FLOW OF WOOD PULP FIBER SUSPENSIONS IN OPEN CHANNELS

Open channels have been used in the pulp and paper industry for fibre suspension containment, tree log transport, spillage and storage tank overflows and effluent removal. Open channels could have other uses su ch as in steep bleaching, but no engineering design data or methods ha ve been proposed in the technical literature. Flow data were obtained in four rectangular channels for water and a bleached pine kraft fibre suspension at pulp concentrations ranging from 0.5 to 2.25 per cent w hen flowing in channels of various widths at slopes ranging from 1 deg rees to 10 degrees. Various flow mechanisms were deduced from visual o bservations and are described. A logarithmic resistance formula simila r to the Prantl-Karman-Nikuradse equations for pipe Row was used succe ssfully to model the flow resistance. Linear correlations were obtaine d at each fibre concentration, channel width and slope. Coefficients i n the equation were found to be a function of pulp concentration, chan nel slope, width and surface roughness. The equation provides a basis for open channel design.