某结冰风洞喷雾系统循环法酸洗钝化

Circular Pickling and Passivation Process for Spraying System in an Icing Wind Tunnel

为提高某结冰风洞喷雾系统使用寿命,避免雾化喷嘴在使用中发生孔径改变或堵塞,交付风洞安装前需对喷雾系统整体进行酸洗钝化。根据系统结构特性分析和耐酸性试验结果,酸洗钝化常用的浸渍法、膏剂法、喷淋法等无法用于该系统,而循环法也不适于这种末端开放式系统。经分析验证,以PU管、乳胶管替代喷雾系统中结构精密和不耐酸蚀的器件管件,用PU管、乳胶管、酸液集液管、酸液收集罐和低压耐腐蚀泵将喷雾系统组成可使酸液循环的封闭式系统。室温条件下,以硝酸、氢氟酸和Lan-826配伍为酸洗液,体积分数40%硝酸为钝化液,用循环法对系统进行了酸洗钝化,得到了合格的钝化膜。

The pickling and passivation of spraying system is essential before it is installed in an icing wind tunnel, which would prolong the service life of spraying system and avoid dimeter variation and clogging of the nozzle in the system. The pickling and passivation process used commonly includes dipping process, pickling ＆ passivation paste process and acid spray process. According to the structure characteristic analysis and acid test result, these processes can not be used in the spraying system. Circular pickling and passivation process seems unsuitable yet because the spraying system is an open ended system. In the final solution, latex tube and polyurethane tube were used to replace acid nonresistant devices, and an acid closed cycle system was composed of latex tubing, polyurethane tube, collector tube, acid tank and low pressure anticorrosion pump. Thus circular pickling and passivation process can be used in the spraying system. The pickling solution at room temperature was comprised of nitric acid, hydrofluoric acid and Lan- 826. The passivation solution was 40vol% nitric acid. A stable passive film was obtained in such circular picking and passivation process.