Visualisation and analysis of the flow along the kneading block of a twin-screw extruder

Olga Sousa Carneiro (1) , Arnaud Poulesquen (2) , José Antonio Covas (1) , Bruno Vergnes (2)

1 Universidade do Minho = University of Minho [Braga]
2 CEMEF - Centre de Mise en Forme des Matériaux

The flow of a silicone oil of high viscosity along a block of staggered kneading discs of a co-rotating twin screw extruder was investigated with the use of an acrylic transparent barrel. A digital video camera recorded the flow path of a red dye, dispersed in the silicone oil, along the screws and in the intermeshing zone. Different geometrical configurations were studied, namely various staggering angles (+30degrees, 90degrees and -30degrees) and thicknesses (7.5, 15.0 and 22.5 mm) of kneading blocks. The effects of these geometrical parameters on the pressure generation and filling ratio were investigated. It was observed that, even for negative staggering, the filling ratio of the kneading block was lower than one. Based upon these experiments, analytical expressions describing the filling ratio as function of geometry (staggering angle, thickness and number of discs) and operating conditions (feed rate and screw speed) were derived.

Domaines: Matériaux

Olga Sousa Carneiro, Arnaud Poulesquen, José Antonio Covas, Bruno Vergnes. Visualisation and analysis of the flow along the kneading block of a twin-screw extruder. International Polymer Processing, 2002, 17 (4), p.301-308. ⟨hal-00533188⟩