Anti-bubble drag reduction method and system for ships

Abstract

The invention discloses a ship drag reducing method and system through using reverse bubbles. The method involving a reverse bubble generating device, and a reverse bubble transmitting device, whereinthe reverse bubble generating device is used for generating reverse bubbles and stored with first liquid. The steps comprise that inflating the reverse bubble generating device with gas, and then with a set speed, adding dropwisely second liquid into the device to generate suspended liquid droplets on the liquid surface; further, increasing the dropping speed to send the suspended liquid dropletsinto seawater to generate the reverse bubbles, wherein each reverse bubble is a gas-liquid structure, namely liquid contains gas films and the gas films are provided with the liquid; and finally, utilizing the reverse bubble transmitting device to transfer the reverse bubbles generated in the reverse bubble generating device on the surface of a ship body. According to the ship drag reducing method and system through using the reverse bubbles, the reverse bubbles are used for replacing common bubbles to realize ship drag reducing, which leads to a new drag reducing method; and by designing a special reverse bubble generating device to generate the reverse bubbles, the effect of ship drag reducing can be realized.

Description

technical field [0001] The invention relates to the field of ship air bubble drag reduction, in particular to a ship anti-bubble drag reduction method and system. Background technique [0002] Globally, ship bubble drag reduction technology has been studied for decades, but it has not been widely used on ships, and most of the research is still in the model test stage. This technology has the following problems: [0003] 1) When it is applied to high-speed ships, the air resistance is very large when the ship sails at high speed, and the water friction resistance of the ship is only 20% to 30% of the total resistance, so the actual effect of air bubble drag reduction is not great. Moreover, due to the low power of the main engine of the ship, the energy-saving effect and low-carbon social benefits are lower than those of high-power transport ships. [0004] 2) When the low-speed transport ship is sailing, due to its low speed, some air bubbles escape before covering the hul...

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Problems solved by technology

[0003] 1) When it is applied to high-speed ships, the air resistance is very large when the ship sails at high speed, and the water friction resistance of the ship is only 20% to 30% of the total resistance, so the actual effect of air bubble drag reduction is not great

Moreover, due to the low power of the main engine of the ship, the energy-saving effect and low-carbon social benefits are lower than those of high-power transport ships.

[0004] 2) When the low-speed transport ship is sailing, due to its low speed, some bubbles escape before covering the hull, the effective coverage area of ​​the bubbles is small, and the drag reduction effect decreases

At the same time, low-speed transport ships often have a relatively deep draft. As the draft of the ship increases, the contact area between the side of the ship and the water increases, and the proportion of the bottom resistance to the total frictional resistance decreases, and the drag reduction effect is greatly reduced. Bubbles are easy to escape during drag reduction. If you want to get a more ideal drag reduction effect, you need a large amount of air injection, which in itself will consume a lot of energy, making the overall energy saving effect not good.

[0005] 3) Bubbles diffuse into the propeller, that is, the water flow mixed with gas enters the functional area of ​​the propeller, which will seriously interfere with the function of the propeller, accelerate the erosion of the propeller, cause damage to the propeller structure, and reduce the propulsion efficiency of the ship

[0006] 4) When the air bubbles burst, large cavitation will be caused to the hull and the paint layer on the surface of the hull will fall off. Therefore, many shipowners are cautious about adopting this solution

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