Numerical Models For Printing And Coating Flows
A number of papers are presented covering the issues summarised in the preceding paragraph. The first paper by Powell, Savage and Guthrie describes their current work on filamentation at the point of film splitting, focusing on the behaviour where one surface is engraved. Their model accounts for the tensile stresses in the filament, its profile, adhesion and final detachment. The second paper is by Bohan, Gethin and Claypole in which they explore the inclusion of a roughness model in rolling soft elastohydrodynamic contacts. In this work the roughness interaction is included directly through the prescription of a local film thickness and the ability of the approach to treat real roughness profiles is demonstrated.
The third and fourth papers are by Chandio and Webster in which they explore numerical techniques to model the reverse roller coating process, including both steady and transient conditions. This presents challenges in the handling the deflection of a thin substrate that deflects laterally in response to the loads generated in the coating nip and in the need to determine automatically the position of the free surface in the nip. The fourth and fifth share the theme of wire coating. The fourth reports the work of Matallah, Townsend and Webster and the fifth the development undertaken by Baloch, Matallah, Ngamaramvaranggul and Webster. These papers focus on the requirement to include complex rheology models to represent the behaviour of the polymer system together with die swell prediction as the product emerges from the coating die.
The sixth paper also explores the benefit of using multiprocessor systems to perform simulation, demonstrating the ability to undertake more complex and demanding simulations efficiently.
The issue is conclude by a paper by Bohan, Fox, Claypole and Gethin in which the authors explore the application of models to represent coating systems supplied by non-Newtonian fluids. The model proposed is capable of accounting for the local shear thinning behaviour that takes place in the plane of the nip junction. The impact on coating performance is demonstrated through a number of case studies. All of these studies highlight fluid-structure interactions that take place together with the treatment of free surfaces. The issue brings together some of the most recent work addressing these details that are generic to printing and coating applications.
Previously published in: International Journal of Numerical Methods for Heat & Fluid Flow, Volume 12, Number 4, 2002
183 pages; ISBN 9781845446307
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Title: Numerical Models For Printing And Coating Flows
Author: D.T. Gethin