Accurate calculation of bubble and droplet properties in diffuse-interface two-phase simulations

TL;DR

This paper introduces a simple volume-correction method for diffuse-interface two-phase flow simulations that accurately calculates droplet and bubble properties, overcoming limitations of flood-fill algorithms and arbitrary volume fraction cutoffs.

Contribution

A novel volume-correction approach that analytically approximates truncated volumes, improving accuracy in droplet and bubble property calculations in diffuse-interface simulations.

Findings

Accurately recovers dispersed phase volumes with minimal error.

Works effectively over a wide range of volume fraction cutoffs.

Enables precise size distribution analysis and multi-scale modeling.

Abstract

In this paper, we address the challenge of accurately calculating droplet/bubble properties (e.g., volume, number) in diffuse-interface two-phase flow simulations. Currently, flood-fill algorithms can truncate a significant portion of the volume of droplets/bubbles contained within the diffuse interface region or artificially merge multiple droplets/bubbles. This error is also dependent on the volume fraction cutoff value, which is typically chosen to be 0.5 arbitrarily, in the flood-fill algorithms. We propose a simple volume-correction approach that incorporates an analytical approximation of the truncated volume to correct for the missing droplet/bubble volumes. This proposed method results in accurately recovering the dispersed phase volumes with minimal volume error over a wide range of volume fraction cutoff values; and hence, can also accurately recover the number of droplets/bubbles. This can be a valuable tool for accurate calculation of drop/bubble size distributions for analysis and for Eulerian-to-Lagrangian conversion of the dispersed phase in multi-scale modeling approaches.