Collect. Czech. Chem. Commun. 1980, 45, 2510-2515

The flow of a plastic material in ducts

Kamil Wichterle and Ondřej Wein

Institute of Chemical Process Fundamentals, Czechoslovak Academy of Sciences, 165 02 Prague 6-Suchdol


The kinematics and dynamics of the flow of an ideally plastic material is fully characterized by the cross section occupied by the flowing material. It will be shown that appart from the case when the flowing material occupies the total cross sectional area of the duct, nontrivial cases exist with part of the cross section occupied by a stagnant material adhering to the walls. For the calculation of pressure losses it is then usefull to characterize the cross section of the duct by the value of the maximum hydraulic radius.