ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Acoustic streaming impact on micromixing of a novel microfluidic device

Hongwei Wu, Lanlan Sun, Qian Cheng, and Qiang Zhu

Anqing Petrochemical Third Primary School, Anqing, China

E-mail: zhuqiang810906@163.com

Received: 25 November 2025  Accepted: 14 December 2025

Abstract:

In microfluidic systems, achieving rapid and efficient mixing remains a significant challenge due to the prevalence of laminar flow and diffusion-limited transport. Acoustic streaming generated by sharp-edge structures has emerged as a promising active mixing technique. This study introduces a novel acoustic micromixer featuring a strategically engineered mixing chamber with integrated sharp-edge structures, distinctly characterized by its widened central mixing zone (Geometry 2), compared to a standard straight-channel design (Geometry 1). Actuated by a piezoelectric transducer (PZT), the device leverages localized acoustic streaming vortices for enhanced mixing efficiency (ME). This paper systematically deconvolutes the effects of the sharp-edge angle (θ) and the inter-edge distance (b) on vortex formation and mixing performance. The results establish that acute sharp-edge angles (θ = 45°) and minimal spacing (b = 400 µm) are paramount for generating powerful, constructive streaming flows. The optimized Geometry 2 achieves a near-perfect ME of 96.4%, with a uniform outlet concentration profile of 0.5 ± 0.01, significantly outperforming the 55% efficiency observed for obtuse angles (θ = 180°) and larger distances (b = 800 µm). Crucially, the innovative chamber design of Geometry 2 demonstrates superior performance over the conventional Geometry 1 under identical actuation conditions, highlighting the advantage of the widened mixing zone. This performance (ME > 96%) compares favorably with the state-of-the-art in sharp-edge acoustic mixers, which typically report efficiencies in the range of 90–95% for similar mixing lengths. The present findings provide definitive, quantitative design guidelines, proving that the synergistic optimization of both the sharp-edge geometry and the global chamber architecture is essential to unlock the full potential of acoustic streaming for overcoming diffusion-limited mixing in microfluidic applications.

Keywords: Microfluidic device; Micromixer; Mixing efficiency; Sharp-edge structures; Acoustic streaming

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-025-04599-z

Chemical Papers 80 (5) 4913–4927 (2026)