Super-hydrophobic surface gas film regulation and control device based on near-wall surface gas saturation regulation

Abstract

The invention provides a super-hydrophobic surface gas film regulation and control device based on near-wall surface gas saturation regulation. A super-hydrophobic coating, a hydrophilic base material, a power supply, electrolysis electrodes or heating elements and the like are used, and gas saturation in water close to a wall surface is regulated and controlled through he modes of water electrolysis reaction, wall surface heating and the like, so that a water body reaches a gas saturation state or even a supersaturation state; and three-phase contact lines for constraining a gas film are alternately arranged on a super-hydrophobic surface and a hydrophilic surface, the electrolysis electrodes or heating elements are located in a hydrophilic area with a smooth surface, and the super-hydrophobic area does not need to contain special functional elements; the gas film can be automatically sealed and stored in a super-hydrophobic surface microstructure, and gas dissolved in the supersaturation state can diffuse into the gas film spontaneously, so that free bubbles cannot be separated out in the smooth hydrophilic area or in the water body, and thus the influence of buoyancy, surface tension and the like on a gas supplementing effect is overcome.

Description

technical field [0001] The invention relates to a super-hydrophobic surface gas film regulation device based on near-wall gas saturation regulation, in particular to a submerged super-hydrophobic surface gas film permanent maintenance and shape regulation device, which belongs to the technical field of drag reduction. Background technique [0002] Superhydrophobic surfaces are defined as surfaces on which the static contact angle of droplets is greater than 150° and the rolling angle is less than 10°. In recent years, it has been found that superhydrophobic surfaces have excellent drag reduction performance underwater. The fundamental reason for the drag reduction effect of the superhydrophobic surface is that the micro-nano rough structure distributed on the surface can bind a layer of gas film underwater, replacing the traditional solid-liquid contact interface with a solid-gas-liquid composite contact interface, and the liquid is on the gas-liquid interface. Speed ​​slip ...

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Problems solved by technology

The invention patent "an engineering surface that improves the ability to lock bubbles underwater and its preparation method (CN201810384589.8)" and the invention patent "air film drag reduction model based on wettability regulation and its manufacturing method (CN201510579215.8)" both It is proposed to locally modify the superhydrophobic surface, and the constructed superhydrophobic-hydrophilic surface structure can effectively bind the three-phase contact line of the gas film, thereby achieving a stronger gas film binding ability than the ordinary superhydrophobic surface. It is also possible to further control the morphology of the gas-liquid interface, but these methods cannot overcome the problems of gas film dissolution and loss damage; the invention patent "method and device for restoring and maintaining superhydrophobicity under liquid (CN201180046655.7)" and "A Drag Reduction Model of Air Film on Super-hydrophobic Surface Based on Dynamic Gas Supplementation of Electrolyzed Water (CN201611112056.1)" proposes to use electrolyzed water to generate gas to maintain the stability of super-hydrophobic air film for a long time, and it can automatically replenish and regenerate after the air film is lost and destroyed. recovery, which overcomes the problem that the air film cannot be maintained stably for a long time, but both of these two patents involve micro-nano processing technology that requires extremely high processing precision. The microstructure of the super-hydrophobic surface must meet specific requirements, otherwise the buoyancy and surface Under the action of tension, the bubbles generated by electrolysis will break away from the surface, causing gas loss and gas film recovery failure; high-cost materials including micro-nano electrodes and platinum electrodes are also used, so they are not suitable for large-scale engineering applications; in addition, the two inventions Because the power circuit will be automatically cut off during the recovery process of the gas film, the shape of the gas film is relatively fixed, and there is a lack of precise and effective regulation of the shape of the gas film

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