帘式涂布颜料涂料在模头内的流场分析

Flow Field Analysis of Paper Curtain Coating Within the Die

采用Fluent软件对颜料涂料在帘式涂布模头内的流场进行了数值模拟,并分别探究了颜料涂料固含量及温度对模头歧管处涡流,模头出口处流速的横向分布均匀性及模头内压力降等方面的影响。结果表明,颜料涂料在歧管处的剪切速率范围为100~300 s^–1,不易产生涡流;其流变性的增大会破坏出口处流速横向分布的均匀性,单位宽度流量最大差值与平均单位宽度流量的比值A均大于5%;但由于颜料涂料较大的流变性,颜料涂料在模头内的压力降较小,介于1.2×10^5~3.1×10^5 Pa之间。

Fluent software was utilized for the flow field simulation analysis of pigment coating in the curtain head.The influences of pigment coating’s solid content and temperature on the eddy at the die manifold,velocity uniformity at the die outlet,and pressure drop were investigated respectively.The results showed that the shear rate of pigment coating at the manifold ranges from 100~300 s^–1,which was not easy to generate eddy.The increase of its rheological property would worsen the evenness of the transverse distribution of velocity at the outlet,and the ratio A between the maximum difference of flow rate per unit width and the average flow rate per unit width was greater than 5%.Due to the large rheological property of pigment coating,the pressure drop of pigment coating in the die head was small,range from 1.2×10^5~3.1×10^5 Pa.