Numerical insights into the interaction between carbon fibers and shear-thinning non-Newtonian fluids

The interaction between cylindrical particles and shear-thinning non-Newtonian fluids in uniform flow conditions is examined using particle-resolved direct numerical simulation (PR-DNS). The rheological properties of the fluid are characterized using the Carreau model. The effects of Reynolds number ( Re ), aspect ratio ( Ar ), power-law index ( n ), Carreau number ( Cu ), and inclination angle ( α ) on the drag coefficient ( C D ), lift coefficient ( C L ), and torque coefficient ( C T ) of cylindrical particles are systematically analyzed. The results show that shear-thinning properties effect the viscosity and pressure distribution, and also alter the flow field structure. With increasing shear-thinning properties, the effective viscosity near the particle surface is reduced, resulting in lower C D , C L , and C T . C D , C L , and C T decrease with increasing Re , and the effect of shear-thinning properties is more significant at low Re . Large Ar particles typically have larger C D , C L , and C T . In addition, the predictive correlations of C D , C L , and C T are developed based on the influence of the aforementioned factors. These findings and predictive correlations offer valuable insights for predicting and regulating the orientation and spatial distribution of cylindrical particles and provide guidance for the design and optimization of related industrial processes.