ブレードコーティングの際に生じる自由表面を有する塗工剤の流れと液膜の厚さ 〔流体工学, 流体機械〕

Viscous free surface flows with a blade of various inclination angles are studied using Finite Difference Method. Consideration is restricted to the steady two-dimensional Stokes flow of an incompressible Newtonian liquid carried out of a narrow gap by a moving plate. The flow upstream is represented by Taylor-Hamel solution and the flow downstream by Coyne-Elrod solution, whose unknown constant k is determined in this study. And so, the flow downstream except a small part in the vicinity of blade edge can be described analytically. Free surface meniscus, velocity profile and so on are calculated numerically. Investigation shows that the effect of blade angle on free surface flow is diminishingly small. To this peculiar result, the physical explanation is given by a qualitative estimation for the system of the governing equations. Consequently, uniform value of pressure far upstream, about which little attention has been paid heretofore, is revealed to be an important factor affecting film thickness. Adopting this quantity as one of the parameters makes it possible to predict the film thickness.