KR20110128824A - Method for generating air bubbles in an apparatus for reducing friction resistance in a ship - Google Patents

Abstract

The present invention develops and provides a method for generating low pressure microbubbles in a frictional resistance reduction apparatus in a ship which can generate bubbles by the pressure of natural water flow to obtain more effective friction reduction reduction. In the frictional resistance reduction apparatus of a ship, the intake port 1 installed in the position below the waterline Y near the bow X, and the jet port provided in the ship bottom (bottom of the ship) Z near the bow X. The low pressure microbubble is generated by using a decompression phenomenon in the middle with (2), and if necessary, it is sent without pressurizing to the bottom of an arbitrary depth, and also in the ejection opening 2 without being influenced by the surrounding hydraulic environment. It is a method that makes it possible to obtain the effect of reducing frictional resistance by ejecting the ship, and it is simpler and more cost effective than the conventional device, and the cost of manufacturing and installation, the energy consumption cost for air pressurization, and the generated air bubbles are required for the hull. It is to reduce the energy consumption cost required in the process of distributing the parts.

Description

Bubble generation method of frictional resistance reduction device of ship {METHOD FOR GENERATING AIR BUBBLES IN AN APPARATUS FOR REDUCING FRICTION RESISTANCE IN A SHIP}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of generating bubbles in a frictional resistance reduction device of a large ship such as a tanker. In particular, a low pressure microbubble is mainly used to reduce frictional resistance generated between the hull receiving surface and water during large vessel operation. It relates to a method of generating bubbles generated by the pressure of).

Conventionally, the bubble generator which reduces the frictional resistance which generate | occur | produces between the receiving surface of a ship body and water at the time of ship operation focused on the point that a bubble is minute and it is easy to generate | occur | produce in a high hydraulic pressure environment.

For example, in order to reduce the resistance of water at the time of ship operation, various methods of interposing air bubbles or air layers on the hull wall surface are disclosed. For example, at the speed of blowing the compressed air blown from the ship side at a slower speed than the ship speed, the air bubbles are blown obliquely backwards of the hull while the air bubbles generated at the ship side are smaller than the micro bubbles generated at the ship bottom (bottom). A method of making a diameter and sending it into the boundary layer is disclosed. For example, patent document 1 and patent document 2 are the same.

However, it is difficult to obtain fine bubbles in this manner, and in reality, the energy consumption due to blowing the bubbles is large and it is not practical. Therefore, the technique can be easily performed by reducing the frictional resistance with low energy consumption, and allowing the bubble mixing fluid to be ejected obliquely backward in the boundary layer so that the bubble mixing rate can be easily adjusted and effective friction reduction can be achieved. Is disclosed. For example, it is the same as that of patent document 3.

Moreover, the technique which aims at the frictional resistance reduction effect of a ship by generating a micro bubble using the pressure reduction with respect to atmospheric pressure is disclosed. For example, it is the same as patent document 4, patent document 5, and patent document 6.

According to this method, since it is possible to generate low pressure microbubbles without pressurizing air, there are two advantages over the conventional pressurization method. One is that the low pressure microbubbles generated have very little expandable properties, resulting in more efficient frictional low pressure effects. The other is that it is possible to generate bubbles with less energy consumption by not using an air pressurization device, such as a compressor, it is possible to reduce the cost accordingly. However, the following problem can also be pointed out in the method of generating low pressure microbubbles by using the above-mentioned pressure reduction.

That is, in the low pressure microbubble generating device, the generation process of the low pressure microbubble does not generate bubbles in the hydraulic environment higher than any constant hydraulic environment because it is inhibited by the influence of the surrounding hydraulic pressure.

In particular, in the case of a large ship such as a tanker with a bottom level of 10 to 20 m, the effect of reducing frictional resistance is expected to be generated by using a device such as a compressor as in the pressurization method. This advantage disappears.

Japan Patent Publication No. 2008-18781 Japanese Patent Laid-Open No. 11-227674 Japanese Patent Laid-Open No. 07-156859 Japanese Patent Laid-Open No. 2002-79986 Japanese Patent Laid-Open No. 2002-68073 Japanese Patent Laid-Open No. 2002-79985

Accordingly, the present invention seeks to solve these problems.

The 1st problem is not providing the apparatus which produces the high pressure valve which has a negative property with respect to the above-mentioned frictional resistance reduction effect, but is non-expandable which does not have the property which expands greatly even after being ejected by boat. The present invention provides and develops a method for generating low pressure microbubbles in a frictional resistance reduction apparatus of a ship that can generate bubbles by the pressure of natural water to obtain more effective frictional resistance reduction.

The second problem is that in the process of generating low pressure micro bubbles using a conventional pressure reduction phenomenon, bubbles are inhibited due to the influence of water pressure in the process of generating low pressure micro bubbles, or an air pressurization device such as a compressor is used under a constant pressure environment. It is not necessary to provide a method that needs to generate microbubbles. Instead, a low pressure microbubble is generated by removing the influence of water pressure that inhibits bubble generation in the process of generating low pressure microbubbles by using a pressure reduction phenomenon. Therefore, the development and provision of a method that makes it possible not to pressurize to the bottom of the ship (bottom of the ship) without pressure or to discharge the ship from the jet port by the ship without being influenced by the surrounding hydraulic environment. will be.

The third problem is to develop and provide a simpler and more cost-effective structure for the microbubble generating device and the complicated structure of the water supply path in the frictional resistance reduction device of the conventional ship, and to manufacture and install the cost and also pressurize the air. It is to reduce the energy consumption cost required in the process, and the energy consumption cost required in the process of distributing the generated bubbles to the required portion of the hull.

As a means for solving the problem according to the present invention, the means for solving the first problem is a low pressure microbubble generating device in the low pressure microbubble generating method. As shown in the figure, the device is composed of two bubble generating areas forming a depressurized zone with respect to atmospheric pressure. The depressurized zone generated at this site is used to naturally suck air in the water stream, and thus to have a low pressure having non-expandable properties. It is characterized by generating microbubbles.

The means for solving the above second problem is due to the positional configuration of the water supply path from the intake port to the outlet port itself.

The means for solving the third problem is also due to the positional configuration itself of the water supply path from the intake port to the outlet port.

According to the present invention has the following effects.

1) It is possible to generate a large amount of low pressure micro bubbles which are more effective in reducing the frictional resistance of a ship without depending on air pressurization. The air sucked into the water in the reduced pressure region formed at the low pressure microbubble generation area is not pressurized at all and is kept at a low pressure state, and instantly becomes a microbubble and is ejected to the necessary part with water flow as it is. This low pressure microbubble that is not pressurized maintains non-expansion even when released into water as compared with the high pressure bubble generated by a conventional air pressurizing device, and maintains a size of about 0.1 to 0.2 mm in diameter, thereby providing more effective frictional resistance reduction effect. Gives birth

2) It is possible to generate a large amount of low pressure micro bubbles without being affected by the hydraulic environment. At the same time it is also possible to generate it at a jet of any depth in the ship. As a device for generating low pressure micro bubbles by using a conventional pressure reduction phenomenon, since a low pressure micro bubble is not located at the bottom of the ship bottom, even when used in a large vessel, a high pressure bubble having a water resistance property is used by using an air pressure device such as a compressor. There is no need to create it.

3) Cost-effectiveness is high in bubble generation and off-board distribution. The position structure of the water supply path of the present invention makes it possible to use the natural water flowing in at the time of navigation as it is as a power source of the water flow, and hardly uses the power to pressurize the water flow. In addition, since the power required for the bubble generation process uses the same water flow, no air pressurization device is required. It is possible to make an effect with less energy consumption.

4) The method of generating low pressure micro bubbles is very simple. That is, the technology required for fabrication does not need to be special, and the cost is lower than that of the conventionally known bubble generator, and the cost for maintenance is also low.

1 is a partial nodule side view showing an example of an apparatus used in the practice of the present invention;
2 is a partially enlarged explanatory diagram showing an example of an apparatus used in the practice of the present invention;
3 is a front view showing an example of an apparatus used in the practice of the present invention;
Figure 4 shows an example of the primary bubble generating site and the primary bubble generating site of the experimental apparatus for verifying the practice of the present invention, (a) is a partially cutaway perspective view, (b) is a partially cutout front view. .
5 shows another example of the primary bubble generating site and the primary bubble generating site of the experimental apparatus for verifying the practice of the present invention, (a) is a partially cutaway perspective view, and (b) is a partially cutaway front view. to be.
6 is a partially cutaway explanatory diagram showing an example of an experimental apparatus for verifying the practice of the present invention;
7 is a partially cutaway explanatory diagram showing an example of an experimental apparatus for verifying the practice of the present invention;
8 is a graph showing data of an experimental apparatus for verifying the practice of the present invention;
9 is an explanatory diagram of a measuring device for measuring data of an experimental apparatus for verifying the practice of the present invention.

The present invention provides a water supply path for generating a low pressure microbubble in the ship's hull, a water inlet is provided at the bottom of the ship (bottom part) under the draft line near the ship's head, The low pressure microbubbles are generated at a position above the waterline in the middle of the. The low pressure microbubbles are generated in two places, and the primary bubble generating part has a first air inlet pipe formed inside the water pipe forming a water path, and a cross section is narrowed by two pipes of the water pipe and the air inlet pipe. The secondary bubble generating portion is connected to form a narrow gap between the air inlet pipe and the water pipe by cross-sectioning the water supply pipe inside the second air inlet pipe which similarly forms the water supply path. have.

The present invention draws air from the air inlet pipe by using a depressurization zone generated at a narrow gap in each bubble generating area and suction-mixes it in the water flow flowing through the water supply path. It is a device for generating micro bubbles, and the water pump is mainly used to supply water flow from the intake port below the water line to the position of the bubble generation site above the water line at the start of the navigation, or to use it as a power source of the water auxiliary at low speed navigation. It is installed.

[Example]

An embodiment of the present invention will be described in detail with reference to the drawings. In the apparatus for reducing frictional resistance of a ship, a water intake port 1 provided at a position below the waterline Y in the vicinity of the bow X, and the bow X The outlet port 2 installed at the bottom of the ship (Z) close to) is connected to a continuous single pipe consisting of water pipes 3a and 3a 'and a mixed water pipe 3b. The water supply pump 4 is mounted in the water supply pipe 3a at the same level as the water intake port 1 at the rear of the water intake port 1, and the water supply pipe 3a 'at the rear thereof is located above the waterline Y. When both pipes overlap inside and outside than the water pipe 3a 'at the stern side of the water pipe 3a' which is piped in the stern direction so that the first air inlet pipe 5a of a thin thickness having a narrow gap is formed. Bend the tip in the direction of water flow to penetrate the water pipe 3a, and insert the first hole at the position where both pipes are parallel. When the inlet pipe 5a is cut at its tip and the surrounding area or the position near the position is the primary bubble generating site A, then an adjustment valve 6 is mounted on the rear side thereof, and in the case of overlapping with the water supply pipe in and out. The water pipe 3a 'is mounted so as to surround the water pipe 3a' from the outside with the second air inflow pipe 5b having a thickness of about one interval, and the water pipe 3a 'is cut at a position where both pipes are parallel to each other. The area or the position near the position is the secondary bubble generating portion (B), and the second air inlet pipe (5b) is a radix mixed water supply pipe for sending the air-water mixed water stream in its extended form after that position ( 3b) is connected to the outlet port 2, and the inflow water from the intake port 1 is discharged using the pressure reduction phenomenon against the atmospheric pressure generated in the primary bubble generation site (A) and the secondary bubble generation site (B). 1, air is sucked from the air inlet pipe 5a and the second air inlet pipe 5b, and the low pressure micro To generate air at the jet resistance port 2 without using any power together with the air-water mixed water stream ejected from the radix mixed water pipe 3b. do.

The control valve mounted on the second air inlet pipe 5b is an air inlet increase control valve functionally.

Next, when each structure and function of the apparatus used for the frictional resistance reduction method of the ship of this invention are explained in full detail,

1) Water intake

Since the size of the intake port 1 is preferably large intake within a range that does not interfere with the function of the hull, the larger the intake port 1 is. In addition, it is necessary to provide a filter so as not to be clogged with garbage or the like at the first bubble generating portion (A) and the second bubble generating portion (B).

2) Water Pump

Most of the intake is to use the natural water flow according to the progress of the ship, but it is necessary to intake with the water feed pump 4 when the ship proceeds for the first time or when traveling at low speed.

3) Low pressure micro bubble generator

As a device for generating as many micro bubbles as one of the main objectives of the present invention, as shown in Figs. 1 and 2, the primary bubble generating portion (A) and the secondary bubble generating portion (B) are provided. The primary bubble generating portion (A) is inserted through the first air inlet pipe (7a) into the water pipe (3 '), cut into appropriate lengths, the water pipe (3a') and the first air inlet pipe ( The air is sucked out of the first air inlet pipe 7a by using a powerful depressurization zone generated near the cut surface of the first air inlet pipe 7a due to the water flow ejected from the narrow gap of 7a), and at the same time, the low pressure minute Bubbles are generated, mixed with the water flow, and sent to the secondary bubble generating site (B). The second bubble generating portion B cuts the water supply pipe 3a 'with a gap slightly smaller than that of the first bubble generating portion A, and wraps the cut portion with the second air inlet pipe 5b. Due to the gap between the air inlet pipe 5b and the water pipe 3a ', the pressure reduction area generated near the position of the cut surface of the water pipe is sucked by the second air inlet pipe 5b and at the same time, further bubbles in the air water mixed water. Is further generated and sent to the spout 2. At this time, the air adjusting valve 6 is attached to the inlet of the upper end of the second air inlet pipe 5b to adjust the inflow of air.

4) outlet

The air-mixed water stream flowing from the bubble generating parts (A, B) is ejected from the discharging port (2) to the bottom (bottom of the ship) (Z), where the ejection outlet (2) It is necessary to reduce the cross-sectional area of the tip of the part. The amount of shrinkage depends on the situation, but about half would be appropriate.

Subsequently, in order to more specifically verify each configuration and function of the apparatus used in the method for reducing frictional resistance of the ship of the present invention, the generation test and the low pressure test of the low pressure microbubble using the model test maker were also tested.

A large object of the present invention is to save energy required for hull propulsion by reducing the frictional resistance generated at the hull receiving surface by generating low pressure microbubbles on the hull receiving surface during the operation of the ship. In particular, in the case of large vessels such as tankers, it is important to send low pressure microbubbles generated by decompression to the bottom of an arbitrary depth so that they are ejected from the spout so as not to be affected by the surrounding hydraulic environment. If the solution of the problem is suggested only by the consistency of, the evidence is scarce. Thus, the summary and results of the experiments and the inferences thus obtained are shown below.

Figure 4 shows the test maker used in the low pressure microbubble generation test, the bubble production site of the test maker is a small mechanism of about 30mm in diameter, even if the size is adjusted to the actual dimensions of the actual large vessels decompression phenomenon It is characterized in that the principle of low pressure microbubble generation using the same. In addition, although the bubble generating apparatus shown in FIG. 5 differs in the positional relationship of the two air inflow pipes, the function is the same.

6 is a schematic diagram of a generation test 1 for low pressure microbubbles. The tester's water pipe is connected to the faucet, and one faucet is the power source of the water flow. In the above test (1), the bubble generation part integrated with the tip was fixed at each position of 2 cm and 60 cm in depth to observe the low pressure microbubbles, and as a result, a large amount of micro bubbles could be generated at a depth of 2 cm. It could not occur at a depth of 60 cm.

This phenomenon indicates that the outside air is drawn into the decompression area around the tip of the water inlet pipe and the air inlet pipe, and the air is not bubbled under the influence of water pressure in the process of being drawn into the water stream and bubbled. From this result, when the bubble generator in Figs. 3 and 4 were physicalized in accordance with the actual dimensions of a large ship and mounted at the position of the hydraulic environment at the bottom level (approximately 10 to 15M), the flow rate of the water flow in the water pipe was increased quickly. Even if it did, it could be inferred that bubble generation would be impossible. In addition, it is necessary to use an air pressurization device such as a compressor when attempting to generate micro bubbles at a water depth of 10 to 15 M, and in this case, it can be easily estimated that low pressure micro bubbles having non-expandable properties can be lost. This reasoning is related to the second task.

Subsequently, the generation test (2) of the low pressure micro bubble was tested using the test manufacturing machine shown in FIG. The test producer has only the tip end portion of the second air inlet pipe of the test maker of FIG. 6 described above extending 4M, and the cross-sectional area of the tip end of the second air inlet pipe 5b of FIGS. 4 and 5 is made small. It is characterized by. The tester's water pipe is connected to two faucets, and the two faucets are the power source of the water flow. The water depth of the tank is 4.5M.

This test (2) was performed as follows. As shown in Figure 8, while the bubble generating part of the test maker is fixed at the position on the water surface, the tip part is fixed vertically at each position of depth of 0.1M, 1M, 2M, 3M, and 4M, and the air is measured using a measuring instrument at each position. The suction rate of was measured. As a result, as shown in Fig. 7, except for the surface surface of 0.1M, there was almost no difference in the amount of bubbles generated. From this result, it was inferred that the same result could be obtained even if the tip was fixed at a depth position deeper than 4M. This reasoning is related to the solution of the second problem. In addition, the rate of air suction at air suction at a depth of 0.1 M is faster than that at other depths because most of the bubbles are ejected directly to the surface because the bubbles are close to the surface.

The measurement method of the bubble generation amount used in the said test 2 is based on the measuring device shown in FIG. (A) is an air inflow measurement balloon (balloon). Since the amount of bubble generation and the amount of air intake in the measuring balloon will be the same, the measuring device is connected to the first air inlet pipe and the second air inlet pipe of the test manufacturer, and the number of seconds from the start of bubble generation until the air in the measuring balloon is empty. The amount of bubbles generated per second was calculated by measuring (see the graph shown in FIG. 8).

An object of the present invention is to reduce frictional resistance by generating low pressure microbubbles on the hull receiving surface during navigation of a ship. As a function of the bubble generator for this purpose, it is necessary to generate bubbles in large quantities. This is because the frictional resistance decreases as the aggregation density of the microbubbles covering the bottom of the ship (bottom of the ship) is higher. For this reason, the bubble generation amount of the test maker was measured by a measuring instrument, but the bubble generation amount at the depth of 4M at the tip was 160 cc / sec and the amount of tap water used was 800 cc / sec. In terms of volume ratio, the amount of water: bubble generation amount = about 5.5: 1. Although it is difficult to evaluate because there is no comparative standard, it was confirmed that a large amount of micro bubbles having a diameter of about 0.01 mm were generated when photographing at a close distance. The bubble generator function of the test machine was considered to be quite efficient. From these experimental results, it was inferred that the same result could be obtained by realizing the tester in accordance with the actual dimensions of a large ship as long as the physical principles of low pressure microbubbles were the same. This reasoning is related to the means for solving the problems of the present invention.

Industrial availability

It can be utilized industrially by establishing and implementing the technique of the bubble generation method in the friction reduction apparatus of the ship of this invention.

One; Water intake
2; vent
3a; water pipe
3a '; water pipe
3b; Brackish water mixing pipe
4; Water pump
5a; 1st air inlet pipe
5b; 2nd air inlet pipe
6; Control valve
7; Air inlet
7a; 1st air inlet
7b; 2nd air inlet
A; Primary bubble generation site
B; Second bubble generation part
X; Athlete (prow)
Y; waterline
Z; Bottom (bottom of the boat)

Claims (1)

In the frictional resistance reduction apparatus of the ship,
Inlet near waterline and receiving natural water flow along the ship's heading direction, and inlet near the ship,
It is connected to one continuous pipe which consists of a water pipe and a water mixing pipe.
A water pump is mounted in the water pipe at the same level of water as the water inlet behind the water inlet;
The rear water pipe is located at the stern side of the water pipe which is piped toward the stern direction so as to be located above the vicinity of the waterline.
When both pipes overlap inside and outside than the water pipe, the tip of the first air inlet pipe of thin thickness having a narrow gap is bent in the water direction, and the water pipe is inserted through the water pipe.
At the position where both pipes are parallel, the tip of the first air inlet pipe is cut off,
The surrounding area or the vicinity of the position is the primary bubble generating site,
Subsequently, an adjustment valve is mounted on the rear side, and the second air inlet pipe is thick so that a narrow gap occurs when the water pipe overlaps the inside and the outside of the water pipe.
The water pipe is cut at the position where both pipes are parallel, and the peripheral area or the vicinity of the position is the secondary bubble generating site,
The second air inlet pipe is connected to the outlet as a rider mixing water pipe for sending the air water mixed water stream in its extended form after the position,
Inflow water from the intake port sucks air from the first air inlet pipe and the second air inlet pipe by using a pressure reduction phenomenon against the atmospheric pressure generated at the first bubble generation site and the second bubble generation site.
With the air water mixed stream which generates low pressure microbubbles and is ejected from the brackish mixed water pipe,
The bubble generation method in the frictional resistance reduction apparatus of the ship characterized by blowing at a jet port.

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