Effect of geometry ratios on droplet breakup in a T-junction microchannel: A theoretical predictive model

doi:10.1016/j.cjche.2025.07.005

Abstract

Abstract: Understanding and predicting droplet breakup is essential in droplet-based microfluidic systems, as it enables precise control over droplet manipulation for various applications. In this study, droplet breakup behavior in a T-junction microchannel is investigated under the influence of microchannel geometry using three-dimensional numerical simulations. A theoretical model is developed based on the balance between surface tension and viscous drag forces acting on the droplet, incorporating the effects of geometric parameters on droplet length. This model predicts the critical Capillary number required for breakup to occur. The theoretical predictions are validated using both previous research data and the present numerical simulations. The results show that the model accurately predicts the transition between breakup and non-breakup regimes. Specifically, an increase in sidearm length ratio inhibits droplet breakup and leads to an asymmetric breakup regime. Furthermore, increasing the outlet-to-inlet width ratio also reduces the likelihood of droplet breakup. These findings provide a predictive framework for understanding and controlling droplet dynamics in microfluidic T-junctions, with potential applications in lab-on-a-chip technologies.

Key words: T-junction, Sidearm length, Capillary number, Breakup, Width ratio, Theoretical predictive model

摘要： Understanding and predicting droplet breakup is essential in droplet-based microfluidic systems, as it enables precise control over droplet manipulation for various applications. In this study, droplet breakup behavior in a T-junction microchannel is investigated under the influence of microchannel geometry using three-dimensional numerical simulations. A theoretical model is developed based on the balance between surface tension and viscous drag forces acting on the droplet, incorporating the effects of geometric parameters on droplet length. This model predicts the critical Capillary number required for breakup to occur. The theoretical predictions are validated using both previous research data and the present numerical simulations. The results show that the model accurately predicts the transition between breakup and non-breakup regimes. Specifically, an increase in sidearm length ratio inhibits droplet breakup and leads to an asymmetric breakup regime. Furthermore, increasing the outlet-to-inlet width ratio also reduces the likelihood of droplet breakup. These findings provide a predictive framework for understanding and controlling droplet dynamics in microfluidic T-junctions, with potential applications in lab-on-a-chip technologies.

关键词: T-junction, Sidearm length, Capillary number, Breakup, Width ratio, Theoretical predictive model

Thanh Tung Nguyen, Van Thanh Hoang. Effect of geometry ratios on droplet breakup in a T-junction microchannel: A theoretical predictive model[J]. Chinese Journal of Chemical Engineering, 2025, 88(12): 13-20.

Thanh Tung Nguyen, Van Thanh Hoang. Effect of geometry ratios on droplet breakup in a T-junction microchannel: A theoretical predictive model[J]. 中国化学工程学报, 2025, 88(12): 13-20.

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