The influence of viscoelastic rheology on blade coating as revealed by numerical methods

Abstract

. The influence of an elastic component of the rheological properties of the coating suspension on the coating flow in the blade coating process was investigated by numerical methods. The Giesekus model was used as the constitutive equation for the coating fluid (coating colour). The system of time-dependent partial differential equations was solved numerically by discretising the solution with finite differences on an overlapping composite grid. The numerical results reveal that the elastic behaviour of the coating colours, characterized with a relaxation parameter, can have a decisive effect on the behaviour of the coating colour in the vicinity of the blade tip. The calculated colour-related forces acting on the surface of the substrate and on the blade tip were lower with a viscoelastic colour than those emanating from a corresponding simulation using a Newtonian colour. 1 To appear in Nordic Pulp and Paper Research Journal. 2 Also at Royal Institute of Technology, Center for Co...