Analysis of flow field characteristics of pseudoplastic fluid mixing based on lattice Boltzmann method

Pseudoplastic fluid mixing is essential for homogenization in chemical industrial processes. This study validates a lattice Boltzmann method program and investigates the effects of impeller speed and rheological parameters on mixing flow fields. Results indicate that the consistency coefficient has limited influence, mainly confined to high-shear zones near the impeller. In contrast, reducing the flow index from 0.52 to 0.10 induces significant spatial heterogeneity: shear rate and velocity increase by up to 1.7 times and 0.035 times near the impeller, but decrease by 0.90 and 0.75 times in far-field regions, respectively. Increasing the initial yield stress markedly reduces the active mixing volume by 29.6%, severely impairing efficiency. While higher rotational speed enhances mixing via shear thinning, its effect saturates beyond a critical point. Similarly, in Newtonian fluids, flow stabilizes beyond a critical Reynolds number of 80. This study establishes quantitative relationships among rheological parameters, operational conditions, and mixing efficiency, providing a theoretical basis for process optimization.