Abstract: Based on elongation flow mechanism, structure improvement was carried out on the disc face of traditional series disc extruder. Numerical simulation was carried out on the disc mixing section using CFD software POLYFLOW, and comparative study was performed between taper-face disc and flat-face disc on the shearing rate, stretching rate, instantaneous stretching efficiency and time-averaged instantaneous stretching efficiency, and the effect that disc clearance and disc ledge have on the elongational flow of the taper-face disc. The simulations showed that melt particles in taper-face disc runner took an irrotational flow, experience larger actions governed by elongational flows and shear flows, and get better instantaneous and time-averaged efficiency of stretching compared with traditional disc. Moreover, there existed a proper distance between discs and disc ledge for getting stronger elongational flow.

Key words: series disc extruder, cone disc, stretching efficiency, numerical simulation, statistical analysis