Flow Regimes and Mixing of Dissimilar Fluids in T‐Jets Mixers

• Published in: Chemical engineering & technology 2022-02, Vol.45 (2), p.355-364
• Main Authors: Brito, Margarida S. C. A., Fonte, Cláudio P., Dias, Madalena M., Lopes, José Carlos B., Santos, Ricardo J.
• Format: Article
• Language: English
• Subjects: Computational fluid dynamics; Dissimilar fluids; Fluid flow; Fluorescence; Impingement; Jets; Kinetic energy; Laminar flow; Mixers; Mixing; Reynolds number; T‐jets mixer; Viscosity ratio; Viscous fluids
• ISSN: 0930-7516; 1521-4125
• DOI: 10.1002/ceat.202100536

Efficient mixing conditions for similar fluids in T‐Jets mixers are well‐established. This paper extends the characterization of the mixing of dissimilar fluids. Planar laser‐induced fluorescence images were captured using fluids with a viscosity ratio between 1.2 and 3. Flow visualizations showed that the best mixing conditions are achieved when the jets are well‐balanced, and the onset of a chaotic flow regime is determined by the Reynolds number of the more viscous fluid (ReHjet > 100). Computational fluid dynamics simulations were also performed to get deeper insight into the flow field and mixing dynamics, enabling the prediction of the impingement point position. An analytical model based on jets' kinetic energy rate balance is proposed as a design tool to predict the impingement point position. Chaotic flow regime in T‐Jets mixers can engulf the mixing of fluids with different viscosities. The Reynolds number of the more viscous fluid must be above 100, and both jets must be well‐balanced. A new analytical model based on kinetic energy rate balance is proposed to predict the impingement point position in T‐jets mixers. This model was validated from computational fluid dynamics simulations.