Abstract
The paper develops a method based on the thermal effects caused by pressure drop, internal friction, external friction and convection, for polymer melts pressure drop calculation in non isothermal melt flow through the channels. The whole thermal effect is equivalent with a supplementary pressure drop Dp (T). Later on Dp (T) generates a supplementary length L (T). This value is added to the initial channel length and an equivalent length, taking into account the thermal effects, Lech , is obtained. By substitution of the length L in isothermal pressure drop relation, with length Lech, the new relations may be applied for non isothermal flow melts. The equivalent length concept is applied to a real case. Keywords: nonisothermal polymer flow, rheology, polymer mold design, polymer melts pressure drop