An optimised split-and-recombine micro-mixer with uniform ‘chaotic’ mixing

TLDR

The authors present a second‑generation micro‑mixer optimized with a split‑and‑recombine principle. They evaluate the mixer’s performance using CFD across Reynolds numbers 1–100 and validate the results experimentally with water‑glycerol solutions. The mixer exhibits a positive finite‑time Lyapunov exponent, near‑ideal multi‑lamination at Re < 15, and high mixing efficiency for viscous fluids, as confirmed by experiments.

Abstract

A second generation micro-mixer, being a further optimised version of a first prototype, relying on the consequent utilisation of the split-and-recombine principle is presented. We show that the mixing can be characterized by a positive finite-time Lyapunov exponent although being highly regular and uniform. Using computational fluid dynamics (CFD) we investigate the mixing performance for Reynolds numbers in the range of about 1 to about 100. In particular for low Reynolds numbers (Re < 15) the CFD results predict an almost ideal multi-lamination. Thus, the developed mixer is especially suited for efficient mixing of highly viscous fluids. Furthermore, the numerical results are experimentally validated by investigations of mixing of water-glycerol solutions. The experimental results are found to be in excellent agreement with the numerical data and prove the high mixing efficiency.