Numerical Analysisof Blending ProcessesofPlastic Bonded Explosivesby Twin Screw Extruder

摘要

In this study, a CFD model has developed to analyze flow pattern and particles behavior for the blending process of PBX by TSE.The mixing efficiency for particles was evaluated in terms of distributive mixing and dispersive mixing.The motion of particles injected to extruder was shown for distributive mixing and Manas-Zloczower mixing index was introduced for dispersive mixing.Dynamic mesh, immersed boundary method, and Discrete Phase Method (DPM) are used for numerical approach to investigate screw rotation situation and particle motion.Six kinds of screw arrays were assumed for the analysis which are differentiated with respect to kneading block array to show the mixing effect and the role of each kneading element.As a result, we confirmed the screw which has each 515R block, 515N block and 515L block is the optimal design for mixing.Also 515N block showed the maximum mixing efficiency for both mixing scheme.The maximum value of cross sectional averaged mixing index was 0.58.For other kneading blocks, 515L block was better than 515R block in terms of distributive mixing but the maximum value of cross sectional averaged mixing index of 515R block was higher than 515L block as0.01.