3D Flow Field Analysis of a Banbury Mixer

Abstract

Abstract Banbury mixers are widely used in polymer processing. The flow field in the chamber of an internal mixer is difficult to analyze due to the complex geometry and transient character of the flow. In this work, a fluìd dynamics analysis package – FIDAP, using the finite element method was employed to simulate the flow patterns in a BB-2 type Banbury mixer. A 3D flow analysis was carried out for the whole mixing chamber. The problem of time dependent flow boundaries was solved by selecting a number of sequential geometries to represent a complete mixing cycle. The flow field was characterized in terms of velocity profiles, pressure contours, shear stresses generated and a parameter λ quantifying the elongational flow components. The last two parameters are the most important ones in analyzing mixing efficiency. The influence of processing conditions (rpm, speed ratio, and initial relative position of the two rotors) on the flow characteristics was analyzed. The flow results from the 3D model were also compared with results previously obtained from a 2D model.