The Study In Drug-reduction Effect Of Lowe Surface Energy Film On Underwater Craft

When ships or underwater crafts move, there are three kinds of resistances which are wave making resistance, pressure resistance and tangential resistance (tangential resistance comes from the resistance between craft and the surrounding water) . In these three resistances, tangential resistance is the greatest. In recent years, the researches of the shark skin with excellent effects of drag reduction play an important role in promoting the development of the drag reduction technology from the perspective of bionics. The surface processing on the ship, especially on underwater craft by surface engineering, can effectively reduce tangential resistance when traveling. In this issue, we mainly study the low surface energy coating which is super-hydrophobic (the surface whose water contact angles is over 150° is called super-hydrophobic), and the special structure which is in micron dimension and formed on its surface, takes an important role in drag reduction on the surface ofunderwater craft.The main research can be divided into tow parts:1. The process of making super-hydrophobic surface:a. Hydrophobic thin film can be prepared by the way of shaping micro-nano structure, and then decorate it with solutions FAS which has the low surface energy and is employed as hydrophobic agent. In order to shape micro-nano structure on metal board two ways are introduced in this article which are etching by strong acid and anodic oxidation. The water contact angle of the film is above 150° and rolling angle is less than 5°. The thickness of FAS layer is 100nm.b. Another way to produce low surface energy film is pre-processing the substrate metal board and then spraying new type F-C dope on it.c. The contact angles of prepared film are measured, and then the results are used to compute the surface energy, the dispersive part and the polarity part of it.2. The drug reduction effects of low surface energy film and micro structure on the surface of underwater craft:a. We have researched the drag reduction effects of surface structure, low surface energy, different dispersive weight and polarity weight of the energy, by recording the change torsion of processed rotary sample in...