# Investigation of the force closure for Eulerian-Eulerian simulations: a validation study of nine gas-liquid flow cases

## TL;DR

This study evaluates the impact of different force models in Eulerian-Eulerian gas-liquid flow simulations, identifying key forces necessary for accurate predictions across various industrial applications and validating results against experimental data.

## Contribution

It provides a comprehensive validation of force closure models in Eulerian-Eulerian simulations for diverse industrial bubbly flows, establishing guidelines for numerical settings.

## Key findings

- Drag and turbulent dispersion forces are essential for accurate predictions.
- Lift and wall lubrication forces are important near walls, especially in pipe flows.
- Neglecting lateral forces is acceptable in some flow configurations.

## Abstract

Gas-liquid flows can be simulated by the Eulerian-Eulerian (E-E) method. Whether to include a specific momentum interfacial exchange force model remains as a question with no answer. In this work, our aim is to seek a general numerical settings for the E-E method, which can provide competent results for industrial bubbly flows with different geometries under different operations. They were selected from different industries including chemical, nuclear, bio-processing and metallurgical engineering. Simulations were launched by the OpenFOAM solver reactingTwoPhaseEulerFoam, in which the E-E method was implemented with sophisticated numerical techniques to ensure stabilities. Predictions were compared against experimental data. It was found that the drag force and turbulent dispersion force play the most important role on the predictions and should be included for all simulations. The first one accounts for the two-way coupling while the second one accounts for the turbulence effect and ensures the E-E equations to be well-posed. The lift force and wall lubrication force should be included to address the phase fraction accumulation in the vicinity of the wall, especially for pipe flows with large aspect ratio. In other cases the lateral forces can be safely neglected. All the test case are open-sourced and are available as supplementary data for anyone to download as baseline test cases.