Comparison of calculated with measured flow fields in the gap between two rotating rolls

Abstract

Velocity, pressure, temperature, and stress fields are calculated for the flow of a polymer between two counterdirectionally rotating rolls. The rheological behavior of the polymer is described by the Carreau equation, while elasticity is neglected. The results of the numerical calculations are compared with measurements. The stress field is measured by the birefringence method. The local principal stresses in the fluid are determined from the measured anisotropy of the sheared fluid for the penetrating monochromatic light by means of the stress optical law. The equations of motion and continuity are solved with a Finite Element Method (FEM) based on the Galerkin weighted residual method. The computer code is combined with a Boundary Element Method (BEM) algorithm using the Dual Reciprocity Method (DRM) to solve the coupled equation of energy. Results are shown for a shear-thinning polyisobutene melt in a calender with totally submerged rolls. The calculated results for the principal stress differences are compared to the measured results and confirm fairly well. The influence of friction is discussed. 0 1994

Computational fluid dynamics simulation of the roll‐to‐roll coating process for the production of thin film composite membranes including validation

“…[11][12][13][14] With the rise of information technology and faster computational resources, the phenomenon was also tackled with CFD, often solved with finite element methods. [15][16][17] A large part of the work was motivated by problems that arise when applying this coating technique for coatings of paint, organic photovoltaic or semi-conductor materials.…”