Two-Phase Flow Dynamics and Mass Transfer Mechanisms

Two-phase flow systems, in which two immiscible fluids interact, underpin numerous industrial and environmental processes ranging from chemical reactors and heat exchangers to natural phenomena such as bubble plumes in the ocean. The dynamics of these systems are governed by the interplay of hydrodynamic forces, interfacial tension and turbulent fluctuations, which together determine the formation, deformation, coalescence and breakup of dispersed elements. Mass transfer across the interface is intrinsically linked to the available interfacial area and the local flow conditions, with turbulence enhancing mixing yet also driving fragmentation that can either promote or inhibit transport. Advances in experimental diagnostics, computational fluid dynamics and data‐driven methods have deepened our understanding of the mechanisms that control phase distribution, interfacial morphology and scalar transport. The global significance of this research is evident in the optimisation of energy systems, improved reactor designs and more accurate models of natural mixing processes.

Research from Nature Portfolio

Recent studies have introduced deep-learning approaches to automate the detection and characterisation of bubbles in gas–liquid flows. By training convolutional neural networks on diverse bubble images, these methods achieve high accuracy across varying bubble sizes and flow regimes, dramatically reducing manual calibration and accelerating image‐based interfacial area measurements. Another investigation has revisited the century-old Kolmogorov-Hinze paradigm for drop and bubble breakup, demonstrating experimentally that sub-bubble-scale turbulent eddies play a dominant role in fragmentation. This work shows that breakup cannot be predicted solely by classical stress criteria but requires accounting for local deformation timescales, offering a refined framework for predicting droplet and bubble size distributions in turbulent flows.

Two-Phase Flow Dynamics and Mass Transfer Mechanisms publication trend

The graph below shows the total number of articles in two-phase flow dynamics and mass transfer mechanisms across all publications each year (not limited to Nature Index journals).

Technical terms

Two-phase flow: Simultaneous flow of two distinct phases (e.g. gas–liquid) with relative motion and interfacial interaction.

Mass transfer: Movement of chemical species across phase boundaries driven by concentration or chemical potential differences.

Interfacial tension: Force per unit length existing at the boundary between two immiscible fluids, influencing deformation and stability.

Weber number: Dimensionless ratio of inertial forces to interfacial tension forces, critical to predicting breakup behaviour.

Hinze scale: Critical droplet or bubble diameter above which turbulent stresses typically overcome interfacial forces, leading to fragmentation.

References

1. Deep learning-based automated and universal bubble detection and mask extraction in complex two-phase flows. Scientific Reports (2021).
2. Fragmentation in turbulence by small eddies. Nature Communications (2022).
3. Two-Phase Bubble Columns: A Comprehensive Review. ChemEngineering (2018).
4. Direct numerical simulation of bubble-induced turbulence. Journal of Fluid Mechanics (2021).
5. Droplets in homogeneous shear turbulence. Journal of Fluid Mechanics (2019).