Enhancement of liquid–liquid micromixing performance in curved capillary microreactor by generation of Dean vortices

• Curved capillary microreactors generate Dean vortices that significantly enhance liquid–liquid micromixing, especially at low Reynolds numbers (Re < 30). • The minimum segregation index XS achieved was 0.008 under optimal conditions, indicating near-perfect micromixing. • Changing the curved shape reduced XS by 37.5% at low Re, demonstrating a simple and cost-effective intensification strategy. • New correlations between XS and Reynolds/Dean numbers were developed, enabling prediction of micromixing performance in capillary microreactors.