UBC Theses and Dissertations
A numerical investigation of the pressure distribution on a Fourdrinier paper machine drainage foil Lepp, Gary
A mathematical model and three numerical solution procedures have been developed to predict the pressure distribution on a Fourdrinier paper machine drainage foil. The present models are based on a numerical solution of the full laminar boundary layer equations. Previous modelling attempts have made use of the boundary layer equations in various simplified forms. The solution procedures used were grouped into two categories; the one-dimensional models and the two-dimensional model. The one-dimensional models were based on an approximate integral solution of the boundary layer equations. The two-dimensional model was based on a solution of the boundary layer equations using a finite difference method. Experimental measurements of the pressure distributions and the drainage rates on three tapered foils and two stepped foils were made to provide data for comparison with the results of the models. Computed results obtained using the solution procedures generally did not agree well with the experimental results of the present investigation. The results, however, did predict observed trends in the pressure distributions due to variations in the wire velocity and foil geometries. Consequently, the models may be considered viable approaches to predicting the pressure distribution on a foil, though a great deal of further work is necessary before the solution procedures may be used for design purposes.
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