Abstract
The ways leading to the increase of the flowrate of an extruder of a given geometry are examined, while considering the real situation: screw is rotating and the barrel is stationary; the granules slide onto the surface of the screw; in the granules’ relatively thick layers, relative motion takes place, equivalent to a velocity gradient. Reference was made to the granular material in the feeding zone, to the parameters specific to the feeding zone and their influence on the flowrate, through the values of the friction coefficients onto the barrel and screw (flowrate is proportional with the term , hence an increase in this term in a given case will lead to an increase in the flowrate value). The influence of both the grooves in the feeding zone and of the angle between the direction of movement of the granules and the position of grooves onto the interior surface of the barrel was analysed. There was also considered the posibility of increasing the flowrate through the increase in the bulk density of the granules in the feeding zone, while considering the influence of pressure as well as the ratio between the depth of the screw channel in the feeding zone (adjustable using grooves) and the granules’ diameter. Keywords: extruder floerate, friction coefficient, bulk density, pressure