Direct numerical simulation of water-ethanol flows in a T-mixer

TL;DR

This paper presents a high-fidelity numerical simulation method for water-ethanol flows in a T-mixer, exploring turbulence transition and mixing dynamics across different flow regimes, which enhances understanding of complex fluid interactions.

Contribution

The study introduces an accurate numerical approach for simulating two-fluid mixtures, specifically water-ethanol, in turbulent regimes within T-mixers, filling a gap in existing research.

Findings

Flow states during turbulence transition are characterized.

Mixing properties of water-ethanol are analyzed and compared to water-water mixtures.

Simulation results provide detailed insights into flow dynamics at various Reynolds numbers.

Abstract

The efficient mixing of fluids is key in many applications, such as chemical reactions and nanoparticle precipitation. Detailed experimental measurements of the mixing dynamics are however difficult to obtain, and so predictive numerical tools are helpful in designing and optimizing many processes. If two different fluids are considered, the viscosity and density of the mixture depend often nonlinearly on the composition, which makes the modeling of the mixing process particularly challenging. Hence water-water mixtures in simple geometries such as T-mixers have been intensively investigated, but little is known about the dynamics of more complex mixtures, especially in the turbulent regime. We here present a numerical method allowing the accurate simulation of two-fluid mixtures. Using a high-performance implementation of this method we perform direct numerical simulations resolving the spatial and temporal dynamics of water-ethanol flows for Reynolds numbers from 100 to 2000. The flows states encountered during turbulence transition and their mixing properties are discussed in detail and compared to water-water mixtures.