Enhanced axial mixing of rotating drums with alternately arranged baffles

•The mixing performance of alternately arranged baffles is evaluated via GPU-based DEM simulations.•This novel arrangement of baffles displays higher axial mixing efficiency.•Optimum baffle dimensions and number are obtained.•The mechanisms of enhanced axial mixing are ascribed to the scattering effect and guiding effect.•Potential applications of this design in industrial mixers are fully examined.

Traditional rotating drums are a popular type of tumbling mixer; however, they generally suffer from poor axial mixing with granular materials. To overcome this weakness, a system of alternately arranged baffles is presented, and its effect on particle mixing is numerically assessed using a GPU-based discrete element method. It is found that this arrangement of baffles displays better axial mixing performance than drums with (or without) traditional baffles, and that maximum mixing efficiency can be obtained through a suitable choice of baffle dimension and number. Essentially, this novel arrangement promotes the bulk movement of particles in the axial direction because of the combined radial scattering and axial guiding effects of the baffles. Together with the enhanced dispersive mixing, axial convective mixing serves to increase the axial mixing efficiency. Moreover, it is found that alternately arranged baffles produce good performance in various granular systems of rotating drums. Thus, the proposed system is a promising approach for industrial applications in more complicated mixers.

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