JP5653699B2 - Ship frictional resistance reduction device - Google Patents

Description

  The present invention relates to a ship frictional resistance reduction device and a ship frictional resistance reduction method for reducing the frictional resistance of a ship body by blowing air.

  A technique for reducing the hull frictional resistance by covering the bottom of the ship with a bubbly flow during navigation is known.

  With reference to FIGS. 1A and 1B, the hull frictional resistance reduction device of Patent Document 1 will be described. A gas chamber 2 is provided on the bow side of the ship bottom 1. The gas chamber 2 is formed in the ship width direction. A pair of left and right gas holding plates 5 are provided from the bow to the stern along the bottom of the ship bottom. Gas is blown out from the gas chamber 2 into the water, and a bubble flow that flows backward along the ship bottom is generated. The gas holding plate 5 prevents the bubble flow from deviating to the side of the hull. In this way, the frictional resistance of the hull is reduced.

  In the hull frictional resistance reduction device of Patent Document 1, gas is blown out into the water from the gas chamber 2 provided at a deep water depth. In this hull frictional resistance reduction device, the air blowing energy is large because it is necessary to blow air into the water against high water pressure.

  Patent Document 2 discloses a hull frictional resistance reduction method for reducing air blowing energy. With reference to FIG. 2, the hull frictional resistance reduction method of Patent Document 2 will be described. In this method, the air blower 110 is disposed on the bow 102 of the hull 101 on the streamline 104 and slightly below the water line, and the bubbles 121 are caused to wrap around the ship bottom 103, so that the hull frictional resistance during navigation is obtained. Reduce. In this hull frictional resistance reduction method, the air blowing energy is reduced by providing the air blowing device 110 at a shallow water depth as compared with the case where the air blowing device 110 is provided at the deep water bottom 103.

JP 2008-114710 A Japanese Patent No. 3185047

  An object of the present invention is to provide a ship frictional resistance reduction device and a ship frictional resistance reduction method that have low air blowing energy and prevent the departure of air from the ship bottom to the side of the hull.

  The means for solving the problem will be described below using the numbers used in the (DETAILED DESCRIPTION). These numbers are added to clarify the correspondence between the description of (Claims) and (Mode for Carrying Out the Invention). However, these numbers should not be used to interpret the technical scope of the invention described in (Claims).

  The ship frictional resistance reduction device (20) according to the present invention protrudes downward from an air blowing device (30) for blowing air into the water from the bow side (11a) of the hull (10) and the bottom (13) of the hull. And a plurality of gas holding structures (40 (41 to 45)). The plurality of gas holding structures are provided along a first gas holding structure (41) provided along a port side edge portion (13a) of the ship bottom and a starboard side edge portion (13b) of the vessel bottom. A second gas holding structure (42).

  The plurality of gas holding structures are provided so as to extend in the ship length direction (X), respectively. The plurality of gas holding structures include one or more intermediate gas holding structures (43 to 45) disposed between the first gas holding structure and the second gas holding structure. The plurality of bow side end portions (41a to 45a) of the plurality of gas holding structures are arranged closer to the stern (12) as being closer to the center line (CL) of the hull.

  The ship frictional resistance reduction device (20) further includes a propeller inflow prevention structure (60) provided on the ship bottom so as to be disposed on the bow (11) side of the propeller (16). The propeller inflow prevention structure protrudes downward from the ship bottom so as to prevent air from flowing into the propeller.

  Each of the plurality of gas holding structures includes a plurality of gas holding plates (50) arranged along the ship length direction (X). The plurality of gas holding plates are arranged so that a gap (55) is provided in the ship length direction (X).

  Each of the plurality of gas holding plates includes a front edge (50a) having an R or an inclination and a rear edge (50b) having an R or an inclination.

  Each of the plurality of gas holding structures is a gas holding plate (40 (41 to 45)) extending along the ship length direction (X). The gas holding plate includes a front edge (40a (41a to 45a)) having an R or an inclination and a rear edge (40b (41b to 45b)) having an R or an inclination.

  The air blowing device includes a plurality of air blowing chambers (35A, 35B) for blowing air into outboard water, and an air supply device (31) capable of individually supplying air to the plurality of air blowing chambers. The plurality of air blowing chambers are respectively disposed at a plurality of positions having different water depths on the bow side.

  The step of blowing the air into the water from the bow side (11a) so that the air flows around the ship bottom (13) and a plurality of gas holding structures (40 (41 to 45) provided so as to protrude downward from the ship bottom are described above. A step of restricting the movement of air in the ship width direction (Y), wherein the plurality of gas holding structures includes a first gas holding structure (41) provided along a port side edge portion (13a) of the ship bottom. ) And a second gas holding structure (42) provided along the starboard side edge portion (13b) of the ship bottom.

  ADVANTAGE OF THE INVENTION According to this invention, the frictional resistance reduction apparatus of the ship and the frictional resistance reduction method of a ship with which the air blowing energy is small and the deviation | shift of the air from a ship bottom to the hull side is prevented are provided.

FIG. 1A is a side view of a ship provided with a conventional hull frictional resistance reduction device. FIG. 1B is a bottom view of a ship provided with a conventional hull frictional resistance reduction device. FIG. 2 is a side view of a conventional frictional resistance reduction type ship. FIG. 3 is a side view of the ship according to the first embodiment. FIG. 4 is a bottom view of the ship according to the first embodiment. FIG. 5 is a schematic diagram for explaining the effect of the gas holding structure according to the first embodiment. FIG. 6 shows a gas holding structure according to the second embodiment. FIG. 7 shows a gas holding structure according to a first modification of the second embodiment. FIG. 8 is a bottom view of the ship according to the third embodiment. FIG. 9 is a schematic diagram for explaining the effect at the time of rolling of the gas holding structure according to the first embodiment. FIG. 10 is a schematic diagram for explaining the effect at the time of rolling of the gas holding structure according to the third embodiment. FIG. 11 is a bottom view of a ship according to the fourth embodiment. FIG. 12 shows a gas holding structure according to the fifth embodiment. FIG. 13 is a side view of the bow portion of the ship according to the sixth embodiment. FIG. 14 is a block diagram of an air blowing device according to the sixth embodiment.

  DESCRIPTION OF EMBODIMENTS Embodiments for carrying out a ship frictional resistance reduction device and a ship frictional resistance reduction method according to the present invention will be described below with reference to the accompanying drawings.

(First embodiment)
With reference to FIG. 3, the ship which concerns on the 1st Embodiment of this invention is demonstrated. The ship includes a hull 10 and a frictional resistance reduction device 20. The hull 10 includes a bow 11, a stern 12, a ship bottom 13, and a propeller 16. The propeller 16 is provided on the stern 12. The ship length direction and the water depth direction of the hull 10 are indicated by reference signs X and Z, respectively.

  The frictional resistance reduction device 20 includes an air blowing device 30 and a plurality of gas holding structures 40 provided on the ship bottom 13. The air blowing device 30 includes an air supply device 31 and an air blowing chamber 35. The air blowing chamber 35 is disposed on the bow side 11 a as a ship side portion of the bow 10. The air supply device 31 supplies air to the air blowing chamber 35. The air blowing chamber 35 blows air into the water from the bow side 11a. The air blowing device 30 blows out air so as to wrap around the ship bottom 13 along a streamline near the bow 11. The plurality of gas holding structures 40 are provided so as to protrude downward from the ship bottom 13. Each gas holding structure 40 is formed as a single continuous gas holding plate extending in the ship length direction X from the bow side end portion 40a to the stern side end portion 40b.

  With reference to FIG. 4, the hull 10 includes a port 14 and a starboard 15. A ship width direction of the hull 10 is indicated by a symbol Y. The air blowing chambers 35 are provided on both sides. The plurality of gas holding structures 40 are provided as gas holding structures 41 and 42. The gas holding structure 41 is provided along the port side edge portion 13 a of the ship bottom 13, and the gas holding structure 42 is provided along the starboard side edge portion 13 b of the vessel bottom 13.

  Referring to FIG. 5, the bubbles 70 formed by the air blown out from the air blowing chamber 35 into the water by the air blowing device 30 during navigation form a bubble flow that flows backward so as to cover the ship bottom 13. The bubbles 70 reduce the frictional resistance of the hull 10. The gas holding structures 41 and 42 restrict the movement of the bubbles 70 in the ship width direction Y.

  According to the present embodiment, since the air blowing device 30 blows air from the bow head side 11a having a shallow water depth instead of the deep water bottom 13, the air blowing energy is small. Furthermore, since the gas holding structures 41 and 42 provided on the both sides of the bottom of the ship limit the movement of the air in the ship width direction Y, the air is prevented from deviating from the bottom 13 to the side of the hull 10 due to buoyancy.

(Second Embodiment)
A gas holding structure 40 according to a second embodiment of the present invention will be described with reference to FIG. Since the gas holding structure 40 is a continuous gas holding plate extending in the ship length direction X from the bow side end portion 40a to the stern side end portion 40b, the bow side end portion 40a and the stern side end portion 40b are respectively in front of the gas holding plate. A side edge and a rear edge. In the present embodiment, R is formed on the front edge and the rear edge. By this R, stress concentration in the stress concentration region 80 is reduced. For example, each of the gas holding structures 41 and 42 according to the first embodiment can be formed like the gas holding structure 40 according to this embodiment.

(First Modification of Second Embodiment)
With reference to FIG. 7, a gas holding structure 40 according to a first modification of the second embodiment will be described. In this modification, the front side edge (the bow side end portion 40a) and the rear side edge (the stern side end portion 40b) are inclined. That is, the front edge and the rear edge are formed in a triangle. Due to this inclination, the stress concentration in the stress concentration region 80 is reduced. For example, each of the gas holding structures 41 and 42 according to the first embodiment can be formed like the gas holding structure 40 according to this modification. Note that R may be formed on one of the front edge and the rear edge, and an inclination may be formed on the other of the front edge and the rear edge.

(Third embodiment)
A third embodiment of the present invention will be described with reference to FIG. Except for the following description, the ship according to the third embodiment is the same as the ship according to the first embodiment. In the present embodiment, the plurality of gas holding structures 40 are provided as gas holding structures 41 to 45. The gas holding structures 41 and 42 according to the present embodiment are the same as the gas holding structures 41 and 42 according to the first embodiment. The gas holding structures 43 to 45 are disposed between the gas holding structures 41 and 42. The gas holding structure 43 is provided on the center line CL of the hull 10.

  Each bow side edge part 41a-45a of the gas holding structures 41-45 is arrange | positioned from the stern 12 so that the center line CL is near. Therefore, between the gas holding structure 41 and the gas holding structure 44, between the gas holding structure 44 and the gas holding structure 43, between the gas holding structure 43 and the gas holding structure 45, and between the gas holding structure 45 and the gas holding structure 42. The air blown out by the air blowing device 30 flows into all of the spaces. For example, the bow side end portions 41a to 45a are arranged on a V-shaped line whose apex is located on the center line CL.

  With reference to FIG. 9, in order to help understanding of the effects of the gas holding structures 41 to 45 according to the present embodiment, the effect of holding bubbles during the rolling of the gas holding structures 41 and 42 according to the first embodiment will be described. To do. Since the bubbles 70 can freely move between the gas holding structure 41 and the gas holding structure 42, when the starboard 15 is lifted by rolling, the bubbles 70 gather at one place near the gas holding structure 42 by buoyancy. For this reason, the distribution of the bubbles 70 is uneven, and the frictional resistance reduction effect is reduced.

  With reference to FIG. 10, the effect which hold | maintains the bubble at the time of rolling of the gas holding structures 41-45 which concern on this embodiment is demonstrated. Since the gas holding structures 43 to 45 provided between the gas holding structure 41 and the gas holding structure 42 limit the movement of the bubbles 70 in the ship width direction Y, the bubbles 70 are between the gas holding structure 41 and the gas holding structure 42. Cannot move freely. For this reason, even if the starboard 15 is lifted by rolling, the bubbles 70 do not collect in one place. Accordingly, the distribution of the bubbles 70 cannot be uneven, and the frictional resistance reduction effect does not decrease. The gas holding structures 41 to 45 are preferably arranged at equal intervals in the ship width direction Y.

  The number of gas holding structures provided between the gas holding structures 41 and 42 is not limited to 3, and may be 1 or a plurality other than 3. In addition, each of the gas holding structures 41 to 45 according to the present embodiment is formed like the gas holding structure 40 according to the second embodiment or the gas holding structure 40 according to the first modification of the second embodiment. obtain. In this case, each of the bow side end portions 41a to 45a of the gas holding structures 41 to 45 is a front side edge formed with R or an inclination, and each of the stern side end portions 41b to 45b of the gas holding structures 41 to 45 is provided. Is a rear edge where R or slope is formed.

(Fourth embodiment)
A fourth embodiment of the present invention will be described with reference to FIG. Except for the following description, the ship according to the fourth embodiment is the same as the ship according to the third embodiment. In the ship according to the present embodiment, the propeller inflow prevention structure 60 is provided on the ship bottom 13. Although the case where the gas holding structures 44 and 45 are not provided will be described here, the gas holding structures 44 and 45 may be provided. The propeller inflow prevention structure 60 is disposed on the bow 11 side of the propeller 16. The propeller inflow prevention structure 60 includes an inflow prevention plate 61 protruding downward from the bottom 13 and an inflow prevention plate 62 protruding downward from the bottom 13. The inflow prevention plates 61 and 62 form a V-shape whose interval is widened from the bow 11 side toward the stern 12 side. Since the propeller 16 is located on the center line CL, the bow side end 61a of the inflow prevention plate 61 and the bow side end 62a of the inflow prevention plate 62 are joined on the center line CL to form a V-shaped apex. Form. The vertex of the V shape is joined to the stern side end portion 43 b of the gas holding structure 43.

  According to this embodiment, the propeller inflow prevention structure 60 prevents air from flowing into the propeller 16. Therefore, the efficiency of the propeller 16 is prevented from decreasing due to the inflow air, and the inflow air is prevented from inducing cavitation of the propeller 16 and increasing vibration.

  Note that the V-shaped apex formed by the inflow preventing plates 61 and 62 may not be joined to the stern side end portion 43 b of the gas holding structure 43. The gas holding structure 43 may not be provided. The inflow prevention plates 61 and 62 may form a U shape in which the distance is widened from the bow 11 side toward the stern 12 side, or may form a W shape. Further, the propeller prevention structure 60 may be applied to a ship in which a propeller such as a twin-screw ship is arranged so as to be shifted from the center line.

(Fifth embodiment)
With reference to FIG. 12, a gas holding structure 40 according to a fifth embodiment of the present invention will be described. The gas holding structure 40 includes a plurality of gas holding plates 50 arranged along the ship length direction X from the bow side end portion 40a to the stern side end portion 40b. The plurality of gas holding plates 50 are arranged so that gaps 55 are provided in the ship length direction X. Each gas holding plate 50 includes a front edge 50a and a rear edge 50b. Each of the gas holding structures 41 to 45 can be formed like the gas holding structure 40 according to the present embodiment.

  According to the present embodiment, since the gap 55 of the captain method X is provided in the plurality of gas holding plates 50, even if vertical bending occurs in the hull 10 due to sagging or hogging, the gas holding plate 50 is prevented from being cracked. Is done. As a result, even when the gas holding plate 50 is welded to the ship bottom 13, the hull 10 is prevented from being broken by sagging or hogging.

(First Modification of Fifth Embodiment)
The gas holding structure 40 according to the first modification of the fifth embodiment is the same as the gas holding structure 40 according to the fifth embodiment except for the following description. In the gas holding structure 40 according to the present embodiment, R or an inclination is formed at the front edge 50 a of the gas holding plate 50, and R or an inclination is formed at the rear edge 50 b of the gas holding plate 50. Therefore, stress concentration is reduced. Each of the gas holding structures 41 to 45 can be formed like the gas holding structure 40 according to the present modification.

(Sixth embodiment)
With reference to FIG. 13, the air blowing apparatus 30 which concerns on the 6th Embodiment of this invention is demonstrated. Except for the following description, the air blowing device 30 according to the sixth embodiment is the same as the air blowing device 30 according to the first embodiment. The air blowing device 30 according to the present embodiment includes air blowing chambers 35A and 35B that blow out air into outboard water. The air blowing chambers 35 </ b> A and 35 </ b> B are arranged at a plurality of positions where the water depths on the bow side 11 a are different. The air blowing chamber 35A is disposed at a shallower depth than the air blowing chamber 35B. For example, both the air blowing chambers 35A and 35B are submerged in the full draft state, and only the air blowing chamber 35B is submerged in the ballast draft state. The width L in the ship length direction X of the air blowing chambers 35A and 35B may be larger or smaller than the width H in the water depth direction Z of the air blowing chambers 35A and 35B.

  Referring to FIG. 14, the air blowing device 30 according to the present embodiment includes an air supply device 31 capable of individually supplying air to the air blowing chambers 35A and 35B. The air supply device 31 includes a compressor (or blower or fan) 32, air supply pipes 33A and 33B, and valves 34A and 34B. The air blowing chambers 35A and 35B are connected to the compressor 32 via air supply pipes 33A and 33B, respectively. Valves 34A and 34B are provided in the air supply pipes 33A and 33B, respectively. The air supply device 31 can supply air only to the air blowing chamber 35A, supply air only to the air blowing chamber 35B, and supply air to both the air blowing chambers 35A and 35B.

  According to this embodiment, it is possible to change the air blowing position according to the draft state. Specifically, in the ballast draft state, the air blowing device 30 blows out air only from the air blowing chamber 35B. In the full draft state, the air blowing device 30 blows out air only from the air blowing chamber 35A. By blowing out air only from the air blowing chamber 35A having a shallow water depth, air blowing energy can be reduced. When the ratio of the flow rate of air flowing into the bottom 13 to the flow rate of air blown out by the air blowing device 30 is higher when blowing air from the air blowing chamber 35B than when blowing air from the air blowing chamber 35A. Even in the draft state, the air blowing device 30 may blow out air only from the air blowing chamber 35B. In the full draft state, the air blowing device 30 may blow out air from both the air blowing chambers 35A and 35B.

  The frictional resistance reduction device 20 according to each of the above embodiments is effective not only for fertilized ships but also for lean ships.

  As mentioned above, although this invention was demonstrated with reference to embodiment, this invention is not limited to the said embodiment. Various modifications can be made to the above embodiment, and any combination of the above embodiments is possible.

DESCRIPTION OF SYMBOLS 1 ... Ship bottom part 2 ... Gas chamber 5 ... Gas holding plate 101 ... Hull 102 ... Bow 103 ... Ship bottom 104 ... Stream line 110 ... Air blower 121 ... Bubble 10 ... Ship 11 ... Bow 11a ... Bow ship side 12 ... Stern 13 ... Ship bottom 13a ... Port side edge portion 13b ... Starboard side edge portion 14 ... Port side 15 ... Starboard 16 ... Propeller 20 ... Friction resistance reducing device 30 ... Air blowing device 31 ... Air supply device 32 ... Compressor (blower, fan)
33A, 33B ... Air supply pipes 34A, 34B ... Valves 35, 35A, 35B ... Air blowing chamber 40 (41, 42, 43, 44, 45) ... Gas holding structure 40a (41a-45a) ... Bow end 40b ( 41b to 45b) ... stern side end 50 ... gas holding plate 50a ... front side edge 50b ... rear side edge 55 ... gap 60 ... propeller inflow prevention structures 61 and 62 ... inflow prevention plates 61a and 62a ... bow side end 70 ... Bubble 80 ... Stress concentration region X ... Ship length direction Y ... Ship width direction Z ... Water depth direction L ... Ship length direction width H ... Water depth direction width CL ... Center line

Claims (7)

An air blowing device that blows air into the water from the bow side of the hull;
A plurality of gas holding structures provided so as to protrude downward from the bottom of the hull,
The plurality of gas holding structures are:
A first gas holding structure provided along a port side edge portion of the ship bottom;
Look including a second gas holding structure provided along the starboard side edge portion of the ship bottom,
The plurality of gas holding structures are provided so as to extend in the ship direction,
The plurality of gas holding structures include one or more intermediate gas holding structures disposed between the first gas holding structure and the second gas holding structure,
A plurality of bow side end portions of each of the plurality of gas holding structures are arranged closer to the stern and closer to the center line of the hull and on a V-shaped line whose apex is located on the center line,
A plurality of stern side end portions of each of the plurality of gas holding structures is a ship frictional resistance reduction device arranged on a plane perpendicular to the center line . A propeller inflow prevention structure provided on the bottom of the ship so as to be disposed on the bow side of the propeller;
The ship's frictional resistance reduction device according to claim 1 , wherein the propeller inflow prevention structure protrudes downward from the ship bottom so as to prevent inflow of air into the propeller. Each of the plurality of gas holding structures includes a plurality of gas holding plates arranged along the ship length direction,
Wherein the plurality of gas holding plate, ship frictional resistance reducing device according to claim 1 or 2 arranged so that a gap is provided in the Longitudinal. Each of the plurality of gas holding plates is
A front edge formed with an R or slope;
The ship's frictional resistance reduction device according to claim 3, further comprising a rear edge on which R or an inclination is formed. Each of the plurality of gas holding structures is a gas holding plate extending along the ship length direction,
The gas holding plate is
A front edge formed with an R or slope;
Frictional resistance reduction device for a ship according to claim 1 or 2 and a rear edge R or inclined is formed. The air blowing device is
A plurality of air blowing chambers for blowing air into the outboard water;
An air supply device capable of individually supplying air to the plurality of air blowing chambers,
The ship's frictional resistance reduction device according to any one of claims 1 to 5 , wherein the plurality of air blowing chambers are respectively disposed at a plurality of positions having different water depths on the bow side. Blowing the air into the water from the bow side so that the air wraps around the ship bottom;
A plurality of gas holding structures provided so as to protrude downward from the bottom of the ship, the step of restricting the movement of the air in the width direction of the ship,
The plurality of gas holding structures are:
A first gas holding structure provided along a port side edge portion of the ship bottom;
Look including a second gas holding structure provided along the starboard side edge portion of the ship bottom,
The plurality of gas holding structures are provided so as to extend in the ship direction,
The plurality of gas holding structures include one or more intermediate gas holding structures disposed between the first gas holding structure and the second gas holding structure,
A plurality of bow side end portions of each of the plurality of gas holding structures are arranged closer to the stern and closer to the center line of the hull and on a V-shaped line whose apex is located on the center line,
A method for reducing frictional resistance of a ship in which a plurality of stern side end portions of each of the plurality of gas holding structures are arranged on a plane perpendicular to the center line .

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