Effects of viscosity and shear-thinning characteristics of a liquid jet in air crossflow
Yasuhiro Saito, Kento Mukai, Shota Nakashima, Shuichi Iwata, Minori Shirota, Yohsuke Matsushita
Abstract
• The penetration height increased with a decrease in apparent viscosity. • The outer liquid jet of a shear-thinning fluid affected the liquid behavior. • The bending and breakup energies were distinguished. • The bending energy increased linearly with increasing viscosity. • The breakup energy showed a nonlinear rise, indicating complex fluid behavior. In the present study, we performed numerical simulations of a single liquid jet with varying viscosities and non-Newtonian characteristics in uniform gas crossflows at different velocities, to investigate the effects of liquid properties on jet deformation and breakup behavior. By utilizing air as the gas and examining both Newtonian fluids with different viscosities and a shear-thinning fluid as the liquid, we aimed to uncover the intricate dynamics governing liquid jet deformation and breakup under crossflow conditions. At lower air velocities, the liquid jet bent and elongated without undergoing breakup, regardless of the viscosity and shear-thinning characteristics. Notably, in the case of the shear-thinning fluid, the effect of the viscosity was more pronounced in the outer regions of the liquid jet than at its center. In contrast, at higher air velocities, viscosity and shear-thinning characteristics significantly affected jet breakup; the high-viscosity Newtonian liquid jet resisted breakup, while the low-viscosity jet broke up into threads, with a decrease in apparent viscosity leading to increased penetration height. This study introduces a novel method for quantifying the energy transfer from gas to liquid jet, using pressure differences between a deformable liquid jet and an equivalent rigid cylinder as a reference. This approach allows for the separation of bending and breakup energy components, offering new quantitative insights into the forces driving jet deformation and breakup. These insights advance the current understanding of fluid-structure interactions in crossflow conditions.