18A are too close to each other, the pressure surface 14A side and the negative pressure surface 14B side of the two second inclined surfaces 18B that sandwich the first inclined surface 18A. There is a possibility that the separation vortices discharged from the vortex 14 are aligned and connected in the radial direction of the blade 14, and there is a possibility that a sufficient noise suppression effect cannot be obtained. The same applies to the radial length b of the second inclined surface 18B.

  Moreover, it is preferable that the length a in the radial direction of the first inclined surface 18A is 10% or less of the propeller radius. Thereby, for example, it is possible to prevent the length of one first inclined surface 18A in the radial direction from becoming too large. If the length of the first inclined surface 18A in the radial direction becomes too large, the separation vortex released from the pressure surface 14A side and the suction surface 14B side of the first inclined surface 18A becomes the first inclined surface. There is a possibility that the positive edge 14A side and the negative pressure face 14B side in 18A will be connected together in the radial direction of the rear edge portion 16, and there is a possibility that a sufficient sound suppression effect cannot be obtained. The same applies to the radial length b of the second inclined surface 18B.

  The length c of the first inclined surface 18A in the chord direction is such that the first inclined surface 18A is formed at the rear edge portion 16 of the blade 14 corresponding to the position where the first inclined surface 18A is formed. It is preferable that the blade thickness is not less than d when there is no blade. Accordingly, for example, it is possible to prevent the inclination start point 16b and the trailing edge 16a of the first inclined surface 18A from approaching too close to the chord direction, that is, φ1 shown in FIG. If φ1 is too close to a right angle, the separation vortices discharged from the pressure surface 14A side and the suction surface 14B side of the first inclined surface 18A are likely to be alternately generated, and this is due to the inclination that should originally be obtained. There is a possibility that the noise suppression effect cannot be obtained. The same applies to the length c of the second inclined surface 18B in the chord direction. In this case, φ2 shown in FIG. 5 can be prevented from approaching a right angle.

  Further, the chord length c of the first inclined surface 18A is 10% or less of the chord length at the radial position of the blade 14 corresponding to the position where the first inclined surface 18A is formed. It is preferable. According to this, for example, it is possible to prevent the inclination starting point 16b and the trailing edge 16a of the first inclined surface 18A from being separated too much in the chord direction, that is, φ1 shown in FIG. . If φ1 becomes excessively gentle, a separation vortex may not be generated at the inclination start point 16b, and there is a possibility that the noise reduction effect due to the inclination that should originally be obtained cannot be obtained. The same applies to the length c of the second inclined surface 18B in the chord direction. In this case, it is possible to prevent φ2 shown in FIG.

DESCRIPTION OF SYMBOLS 1 Propeller 12 Hub 14 Blade | wing 14A Positive pressure surface 14B Negative pressure surface 16 Trailing edge part 16a Trailing edge end 16b Inclination start point 18A First inclined surface 18B Second inclined surface 20 Blade tip 22 Blade root

Claims (6)

A hub that rotates around an axis,
A plurality of blades provided at equal angular intervals in the circumferential direction of the hub and having a pressure surface and a suction surface located on the opposite side of the pressure surface;
A marine propeller equipped with
A first inclined surface that inclines in a chord direction with respect to the pressure surface from the pressure surface side toward the suction surface side, and the blade with respect to the suction surface from the suction surface side toward the pressure surface side A marine propeller in which second inclined surfaces that incline in a chord direction are formed alternately and continuously along a trailing edge side of the wing in the radial direction. The radial length of each of the first inclined surface and the second inclined surface is:
The positive when the first inclined surface and the second inclined surface are not formed at the trailing edge of the blade corresponding to the position where the first inclined surface and the second inclined surface are formed, respectively. The marine propeller according to claim 1, wherein a distance between the pressure surface and the suction surface is equal to or greater than the distance. The radial length of each of the first inclined surface and the second inclined surface is:
The marine propeller according to claim 1 or 2, wherein the propeller radius is 10% or less of a length from the axis to the blade tip in the radial direction. The length of each of the first inclined surface and the second inclined surface in the chord direction is:
The positive when the first inclined surface and the second inclined surface are not formed at the trailing edge of the blade corresponding to the position where the first inclined surface and the second inclined surface are formed, respectively. The marine propeller according to any one of claims 1 to 3, wherein a distance between the pressure surface and the suction surface is equal to or greater than the distance. The length of each of the first inclined surface and the second inclined surface in the chord direction is:
5. The method according to claim 1, wherein the length of the chord at the radial position of the blade corresponding to the position where each of the first inclined surface and the second inclined surface is formed is 10% or less. The marine propeller described in 1. A hub that rotates about an axis,
A plurality of blades provided at equal angular intervals in the circumferential direction of the hub and having a pressure surface and a suction surface located on the opposite side of the pressure surface;
A processing method for a marine propeller equipped with
A first inclined surface that inclines in a chord direction with respect to the pressure surface from the pressure surface side toward the suction surface side, and the blade with respect to the suction surface from the suction surface side toward the pressure surface side A processing method for a marine propeller, including a step of alternately forming second inclined surfaces inclined in a chord direction along a radial direction at a rear edge of the wing.

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