连续热镀锌楔形气刀对镀层均匀性的影响

Effect of wedge air knife on uniformity of zinc coating in continuous hot-dip galvanizing process

利用流体力学计算方法，对连续热镀锌气刀射流拭锌过程中带钢表面气流压力和温度分布进行了仿真研究。模拟结果表明：气刀喷吹时，带钢边部5mm范围内出现压力衰减，且边部散热较中心处快，易使带钢出现边部过镀锌缺陷；为避免该缺陷发生，设计了增大边部开口度的楔形刀唇结构气刀，有效阻碍了带钢边部压力衰减，且边部镀层减薄率随楔形开口度的增加而线性增加；对于平行段开口度为1．10m121的气刀，边部开口度选定为1．18～1．22mm，有利于改善镀层均匀性。

The distribution of impinging jet pressure and temperature on the surface of strip steel in continuous hot-dip galvanizing gas-jet wiping process was simulated by computational fluid dynamics method. Simulation results show that the edge over coating defect is more likely to happen due to the pressure decreases in 5 mm range of steel strip edge and the heat dissipation in the edge is relatively faster than that in the central region. To prevent edge over coating, wedge lip edge openmouthed size of air knife was increased. The edge pressure decreases can be effectively impeded by using the air knife, and the edge coating thinning rate increases linearly with the linear growth of wedge openmouthed size. As the parallel section width is 1.10 mm, the uniformity of zinc coating is improved when the wedge openmouthed size is from 1.18 mm to 1.22 ram.