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Updated: Jun 26, 2025

Glass-Based Devices to Generate Drops and Emulsions
Published on: April 5, 2022
Auto-ejection of liquid from a nozzle
Fang Shan1, Zhenhua Chai1,2,3, Baochang Shi1,2,3
1School of Mathematics and Statistics, Huazhong University of Science and Technology, Wuhan 430074, China.
Abstract:
Auto-ejection of liquid is an important process in engineering applications, and is also very complicated since it involves interface moving, deforming, and jet breaking up. In this work, a theoretical velocity of meniscus at nozzle exit is first derived, which can be used to analyze the critical condition for auto-ejection of liquid. Then a consistent and conservative axisymmetric lattice Boltzmann (LB) method is proposed to study the auto-ejection process of liquid jet from a nozzle. We test the LB model by conducting some simulations, and find that the numerical results agree well with the theoretical and experimental data. We further consider the effects of contraction ratio, length ratio, contact angle, and nozzle structure on the auto-ejection, and observe some distinct phenomena during the ejection process, including the deformation of meniscus, capillary necking, and droplet pinch off. Finally, the results reported in the present work may play an instructive role on the design of droplet ejectors and the understanding of jetting dynamics in microgravity environment.
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