Computations of breakup modes in laminar compound liquid jets in a coflowing fluid
| Autor: | Truong V. Vu, Hideyuki Takakura, John C. Wells, Shunji Homma, Gretar Tryggvason |
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| Rok vydání: | 2013 |
| Předmět: |
Fluid Flow and Transfer Processes
Materials science Astrophysics::High Energy Astrophysical Phenomena Mechanical Engineering Drop (liquid) Nuclear Theory General Physics and Astronomy Reynolds number Laminar flow Mechanics Breakup Physics::Fluid Dynamics Surface tension symbols.namesake Classical mechanics Compressibility Newtonian fluid symbols Weber number High Energy Physics::Experiment |
| Zdroj: | International Journal of Multiphase Flow. 49:58-69 |
| ISSN: | 0301-9322 |
| Popis: | We present a numerical investigation of breakup modes of an axisymmetric, laminar compound jet of immiscible fluids, which flows in a coflowing immiscible outer fluid. We use a front-tracking/finite difference method to track the unsteady evolution and breakup of the compound jet, which is governed by the Navier–Stokes equations for incompressible Newtonian fluids. Numerical results show that depending on parameters such as the Reynolds number Re (in the range of 5–30) and Weber Number We (in the range of 0.1–0.7), based on the inner jet radius and inner fluid properties, the compound jet can break up into drops in various modes: inner dripping–outer dripping (dripping), inner jetting–outer jetting (jetting), and mixed dripping–jetting. Decreasing Re or increasing We promotes the jetting mode. The transition from dripping to jetting is also strongly affected by the velocity ratios, U 21 (intermediate to inner velocities) and U 31 (outer to inner velocities). Increasing U 21 makes the inner jet thinner and stretches the outer jet and thus promotes jetting. In contrast, increasing U 31 thins the outer jet, and thus, when the inner jet is dripping, the outer jet can break up into drops in the mixed dripping–jetting mode. Continuously increasing U 31 results in thinning both inner and outer jets and thus produces small drops in the jetting mode. In addition, starting from dripping, a decrease in the interfacial tension ratio of the outer to inner interfaces results in the mixed dripping–jetting and jetting modes. These modes produce various types of drops: simple drops, and compound drops with a single inner drop (single-core compound drops) or a few inner drops (multi-core compound drops). |
| Databáze: | OpenAIRE |
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