Structure optimization of plough blades in a ploughshare mixer using the DEM simulations

摘要

PurposeThe purpose of this paper is to optimize the structure of plough blades in a ploughshare mixer using the discrete element method (DEM) simulations.Design/methodology/approachUsing the validated DEM model, three numerical tests are conducted to determine how the mixing performance evolves as structural parameters of blades change. Results from the analysis provide basis for structure optimization of blades. The structural parameters include sweep angle of blade gamma, regular axial pitch p and regular circumferential angular offset alpha. The parameters to evaluate mixing performance include mass flow rate and Lacey index.FindingsThe DEM results show that the mixing performance at gamma of 35 degrees is better than 15 degrees, 25 degrees and 45 degrees. The mixer which has a p of less than or equal to 1.11 center dot b is more efficient than the mixer which has a p greater than 1.11 center dot b, where b is tail width of blade. The circumferential symmetric distribution of blades (alpha = 180 degrees) is more beneficial to improve the mixing performance in comparison with the circumferential asymmetric distribution (alpha 180 degrees). Based on the results, an optimized mixer with a gamma of 35 degrees, a p of 0.61 center dot b and an alpha of 180 degrees is proposed, which has a better mixing performance compared to all mixers listed.Originality/valueThe structural parameters of blades, including gamma, p and alpha, are found to be critical for good mixing. From the view angle of structure optimization of plough blades, a new ploughshare mixer with a gamma of 35 degrees, a p of 0.61 center dot b and an alpha of 180 degrees is investigated and recommended for improving mixing efficiency.