Ship hull frictional resistance reducing apparatus

Abstract

This ship hull frictional resistance reducing apparatus: is equipped with an automatic air distribution device 20 which blows off air from a plurality of air blowoff ports to the bottom of a ship by switching between the plurality of air blowoff ports, and automatically distributes the air; and has n-number of the air blowoff ports, each having a prescribed width, disposed at portions obtained by, depending on the breadth of the bottom of the ship, dividing the breadth of the ship hull into n-number of sections. The automatic air distribution device 20 blows off air from all of the plurality of air blowoff ports in one cycle of air blowoff cycle while switching between the plurality of air blowoff ports in a prescribed sequence. With this configuration, cyclical blowoff is utilized, and it is possible to increase a frictional resistance reducing effect due to air lubrication, while suppressing the motive power required for air blowoff.

Description

Hull friction resistance reduction device

[0001] The present invention relates to a ship frictional resistance reduction device that reduces frictional resistance during navigation of a ship by blowing air to form an air bubble flow on the ship's bottom.

[0002] One energy-saving technology for ships is the air lubrication method, which reduces frictional resistance, which accounts for a large proportion of ship resistance, by blowing air from the bottom of the ship and covering the surface of the hull with a flow of air bubbles. For example, Patent Document 1 discloses a hull frictional resistance reduction device that reduces the frictional resistance of a sailing hull by generating air bubbles from a plurality of air jets formed in the bottom of the ship to form an air bubble film on the bottom of the ship, in which the plurality of air jets are aligned in the width direction of the hull to form an air jet group, and a plurality of air jet group groups are formed on the bottom of the ship, and the plurality of air jet group groups include a central air jet group formed in the center in the width direction of the ship and a pair of lateral air jet group groups formed on both sides in the width direction of the central air jet group so as not to overlap with the central air jet group in the width direction, and the central air jet group on the bow side is formed on the bow side of the pair of lateral air jet group groups, and the length in the width direction of the central air jet group is longer than the respective lengths in the width direction of the pair of lateral air jet group groups. Furthermore, Patent Document 2 discloses a hull friction resistance reduction device that includes an air outlet provided on the bottom of the hull, air supply means for supplying air to the air outlet, marine organism adhesion prevention liquid supply means for mixing seawater with a bactericidal liquid to produce a marine organism adhesion prevention liquid and supplying the produced marine organism adhesion prevention liquid to the air outlet, and switching means for selectively connecting either the air supply means or the marine organism adhesion prevention liquid supply means to the air outlet. Patent Document 3 also discloses a hull frictional resistance reduction device comprising: a plurality of air outlets arranged along the width direction on the bottom surface of the hull; air supply means for supplying air to the plurality of air outlets; air supply amount adjustment means for adjusting the amount of air supplied by the air supply means to the plurality of air outlets; water pressure detection and estimation means for detecting or estimating water pressure at the plurality of air outlets; and control means for controlling the air supply amount adjustment means so that the air outlet flow rates at the plurality of air outlets are constant based on the detection and estimation results of the water pressure detection and estimation means, wherein the control means sets the air outlet flow rate at an air outlet located at the center of the hull in the width direction of the hull as a reference air outlet flow rate, and controls the air supply amount adjustment means so that the air outlet flow rates at the other air outlets are the reference air outlet flow rate.

[0003] Patent No. 5022344 Patent No. 5022345 Patent No. 4959668

[0004] In conventional air lubrication methods, air is continuously blown onto the ship's bottom, generating millimeter-sized air bubbles using the shear force of the water current (the blown air is torn apart by the water current). To improve the frictional resistance reduction effect, the amount of blown air must be increased. However, increasing the power required for air blowing reduces the net energy-saving effect (reduced propulsion horsepower due to reduced frictional resistance minus the power required for air blowing). Furthermore, a large-capacity blower or other device is required for air blowing, increasing equipment purchase costs. However, Patent Documents 1 to 3 do not disclose any method for increasing the frictional resistance reduction effect of air lubrication while keeping the power required for air blowing at the same level as conventional methods. In contrast, the present inventors have discovered that periodic blowing (periodic air blowing method), which periodically blows air (periodic air blowing method), achieves a greater frictional resistance reduction effect than continuous blowing, even when the amount of blown air is the same. Figure 8 shows the frictional resistance reduction effect. The data in Figure 8 was obtained by reproducing a flow field equivalent to that of a real ship by towing a 36m long flat plate model at a maximum speed of 8m / s in a 400m water tank at the National Institute of Maritime, Port and Aviation Technology. The test results are shown for each equivalent air film thickness for continuous blowing and for periodic blowing with three air blowing cycles of 0.5Hz, 1.0Hz, and 2.0Hz. ａ is the air blowout flow rate Q and the ship speed V ｍ , the width of the air outlet is B ａ Then, t ａ = Q / (V ｍ ・B ａ ) It can be seen from Figure 8 that the frictional resistance reduction effect is highest when the air blowing frequency is 0.5 Hz. Therefore, an object of the present invention is to provide a ship frictional resistance reduction device that utilizes periodic blowing to increase the frictional resistance reduction effect through air lubrication while suppressing the power required for air blowing.

[0005] A hull frictional resistance reduction device according to claim 1 reduces the frictional resistance of a sailing ship by blowing air supplied from an air supply means through a plurality of air outlets on the bottom of the ship to form an air bubble flow on the bottom of the ship, and is characterized in that the device is equipped with an automatic air distribution device that automatically distributes the air by blowing air from the plurality of air outlets onto the bottom of the ship while switching between the plurality of air outlets, and n air outlets each having a predetermined width are arranged in the width direction of the hull so as to divide the width of the bottom into n parts according to the width of the ship, and the automatic air distribution device blows air from all of the plurality of air outlets in one air blowing cycle while switching between the air outlets that blow out air from among the plurality of air outlets in a predetermined order. According to the present invention described in claim 1, the frictional resistance reduction effect by air lubrication can be increased while suppressing the power required for air blowing from the air supply means. The air blowing flow rate from each air outlet can be determined by determining the air blowing flow rate Q per air outlet when multiple air outlets are blown out simultaneously through design, experiment, simulation, etc.

[0006] The present invention, as set forth in claim 2, is characterized in that the automatic air distribution system has a periodic airflow mode in which air is blown out from multiple air outlets simultaneously, in addition to a periodic airflow mode in which air is blown out from multiple air outlets. In the periodic airflow mode, the airflow rate from each air outlet is set to the same as the airflow rate Q from one air outlet in the continuous airflow mode. According to claim 2, by periodically blowing air at a rate lower than the total airflow rate in continuous airflow, frictional resistance can be reduced to the same extent as in the continuous airflow mode, which uses the total airflow rate. Furthermore, periodic airflow can achieve the same degree of frictional resistance reduction through air lubrication while reducing the power required for air blowing compared to continuous airflow. Note that the term "same" in the phrase "the airflow rate from each air outlet is the same as the airflow rate Q from one air outlet in the continuous airflow mode" may also mean "approximately the same," where "approximately the same" means that the airflow rate from each air outlet is within a range of ±10% of the airflow rate Q in the continuous airflow mode.

[0007] The present invention as set forth in claim 3 is characterized in that the automatic air distribution system includes a control panel and blowers as air supply means, and the control panel sets the control method for the multiple blowers that are distributed. According to the present invention as set forth in claim 3, by distributing multiple air supply means, it is possible to prevent the blowers from becoming larger, eliminating the need to use custom-made products and reducing costs. Furthermore, by controlling multiple air supply means with a single control panel, it is possible to further reduce costs.

[0008] According to a fourth aspect of the present invention, the automatic air distribution system has means for detecting draft information and hull inclination information required to determine the water pressure near the air outlet in order to adjust the air outlet flow rate, and means for detecting ship speed information for optimally controlling the air outlet flow rate according to the ship's speed. According to the fourth aspect of the present invention, the air outlet flow rate can be adjusted accurately.

[0009] According to a fifth aspect of the present invention, in order to distribute the air blown out from the plurality of air outlets on the bottom of the ship evenly across the bottom of the ship, the air outlets are arranged so that the blown air bubble streams overlap in the width direction of the bottom of the ship. According to the fifth aspect of the present invention, the air bubbles can be distributed evenly across the bottom of the ship.

[0010] The present invention as set forth in claim 6 is characterized in that a marine organism adhesion prevention device is provided to prevent clogging of the air outlet due to adhesion of marine organisms, injecting a chemical solution that has the effect of preventing or killing marine organisms into seawater and spraying it out of the air outlet, and when the marine organism adhesion prevention device is in operation, the air supply to the air outlet is cut off and the chemical solution that has the effect of preventing or killing marine organisms is supplied only to the air outlet. According to the present invention as set forth in claim 6, adhesion of marine organisms to the air outlet is effectively suppressed, preventing clogging and maintaining good air outlet conditions.

[0011] According to a seventh aspect of the present invention, the marine organism adhesion prevention device starts operating when the ship is traveling at a low speed before berthing and operates continuously while the ship is berthed. According to the seventh aspect of the present invention, it is possible to more effectively prevent marine organisms from adhering to the air outlet.

[0012] According to the ship frictional resistance reduction device of the present invention, it is possible to increase the frictional resistance reduction effect by air lubrication while suppressing the power required for air blowing from the air supply means.

[0013] Furthermore, the automatic air distribution device has a periodic airflow mode in which air is blown out periodically, as well as a continuous airflow mode in which air is blown out simultaneously from multiple air outlets. In the periodic airflow mode, if the air blowing flow rate from each air outlet is the same as the air blowing flow rate Q from one air outlet in the continuous airflow mode, by performing periodic airflow with the air blowing flow rate from the air outlets reduced below the total flow rate in continuous airflow, it is possible to achieve a reduction in frictional resistance equivalent to that in the continuous airflow mode, which uses the total air blowing flow rate. Furthermore, in periodic airflow, the power required for air blowing can be reduced more than in continuous airflow, while achieving the same degree of frictional resistance reduction effect due to air lubrication.

[0014] Furthermore, the automatic air distribution system includes a control panel and a blower, which is an air supply means. When the control panel sets the control method for multiple blowers that are distributed, distributing multiple air supply means can prevent the blowers from becoming larger, eliminating the need for custom-made products and reducing costs. Furthermore, by controlling multiple air supply means with a single control panel, costs can be further reduced.

[0015] Furthermore, if the automatic air distribution device has a means for detecting draft information and hull inclination information necessary to determine the water pressure near the air outlet in order to adjust the air blowing flow rate, and a means for detecting ship speed information to optimally control the air blowing flow rate according to the ship's speed, the air blowing flow rate can be adjusted accurately.

[0016] In addition, in order to distribute the air blown out from the multiple air outlets on the bottom of the ship evenly across the bottom of the ship, if the air outlets are arranged so that the blown out bubble streams overlap in the width direction of the bottom of the ship, the air bubbles can be distributed evenly across the bottom of the ship.

[0017] In addition, in order to prevent clogging due to the adhesion of marine organisms to the air outlet, a marine organism adhesion prevention device is provided which injects a chemical solution that prevents or kills marine organisms into seawater and blows it out from the air outlet.When the marine organism adhesion prevention device is in operation, the air supply to the air outlet is cut off and the chemical solution that prevents or kills marine organisms from adhering is supplied only to the air outlet, which effectively suppresses the adhesion of marine organisms to the air outlet and prevents clogging, thereby maintaining good air outlet conditions.

[0018] In addition, if the marine organism adhesion prevention device starts operating when the ship is traveling at low speed before anchoring and operates continuously while anchored, it can more effectively prevent marine organisms from adhering to the air outlet.

[0019] FIG. 1 is a diagram showing the configuration of a hull frictional resistance reduction device in a first embodiment of the present invention; FIG. 2 is a diagram showing a first example of the arrangement of the air outlets; FIG. 3 is a diagram showing an example of the arrangement of the air outlets; FIG. 4 is a diagram showing an example of the arrangement of the air outlets; FIG. 5 is a diagram showing an example of the arrangement of the air outlets; FIG. 6 is a diagram showing an example of the arrangement of the air outlets; FIG. 7 is a diagram showing an example of the arrangement of the air outlets; FIG. 1 is a diagram showing the configuration of a hull frictional resistance reduction device in a third embodiment of the present invention; FIG. 1 is a diagram showing the effect of reducing frictional resistance

[0020] A hull frictional resistance reduction device according to a first embodiment of the present invention will now be described. FIG. 1 is a configuration diagram of the hull frictional resistance reduction device according to the first embodiment. In FIG. 1, thin arrows indicate air flow, thick arrows indicate chemical flow, and dotted lines indicate measurement, control, and other signals. The hull frictional resistance reduction device includes multiple air outlets on the bottom of the ship, an automatic air distribution system 20, a marine organism adhesion prevention device 30, and other components. Air is blown out from the air outlets to form an air bubble flow on the bottom of the ship, thereby reducing frictional resistance acting on the ship while it is sailing. The air outlet consists of an air blowing chamber 10 having a predetermined width and multiple air blowing holes 11 provided on the bottom side of the air blowing chamber 10.

[0021] The automatic air distribution system 20 includes an air supply means 21, a device control panel 22 that controls the air supply means 21 and various valves, a ship speed information detection means 23, a draft information detection means 24, a hull inclination information detection means 25, etc. The air supply means 21 supplies air to the air blowing chamber 10. In this embodiment, the air supply means 21 is a blower driven by a motor 21A. Air sent out from the blower flows into the air blowing chamber 10 and is blown out from the air blowing holes 11. The air supply means 21 and the air blowing chamber 10 are connected by a single main pipe 110 and individual pipes 111 branching off from the main pipe 110. The main pipe 110 is provided with an upstream on-off valve 40, a downstream on-off valve 50, and a main flow meter 60. Each individual pipe 111 is connected to one air blowing chamber 10, and each individual pipe 111 is provided with a solenoid valve 70, an individual flow meter 80, a flow rate adjustment valve 90, and a shutoff valve 100. In other words, if the number of air blowing chambers 10 is n, then the numbers of individual pipes 111, solenoid valves 70, individual flow meters 80, flow rate adjustment valves 90, and shutoff valves 100 will also basically be n. The solenoid valve 70 has a normally open mechanism, for example.

[0022] Because the air blowing holes 11 are in contact with seawater, they may become clogged due to the adhesion of marine organisms such as shellfish. The marine organism adhesion prevention device 30 supplies a chemical solution to the air blowing holes 11 to suppress the adhesion of marine organisms and prevent the air blowing holes 11 from being clogged. The marine organism adhesion prevention device 30 in this embodiment is a chemical solution injection type that injects a chemical solution that prevents or kills marine organisms into seawater. Each air blowing chamber 10 and the marine organism adhesion prevention device 30 are connected via piping that has a check valve 120 installed in the middle, and the chemical solution supplied from the marine organism adhesion prevention device 30 to the air blowing chamber 10 is blown out from the air blowing holes 11. When the marine organism adhesion prevention device 30 is in operation, the air supply to the air blowing chamber 10 is shut off by the shutoff valve 100, and the chemical solution that has the effect of killing marine organisms is supplied only to the air blowing chamber 10. This effectively suppresses adhesion of marine organisms to the air blowing holes 11, preventing blockage and maintaining a good blowing state of the air blowing holes 11. The marine organism adhesion prevention device 30 preferably starts operation when the ship is traveling at a low speed before anchoring and operates continuously while the ship is at anchor. Since the likelihood of marine organisms attaching to the air blowing holes 11 increases not only when the ship is at anchor but also when traveling at a low speed, the supply of chemical solution to the air blowing chamber 10 can be started before anchoring and the chemical solution can be supplied to the air blowing chamber 10 continuously or periodically while the ship is at anchor, thereby more effectively suppressing adhesion of marine organisms to the air blowing holes 11. Note that a separate mixing promotion means may be provided so that the chemical solution is sufficiently mixed with seawater by injection before being supplied to the air blowing chamber 10.

[0023] 2-1 to 2-3 show examples of air outlet arrangements, with FIG. 2-1 showing a first arrangement example, FIG. 2-2 showing a second arrangement example, and FIG. 2-3 showing a third arrangement example. Multiple air blowing chambers 10 are provided on the bow side. Each air blowing chamber 10 is arranged in each of n sections that are virtually divided across the width of the ship's bottom, where n is the number of air blowing chambers 10. In the first to third arrangement examples, multiple air blowing chambers (air blowing sections) 10 are arranged approximately perpendicular to the center line α of the hull 1, with the same number of air blowing chambers on both the port and starboard sides. The n sections may be equally or unequally divided, and even if the sections are equally divided, the air blowing chambers 10 may be arranged at intervals from the center within each section.

[0024] In the first arrangement example shown in Figure 2-1, the first air blowing chamber 10a and the fourth air blowing chamber 10d are arranged closer to the sides of the hull, and the second air blowing chamber 10b and the third air blowing chamber 10c are arranged closer to the center of the hull. The longitudinal position of the second air blowing chamber 10b is the same as the longitudinal position of the third air blowing chamber 10c, and the longitudinal position of the first air blowing chamber 10a is the same as the longitudinal position of the fourth air blowing chamber 10d. The second air blowing chamber 10b and the third air blowing chamber 10c are located further forward than the first air blowing chamber 10a and the fourth air blowing chamber 10d. The lengths of the air blowing chambers 10 are approximately the same.

[0025] 2-2 is similar to the first embodiment, except that the distance in the longitudinal direction between the second air blowing chamber 10b and the third air blowing chamber 10c, which are located closer to the center of the hull, and the first air blowing chamber 10a and the fourth air blowing chamber 10d, which are located closer to the sides of the hull, is wider than in the first arrangement example, and that all of the air blowing chambers 10 are located inside the flat line β of the bottom of the hull, i.e., on the flat part of the bottom of the hull. By locating all of the air blowing chambers 10 inside the flat line β of the bottom of the hull, it becomes easier for a bubble flow to form on the flat part of the bottom of the hull.

[0026] 2-3, the fifth air blowing chamber 10e and the sixth air blowing chamber 10f are arranged closer to the center of the hull, and the seventh air blowing chamber 10g, the eighth air blowing chamber 10h, the ninth air blowing chamber 10i, the tenth air blowing chamber 10j, the eleventh air blowing chamber 10k, and the twelfth air blowing chamber 10m are arranged along the ship bottom flat line β, with all of the air blowing chambers 10 being located inside the ship bottom flat line β. The positions in the ship length direction are the same for the fifth air blowing chamber 10e and the sixth air blowing chamber 10f, the seventh air blowing chamber 10g and the eighth air blowing chamber 10h, the ninth air blowing chamber 10i and the tenth air blowing chamber 10j, and the eleventh air blowing chamber 10k and the twelfth air blowing chamber 10m. The fifth air blowing chamber 10e and the sixth air blowing chamber 10f are located at the front, followed by the seventh air blowing chamber 10g and the eighth air blowing chamber 10h, then the ninth air blowing chamber 10i and the tenth air blowing chamber 10j, and then the eleventh air blowing chamber 10k and the twelfth air blowing chamber 10m. The fifth to tenth air blowing chambers 10e to 10j are all approximately the same length, and the eleventh air blowing chamber 10k and the twelfth air blowing chamber 10m are also approximately the same length. The eleventh air blowing chamber 10k and the twelfth air blowing chamber 10m are longer than the fifth to tenth air blowing chambers 10e to 10j.

[0027] To distribute the air blown from the multiple air blowing chambers 10 evenly across the ship's bottom, it is preferable to arrange the air blowing chambers 10 so that the blown air bubble streams overlap in the width direction of the ship's bottom. For example, in the first and second arrangement examples, the first air blowing chamber 10a and the second air blowing chamber 10b, and the third air blowing chamber 10c and the fourth air blowing chamber 10d overlap in the width direction of the ship's bottom. That is, assuming that the air blowing chambers 10 are positioned in the same longitudinal direction, the first air blowing chamber 10a and the second air blowing chamber 10b partially overlap, and the third air blowing chamber 10c and the fourth air blowing chamber 10d partially overlap. Furthermore, in the third arrangement example, the ninth air blowing chamber 10i and the eleventh air blowing chamber 10k, and the tenth air blowing chamber 10j and the twelfth air blowing chamber 10m overlap in the width direction of the ship's bottom. In this way, by arranging the air blowing chambers 10 so that they overlap in the width direction of the ship's bottom, air bubbles can be distributed uniformly over the ship's bottom.

[0028] The automatic air distribution device 20 has two modes for air blowing. One mode is a continuous blowing mode in which air is blown out simultaneously from multiple air blowing chambers 10. The other mode is a cyclic blowing mode in which air is blown out by switching between the air blowing chambers 10. In the continuous blowing mode, the solenoid valve 70 is de-energized so that air is blown out simultaneously and continuously from all of the air blowing chambers 10. On the other hand, in the cyclic blowing mode, air is blown out from each air blowing chamber 10 in a predetermined order by controlling the opening and closing of the solenoid valve 70.

[0029] FIG. 3 shows air blowing patterns in the periodic blowing mode, with FIG. 3(a) showing the first pattern and FIG. 3(b) showing the second pattern. In the first pattern, blowing is switched in sequence from the air blowing chamber 10 located on either the left or right side to the adjacent air blowing chamber 10. For example, in the case of four air blowing chambers 10 as in the first and second arrangement examples, one cycle is "blowout from only the first air blowing chamber 10a → blowout from only the second air blowing chamber 10b → blowout from only the third air blowing chamber 10c → blowout from only the fourth air blowing chamber 10d," and this cycle is repeated. In the second pattern, blowing is switched in sequence from the air blowing chamber 10 located on the side to the air blowing chamber 10 located in the center. For example, in the case of four air blowing chambers 10, as in the first and second arrangement examples, one cycle is "blowout by only the first air blowing chamber 10a → blowout by only the fourth air blowing chamber 10d → blowout by only the second air blowing chamber 10b → blowout by only the third air blowing chamber 10c," and this cycle is repeated. In either pattern, air blowing chambers 10 other than those on duty suspend blowing until their next turn. While it is preferable that the air blowing flow rate from the suspending air blowing chamber 10 be zero, it is acceptable for some leaked air (within approximately 10% of the specified air blowing flow rate) to be blown out due to air leakage from the shutoff valve 100. Furthermore, it is desirable for the air blowing flow rate from the air blowing chamber 10 on duty to be Q, but it is acceptable for the air blowing flow rate to be less than Q due to air leakage. In this way, the automatic air distribution device 20 automatically distributes air by switching between the multiple air blowing chambers 10 to blow air from the multiple air blowing holes 11 to the bottom of the ship from all of the multiple air blowing chambers 10 in one air blowing cycle. The air blowing pattern is set appropriately based on the number of air blowing chambers 10, the shape and size of the hull 1, etc.

[0030] In the periodic blowing mode, the air blowing flow rate from each air blowing chamber 10 in one cycle is set to be the same (approximately the same) as the air blowing flow rate Q in the continuous blowing mode. By periodically blowing the air blowing flow rate from the air blowing chamber 10 at a rate lower than the total flow rate in continuous blowing, frictional resistance reduction equivalent to that achieved in the continuous blowing mode, which uses the total air blowing flow rate, can be achieved. Furthermore, periodic blowing can achieve the same degree of frictional resistance reduction effect through air lubrication while reducing the power required for air blowing compared to continuous blowing. Note that "approximately the same" refers to allowing a difference of up to ±10% in the air blowing flow rate Q, as described above, taking into account factors such as pulsation of the air supply means 21, variations in resistance in the individual pipes 111 branching from the main pipe 110, and variations in resistance in the solenoid valve 70. In the periodic blowing mode, the air blowing cycle is preferably set to 0.5 Hz (1 cycle: 2 seconds) and the duty ratio to 0.25. The duty ratio indicates the proportion of time during one cycle during which air is blown out. A duty ratio of 0.25 results in 25% air blowing time and 75% pause time. In other words, one cycle of "0.5-second air blowing followed by a 1.5-second pause" is repeated in one air blowing chamber 10. This achieves a high frictional resistance reduction effect. Furthermore, in the continuous blowing mode, the air blown out from each air blowing chamber 10 is reduced and continuous blowing is performed, thereby achieving the same frictional resistance reduction as in the conventional continuous blowing mode with the air blowing flow rate Q. When the steady inclination (vertical inclination (trim) or horizontal inclination (heel)) of the hull 1 or the hull motion (pitching (pitch) or horizontal rolling (roll)) is large, or when the ship speed is slow (e.g., 5 m / s or less), the expected resistance reduction effect cannot be achieved by the periodic blowing mode, and the continuous blowing mode may provide a greater frictional resistance reduction effect. In such cases, the continuous blowing mode is switched to. Here, the automatic air distribution device 20 further improves the effect of reducing friction resistance by adjusting the equivalent air film thickness t ａ It is preferable to adjust the air blowing flow rate Q so that the equivalent air film thickness t ａ As mentioned above, Q / (V ｍ ・B ａ )

[0031] The automatic air distribution device 20 adjusts the air blowing flow rate based on the calculated water pressure near the air blowing holes 11, and optimally controls the air blowing flow rate based on the ship's speed. This allows the air blowing flow rate to be accurately adjusted according to the water pressure and ship speed. Draft information and hull inclination information required to calculate the water pressure near the air blowing holes 11 are transmitted from the draft information detection means 24 and the hull inclination information detection means 25 to the device control panel 22, and ship speed information required to determine the ship's speed is transmitted from the ship speed information detection means 23 to the device control panel 22.

[0032] Next, a hull frictional resistance reduction device according to a second embodiment of the present invention will be described. Note that functional components identical to those in the above-described embodiment are designated by the same reference numerals and will not be described again. FIG. 4 is a configuration diagram of a hull frictional resistance reduction device according to the second embodiment. This hull frictional resistance reduction device differs from the first embodiment in that it includes multiple automatic air allocation devices 20 and multiple sets of air blowing chambers 10. As shown in FIG. 4, there are N automatic air allocation devices 20, numbered "automatic air allocation device-1" through "automatic air allocation device-N." Of these, only "automatic air allocation device-1" is equipped with a device control panel 22. Automatic air allocation devices 2 to 1, which do not have device control panels 22, are controlled by the device control panel 22 installed in "automatic air allocation device-1." In other words, the single device control panel 22 installed in "automatic air allocation device-1" is responsible for controlling all of the automatic air allocation devices 20, from "automatic air allocation device-1" through "automatic air allocation device-N." After air is blown out, the frictional resistance reduction effect decreases at a position a certain distance downstream from the air blowing holes 11 (e.g., 50 m or more downstream). Therefore, for ships with a long length, it is preferable to install multiple chamber sets consisting of multiple air blowing chambers 10 in the longitudinal direction. This allows a high frictional resistance reduction effect to be maintained over a wide area of ​​the bottom of the ship, even on large ships. However, installing multiple chamber sets increases the required blowing air volume, which results in larger blowers and custom-made products, resulting in higher costs. Therefore, in this embodiment, an air supply means 21 is provided for each automatic air distribution unit 20, and one air supply means 21 is used for each chamber set. In this way, by providing multiple automatic air distribution units 20 and distributing multiple air supply means 21 in a distributed manner, the blower size (air blowing volume per unit time) can be prevented from increasing, eliminating the need for custom-made products and reducing costs. In addition, each automatic air distribution device 20 is equipped with one blower, which is an air supply means 21, but as mentioned above, one automatic air distribution device 20 has a representative device control panel 22, and this single device control panel 22 is used to set the control method for the multiple blowers that are distributed.In this way, costs can be reduced by controlling multiple blowers with a single device control panel 22. Also, only one marine organism adhesion prevention device 30 is installed and shared by each chamber group. Therefore, the chemical solution is supplied to all air blowing chambers 10 from the same marine organism adhesion prevention device 30.

[0033] Figures 5-1 to 5-4 show examples of air outlet arrangements, with Figure 5-1 being a fourth arrangement example, Figure 5-2 being a fifth arrangement example, Figure 5-3 being a sixth arrangement example, and Figure 5-4 being a seventh arrangement example. In the fourth arrangement example shown in Figure 5-1, three sets of chambers are arranged spaced apart in the longitudinal direction of the ship, each set consisting of a first air outlet chamber 10a, a second air outlet chamber 10b, a third air outlet chamber 10c, and a fourth air outlet chamber 10d. The arrangement of the air outlet chambers 10 in each set is the same as in the first arrangement example. The first automatic air allocation device 20 is applied to the chamber set located first from the front, the second automatic air allocation device 20 is applied to the chamber set located second from the front, and the third automatic air allocation device 20 is applied to the chamber set located third from the front.

[0034] In the fifth arrangement example shown in Figure 5-2, two chamber sets, each consisting of one first air blowing chamber 10a, one second air blowing chamber 10b, one third air blowing chamber 10c, and one fourth air blowing chamber 10d, are arranged spaced apart in the longitudinal direction of the ship. The arrangement of the air blowing chambers 10 in each set is the same as in the second arrangement example. All of the air blowing chambers 10 are arranged on the flat part of the bottom of the ship. The first chamber set located from the front is equipped with a first automatic air distribution device 20, and the second chamber set located from the front is equipped with a second automatic air distribution device 20.

[0035] In the sixth arrangement example shown in Figure 5-3, a first air blowing chamber 10a, a second air blowing chamber 10b, a third air blowing chamber 10c, and a fourth air blowing chamber 10d are arranged as a group, and a fifth air blowing chamber 10e, a sixth air blowing chamber 10f, a seventh air blowing chamber 10g, an eighth air blowing chamber 10h, a ninth air blowing chamber 10i, a tenth air blowing chamber 10j, an eleventh air blowing chamber 10k, and a twelfth air blowing chamber 10m are arranged as a group, with the former being arranged further aft than the latter. In the former chamber group, the second air blowing chamber 10b and the third air blowing chamber 10c, which are located closer to the center of the hull, are positioned in the longitudinal direction of the ship, and the first air blowing chamber 10a and the fourth air blowing chamber 10d, which are located closer to the side of the hull, are positioned in the same longitudinal direction. The arrangement of the air blowing chambers 10 in the latter chamber group is the same as in the third arrangement example. All of the air blowing chambers 10 are arranged on the flat bottom of the ship. The first set of chambers from the front is fitted with a first automatic air distribution device 20, and the second set of chambers from the front is fitted with a second automatic air distribution device 20.

[0036] The seventh arrangement example shown in Figure 5-4 is similar to the sixth arrangement example, except that in a chamber group consisting of a first air blowing chamber 10a, a second air blowing chamber 10b, a third air blowing chamber 10c, and a fourth air blowing chamber 10d, the second air blowing chamber 10b and the third air blowing chamber 10c, which are provided closer to the center of the hull, are positioned forward of the first air blowing chamber 10a and the fourth air blowing chamber 10d, which are located closer to the side of the hull. Note that in the fourth to seventh arrangement examples shown in Figures 5-1 to 5-4, multiple chamber groups are arranged spaced apart in the longitudinal direction of the ship, and the blown air is controlled by multiple automatic air distribution devices 20, but multiple chamber groups can also be arranged and controlled as groups separated on the left and right of the center line α of the hull 1.

[0037] Next, a hull frictional resistance reduction device according to a third embodiment of the present invention will be described. Note that the same functional components as those in the above-described embodiments are assigned the same reference numerals, and description thereof will be omitted. Figure 6 is a configuration diagram of the hull frictional resistance reduction device according to the third embodiment. The hull frictional resistance reduction device according to this embodiment differs from the second embodiment in that it has a plurality of marine organism adhesion prevention devices 30, with one marine organism adhesion prevention device 30 installed for each chamber set. By distributing the marine organism adhesion prevention devices 30, it is possible to prevent the marine organism adhesion prevention devices 30 from becoming larger and reduce costs.

[0038] Next, a hull frictional resistance reduction device according to a fourth embodiment of the present invention will be described. Note that functional components identical to those in the above-described embodiments are designated by the same reference numerals and will not be described again. FIG. 7 is a structural diagram of the hull frictional resistance reduction device according to the fourth embodiment. This embodiment differs from the first embodiment in that it includes an inverter panel 21B between the device control panel 22 and the air supply means 21 and a buffer tank 130 downstream of the air supply means 21. While omitting the inverter panel 21B as in the first embodiment can reduce costs, providing the inverter panel 21B as in the present embodiment enables smoother control of the blower. Furthermore, by increasing the diameter of the piping downstream of the air supply means 21 by a predetermined amount, the buffer tank 130 as in the first embodiment can be eliminated. However, in cases where the diameter of the piping cannot be increased by a predetermined amount, providing the buffer tank 130 as in the present embodiment can suppress air pulsation and ensure stable supply to the air blowing chamber 10.

[0039] As described above, the ship frictional resistance reduction device of the present invention utilizes periodic air blowing to increase the frictional resistance reduction effect through air lubrication while keeping the power required for air blowing at the same level as in the past.

[0040] In addition to the configuration of the above-described embodiment, the air blowing outlet can also be configured to include, for example, an air blowing chamber 10, an air distribution plate that homogenizes the air flow in the air blowing chamber 10, and air blowing holes 11, or the air blowing holes 11 can be provided directly or directly connected to individual pipes 111.

[0041] The present invention can configure a system not only for small and medium-sized ships, but also for large ships without using custom-made blowers, inverters, etc., making it possible to configure a cost-effective air lubrication system while reducing the power required for air blowing.

[0042] REFERENCE SIGNS LIST 10 Air blowing chamber 11 Air blowing hole 20 Automatic air distribution device 21 Air supply means (blower) 22 Device control panel 23 Ship speed information detection means 24 Draft information detection means 25 Hull inclination information detection means 30 Marine organism adhesion prevention device

Claims

1. A hull friction resistance reduction device that reduces the frictional resistance of a sailing ship by blowing air supplied from an air supply means out of multiple air outlets on the bottom of the ship to form an air bubble flow on the bottom of the ship in order to reduce frictional resistance acting on the ship, the device comprising an automatic air distribution device that causes air to be blown out from the multiple air outlets onto the bottom of the ship while switching between the multiple air outlets and automatically distributes the air, and n air outlets each having a predetermined width are arranged in n divisions across the width of the bottom of the ship, and the automatic air distribution device blows out the air from all of the multiple air outlets in one air blowing cycle while switching between the air outlets that blow out the air from among the multiple air outlets in a predetermined order.

2. The automatic air distribution device has a periodic blowing mode in which the air is blown out periodically, as well as a continuous blowing mode in which the air is blown out simultaneously from a plurality of the air outlets, and in the periodic blowing mode, the air blowing flow rate from each of the air outlets is set to be the same as the air blowing flow rate Q from one of the air outlets in the continuous blowing mode.

3. A hull friction resistance reduction device as described in claim 1 or 2, characterized in that the automatic air distribution device includes a device control panel and a blower which is the air supply means, and the device control panel sets the control method for the multiple blowers which are distributed.

4. A hull friction resistance reduction device as described in claim 2 or 3, characterized in that the automatic air distribution device has a means for detecting draft information and hull inclination information necessary to determine the water pressure near the air outlet in order to adjust the air blowing flow rate, and a means for detecting ship speed information to optimally control the air blowing flow rate according to the ship's navigation speed.

5. A hull friction resistance reduction device as described in any one of claims 1 to 4, characterized in that the air outlets are arranged so that the air bubble flows blown out from the multiple air outlets on the bottom of the ship overlap in the width direction of the bottom of the ship, in order to distribute the air blown out from the multiple air outlets on the bottom of the ship evenly across the bottom of the ship.

6. A hull friction resistance reduction device as described in any one of claims 1 to 5, characterized in that it is equipped with a marine organism adhesion prevention device that injects a chemical solution that has the effect of preventing or killing marine organisms from adhering to the air outlet and sprays it out of the air outlet in order to prevent clogging due to the adhesion of marine organisms, and when the marine organism adhesion prevention device is operating, it cuts off the air supply to the air outlet and supplies the chemical solution that has the effect of preventing or killing marine organisms from adhering only to the air outlet.

7. A ship friction resistance reduction device as described in claim 6, characterized in that the marine organism adhesion prevention device starts operating when the ship is traveling at a low speed before berthing and operates continuously while the ship is berthing.

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