By using the multi-phase field method for interface-capturing simulations of gas-liquid interface motion, it became possible to analyze bubbly flows that were difficult to treat with conventional methods. In the analysis of bubble flows in a circular pipe, comparison of the radial void fraction and the mean velocity distribution (Water: liquid, Bubble: gas) with experimental results confirmed that the present simulation provides reasonable predictions.

In this study, we propose a novel computational method for gas-liquid two-phase flows (mixtures of water and air) to address the issue of bubbles artificially coalescing in numerical simulations. In conventional simulation approaches, bubbles tend to “stick together” when they come into proximity, leading to flow behaviors that deviate from experimental observations. To overcome this, we employ the Multi-Phase Field (MPF) method, in which an independent phase function is assigned to each bubble, thereby preventing spurious numerical coalescence.

Furthermore, to reduce the computational cost of handling information for hundreds of bubbles, we introduce an efficiency-enhancing technique called Ordered Active Parameter Tracking (OAPT). This approach significantly decreases memory usage and computation time, enabling the simulation of large-scale bubbly flows.

To validate the proposed method, we performed simulations of turbulent bubbly flow in a vertical pipe and compared the results with the experimental data of Colin et al. The predicted bubble distributions and velocity profiles showed good agreement with the measurements.

In summary, this work realizes a “non-coalescing bubble simulation” that preserves bubble identity and achieves high-fidelity flow analysis consistent with experiments. These results are expected to contribute to the prediction of complex bubbly flows in various fields, including nuclear engineering, chemical processing, and space applications.

This research was supported by JSPS KAKENHI, Grant-in-Aid for Scientific Research (C) (JP24K14973), and Joint Usage/Research Center for Interdisciplinary Large-Scale Information Infrastructures (JHPCN) in Japan (Project ID: jh240071).

Sugihara, K. et al., Bubble Flow Analysis Using Multi-Phase Field Method, EPJ Web of Conferences, Paris, France, vol.302, 2024, 03002, 10p.

Paper URL: https://doi.org/10.1051/epjconf/202430203002

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