Direct-current electrospray dynamics in power-law non-Newtonian fluids

To improve process control in microscale and nanoscale manufacturing of complex materials and precision regulation in emerging sustainable energy systems, this work numerically simulates the cone-jet electrospray formation process of power-law fluids. The results show that the power-law index has a monotonic effect on Taylor cone morphology, the internal flow field, charge transport, and droplet breakup. As the power-law index (n) increases, both the dimensionless cone length and the cone angle increase. In particular, shear-thinning fluids (n < 1) tend to form compact, short, and sharp menisci. The abrupt decrease in viscosity at the cone tip increases the cone-jet velocity and convective current, promoting multistage instability breakup with satellite droplets. By contrast, shear-thickening fluids (n > 1) form elongated, thick menisci because of strong viscous resistance. Axial jet motion is suppressed, the convective current decreases, and conduction-dominated charge accumulation increases the surface charge density, leading to delayed breakup and spindle-like droplets. The findings provide guidance for electrospray control and process optimization of complex working fluids.