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

A novel electroosmotic microdevice for efficient micromixing in biodiesel synthesis

Pei-Ying Su, Fu-Chiang Yang, Ming-Hung Shu, and Jui-Chan Huang

Department of Industrial Engineering and Management, National Kaohsiung University of Science and Technology, Kaohsiung City, Taiwan

E-mail: hjc0718@nkust.edu.tw

Received: 4 October 2025  Accepted: 22 October 2025

Abstract:

This study introduces a novel three-dimensional electroosmotic micromixer featuring a curved section, a short divergent connector, and a straight mixing region equipped with three pairs of opposite electrodes. Numerical simulations based on finite element analysis are performed to evaluate the mixing index (MI), pressure drop (Δp), and concentration fields under both AC and DC electric field actuations. Results demonstrate that DC-driven MI strongly increases with applied voltage at low Reynolds numbers (Re), achieving nearly complete mixing. For AC operation, both the frequency and voltage significantly affect the time-dependent evolution of MI: lower frequencies (4 Hz) and higher voltages yield pronounced and sustained mixing improvements due to robust electroosmotic vortex generation, as opposed to higher frequencies (27 Hz), where weaker vortex activity limited mixing. The curved–divergent–straight hybrid design promotes efficient interfacial area expansion, synergistically combining Dean and electroosmotic vortices for rapid and uniform mixing.

Keywords: Microfluidics; Electroosmotic micromixer; Oil; Ethanol; Biodiesel

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-025-04474-x

Chemical Papers 80 (2) 1613–1626 (2026)