Flow simulation in a 2D bubble column with the Euler-Lagrange and Euler-Euler method

TL;DR

This study compares Euler-Lagrange and Euler-Euler simulation methods for 2D bubble columns, demonstrating that EL is more efficient up to a bubble count of around 40,000, with results aligning well with experimental data.

Contribution

It provides a detailed comparison of EL and EE methods in bubble column CFD simulations, highlighting the efficiency and accuracy trade-offs and estimating the critical bubble number where EE becomes preferable.

Findings

EL approach scales linearly with bubble number

EL is faster for up to 40,000 bubbles

Simulation results agree with experimental data

Abstract

Bubbly flows, as present in bubble column reactors, can be simulated using a variety of simulation techniques. In order to gain high resolution CFD methods are used to simulate a pseudo 2D bubble column using EL and EE techniques. The forces on bubble dynamics are solved within open access software OpenFOAM with bubble interactions computed via Monte Carlo methods. The estimated bubble size distribution and the predicted hold-up are compared to experimental data and other simulative work using EE approach and show reasonable consensus for both. Benchmarks with state of the art EE simulations shows that the EL approach is advantageous if the bubble number stays at a certain level, as the EL approach scales linearly with the number of bubbles simulated. Therefore, different computational meshes have been used to also account for influence of the resolution quality. The EL approach indicated faster solution for all realistic cases, only deliberate decrease of coalescence rates could push CPU time to the limits. Critical bubble number - when EE becomes advantageous over the EL approach - was estimated to be 40.000 in this particular case.