Study On The Process Of Air-knife Jet Wiping On The Cold Rolling Hot-dip Galvanized Sheet

In hot-dip galvanizing process, excess liquid zinc was wiped off by the highspeed jet flow generated by air knife, so air jet wiping control are so crucial part todetermine the coating thickness and uniformity of the zinc layer on the strip. Duringgalvanizing edge overcoating (EOC) may occur near the edge of the strip, which notonly causes the waste of zinc but also brings about serious effect on downstreamprocesses. Studying the process of air-knife jet wiping on the surface of strip hasimportant theoretical and application value about weakening the phenomenon of edgeover coating.The main purpose of this thesis is to study the influence factors on the process ofair-knife jet wiping on the cold rolling hot-dip galvanizing sheet with numericalsimulation combined with laboratory and work site experiments. The distributions ofstatic pressure on the strip were calculated by Fluent numerical simulation software,and the influences of air knife、baffle and strip itself at the different conditions wereanalyzed, and then the actual pressures on the strip were measured by work siteexperiments to study the disciplines of pressures on the strip combined withlaboratory methods.The main content of this thesis includes three parts:The influences on the edge pressure of strip by the strip width, the strip speed,the strip thickness, the distance between baffle and edge of the strip, as well as thecombined function of baffle and wedge nozzle slot under different conditions werediscussed in the first part.The distribution of pressure along the width of the resin board is measured bypressure sensors in the laboratory. A simulated device that refers to the real equipmenthas been made for studying the process of air-knife jet wiping the surface of strip steelin the second part.The distribution of pressure along the width of the strip is measured by pressuresensors in the work site to obtain the discipline on the distribution of pressure alongthe surface of strip under different conditions in the third part.