JPS62286886A - Reducing device for friction resistance of ship - Google Patents

Abstract

PURPOSE:To promote the reduction of friction resistance of a ship body, by mixing exhaust gas from an engine exhaust gas cooler with seawater, sucked from a suction device, in a mixer to be injected into a submerged part of the ship body from an injection nozzle in the front part of the ship body. CONSTITUTION:Exhaust gas of a main engine 1 is inducted to a cooler 3 through exhaust gas pipes 2A, 2B and cooled thereafter supplied to a mixer 6 through a compressor 5. Seawater, sucked by a suction pump 8 from a sea chest 7 in the bottom of a ship, is supplied to the mixer 6. The exhaust gas, mixed with the seawater in the mixer 6, is injected through a pipe 9 into a submerged part of the ship from an injection nozzle 10 provided in a bow part. In this way, friction resistance of a ship body can be effectively reduced by coating surfaces of the submerged part of the ship body with fine bubbles.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a device for reducing frictional resistance of a ship during navigation.

(Prior Art and Problems) It is known that 60 to 70% of the total resistance of a sailing ship is due to friction between the ship's surface and seawater. Although wave-making resistance and the like have been reduced through the progress of research based on theory and experiments, reduction of the above-mentioned frictional resistance is not easy at this stage because its cause is simple.

As a measure to reduce the above-mentioned frictional resistance, for example, it is known to mix polymer compounds into seawater, but this is accompanied by a major problem of marine pollution, and furthermore, it requires a large amount of polymer compounds, resulting in high costs. This is difficult to realize due to the disadvantages such as:

On the other hand, it is also known that frictional resistance can be reduced by incorporating microscopic air bubbles into the seawater layer that is in contact with the surface of the hull.

However, there are unresolved problems, such as the fact that an appropriate means for generating minute bubbles has not yet been devised, and the power required to blow out the bubbles requires a large amount of energy.

(Means and effects for solving the problems) An object of the present invention is to solve the above-mentioned conventional problems and to reduce the frictional resistance of the hull by making it possible to generate microbubbles with a simple device. This is what I did.

In order to achieve the above object, the present invention connects an engine exhaust gas cooling device and a seawater suction device to a mixer, and connects the mixer to an injection nozzle provided on the front surface of the hull, so that the exhaust gas is mixed. and injecting seawater into the sea from the injection nozzle.

In the present invention as described above, the higher the pressure of the exhaust gas and the lower the temperature, the easier it is for the exhaust gas to mix into the absorbed seawater. Therefore, when high-pressure gas from an engine such as the main engine is cooled in the cooling device, the exhaust gas is very well mixed into the seawater sucked in from the seawater suction device in the mixer. When seawater mixed with such exhaust gas is injected into the sea from an injection nozzle, the pressure decreases and a large number of microbubbles are generated. As the ship moves forward, the microbubbles come to wrap around the ship, reducing the frictional resistance between the ship and the seawater.

In the present invention, when the injection nozzle is installed at the bow of the ship, the seawater pressure near the injection nozzle increases due to the flow velocity during navigation, so it is necessary to use a large injection pressure to inject seawater mixed with exhaust gas. Requires. Therefore, if a protective plate is installed in front of the injection nozzle at a distance from the injection nozzle to protect the injection nozzle from ocean currents, the above seawater pressure will not become so high, and the injection pressure will also be significantly higher. do not need. Furthermore, when a protective plate is provided, the nozzle pipes can be arranged in the space between the outer plate of the hull and the protective plate, so there is no need to provide a large number of injection nozzle ports on the outer plate. Providing a large number of nozzle ports directly on the outer shell is not preferable for processing and strength reasons of the outer shell, and the above-mentioned drawing out of the nozzle tubes to the outside of the ship is extremely effective.

(Example) An example of the present invention will be described below based on the accompanying drawings.

FIG. 1 is a schematic configuration diagram of the apparatus of this embodiment.

In the figure, 1 is a main engine that rotates a propeller 3 via a propulsion shaft 2.

Each exhaust gas pipe 2A, 21) of the main engine 1. ... are collected into one pipe 2 and guided to a cooling device 3. In this cooling device, the pipe 2 is cooled by cold water sprayed from a cooling pipe 3A. The cold water may be specially prepared by another device, or a portion of seawater absorbed from a seawater suction device 7, which will be described later, may be used.

The cooling device 3 is connected by a pipe 4 to a mixer 6 via a compressor 5. Note that the compressor 5 is not necessarily required when the exhaust gas is sufficiently high, and the cooling device 3 may be directly connected to the mixer 6.

On the other hand, a sea chest 7 is provided at the bottom of the ship as a seawater suction device, and the sea chest 7 is connected to the mixer 6 via a suction pump 8. The mixer 6 has stirring means to mix the exhaust gas into the seawater.

The mixer 6 is connected to an injection nozzle pipe 10 by a pipe 9 extending to the bow. The injection nozzle pipe 10 extends vertically along the outer plate of the bow, and is provided with a plurality of nozzle ports at appropriate pitches. In addition, the injection nozzle pipe 10
As can be seen in Figure 2, protective plates 1) are attached to the outer shell at appropriate intervals in front of the ship to prevent sea currents caused by the ship's progress from directly reaching the injection nozzle pipe and interfering with injection. There is no such thing.

The apparatus of this embodiment as described above operates as follows.

First, exhaust gas from the main engine 1 that drives the propeller 3 is led to the cooling device 3 through the pipe 2, where it is cooled by cold water sprayed from the cooling pipe 3A. Thereafter, the exhaust gas is conveyed to a compressor 5 via a pipe 4, compressed as required, and then conveyed to a mixer 6. Note that if the exhaust gas is already at a sufficiently high pressure, it is sent directly to the mixer 6 without passing through the compressor.

On the other hand, seawater is sucked from the sea chest 7, and the pump 8
is sent to the mixer 6.

In the mixer 6, the cooled high-pressure exhaust gas and the seawater from the sea chest are sufficiently mixed by stirring, resulting in a state in which the exhaust gas is mixed with the seawater.

This seawater mixed with exhaust gas is sent through a pipe 9 to a nozzle pipe 10 provided on the outer plate of the bow section, and is jetted into the ship from a plurality of nozzle ports every t. At this time, a protection Fi, 1) is provided in front of the nozzle pipe 10, so that ocean currents caused by the progress of the ship do not directly hit the nozzle pipe 10, so that seawater mixed with exhaust gas is not ejected from the nozzle opening. There will be no hindrance.

The pressure of the exhaust gas mixture injected into the sea from the nozzle port of the nozzle pipe 10 decreases in the sea, producing countless microbubbles, which surround the bow of the ship. Riding the flow generated by the ship's progress, the bubbles travel along the ship's hull to the stern and envelop the entire hull. In this way, the frictional resistance in the sea is drastically reduced.

(Effects of the Invention) As described above, the present invention cools high-pressure exhaust gas, mixes it with seawater from a sea chest, etc., and then blows it out from the front of the ship. can be easily obtained, and the frictional resistance of the hull is drastically reduced, resulting in the effect of improving the overall cruising duration. Moreover, no consumable materials are required for generating the bubbles, which is advantageous in terms of economy, and furthermore, there is no problem of seawater contamination.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an apparatus according to an embodiment of the present invention, and FIG. 2 is an enlarged plan view showing the bow portion of the ship in which the nozzles and the like shown in FIG. 1 are arranged. 1... Engine (main engine) 3... Cooling device 6... Mixer 7... Seawater intake Device (sea chest) 1
0......Injection nozzle (pipe) 1)...
・・・Protection plate

Claims (2)

[Claims] (1) Connect the engine exhaust gas cooling device and the seawater suction device to a mixer, connect the mixer to an injection nozzle provided on the front surface of the hull, and direct the seawater to be mixed with the exhaust gas into the sea from the injection nozzle. A device for reducing frictional resistance on ships. (2) The injection nozzle is protected from ocean currents accompanying the progress of the ship by a protection plate placed in front of the injection nozzle with a space therebetween.
1) A frictional resistance reducing device for a ship as described in item 1).