Determination of pressure loss during flow of visco-plastic mixtures in horizontal pipelines in the laminar flow zone

The paper shows a method of determination of pressure loss during flow of the visco-plastic mixtures in pipelines on the basis of dimensionless criterion λ(Regen). In order to describe their rheological characters, the 3-parameter generalized Herschel-Bulkley and Vočadlo models were applied. Possible applications of simplified formulas for calculation of the generalized Reynolds number for both considered rheological models were analyzed. The analysis give a range of relative error for assumption that yield stress τo in the laminar flow zone has been omitted in calculations.