Chaotic advection and mass transfer of viscous liquid–liquid flows in a novel <scp>3D</scp> serpentine microchannel

Abstract This article aimed to study the characteristics of chaotic advection and mass transfer of viscous liquid–liquid flows in a novel 3D serpentine microchannel (TSM) with hybrid structures. The TSM and its corresponding experimental setup are established, and the CFD model is verified through flow field visualization experiments. Results reveal that efficient chaotic convection in TSM is achieved through continuous irregular spatial fluid deformation. The Lyapunov exponents greater than zero indicate the existence of chaotic behavior, and the maximum lineal stretch rate λ M increases linearly with the characteristic Reynolds number. The mass transfer characteristics are evaluated by diffusion mass transfer number Φ and mass transfer field synergy number Fc quantitatively. The mixing index MI shows an increasing trend as Fc increases, while the mixing effectiveness ME decreases as the outlet Reynolds number Re O decreases. The relationships of MI with λ M and Fc and the relationship of ME with Re O are established.