We discuss the mixing characteristics of different kneading blocks based on the numerical simulation of non-isothermal polymer melt flow. The distributive and dispersive mixing is assessed by using finite-time Lyapunov exponent and the mean stress during residence. In addition, the flow patterns associated with the different geometry of the mixing elements are quantified by the strain-rate state. Our approach is found to be useful to evaluate essential difference of mixing characteristics between the conventional kneading discs element and pitched-tip kneading discs elements.

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