Spiral micromixers are one of the most widely used passive micromixers, but their mixing efficiency in the medium Reynolds number range (0.5∼50) is not ideal. To enhance the mixing efficiency of variable-radius spiral micromixers, VSR-C,VSR-T,VSR-H micromixers were designed by inserting cylindrical,triangular and hexagonal obstacles into the microchannel, and VSE, VST micromixers were designed by turning the cross section of the microchannel into triangle and ellipse. All micromixers were fabricated by LCD 3D printing. Simulation analysis and mixing experiments indicate that variable-radius spiral micromixers with obstacles can only increase mixing efficiency at high Reynolds number, while micromixers with triangular or elliptical cross sections can improve the mixing efficiency not only at high Reynolds number (Re > 5), but also at low and medium Reynolds number (Re < 3). The results suggest more Dean vortexes could be generated in spiral micromixer with an elliptical cross section (VSE) at the same Dean number,and the effective action area of Dean flow is enlarged simultaneously. As compared to VSR micromixer, the mixing efficiency of VSE exhibited 28% improvement on average, which implys the optimization of cross-section shape provides a potential way to improve the performance of spiral micromixers.

螺旋微混合器是应用最广泛的被动微混合器之一，但其在中等雷诺数范围（0.5∼50）内的混合效率并不理想。为提高变半径螺旋微混合器的混合效率，通过在微通道中插入圆柱形、三角形和六边形障碍物设计了VSR-C、VSR-T、VSR-H微混合器，并通过改变横截面设计了VSE、VST微混合器微通道分为三角形和椭圆形。所有微混合器均通过 LCD 3D 打印制造。仿真分析和混合实验表明，带障碍物的变半径螺旋微混合器只能在高雷诺数下提高混合效率，而三角形或椭圆形横截面的微混合器不仅可以在高雷诺数下提高混合效率（Re > 5)，但也在低和中雷诺数 ( Re  < 3) 下。结果表明，在相同的迪安数下，椭圆截面（VSE）螺旋微混合器可以产生更多的迪安涡流，同时扩大了迪安流的有效作用面积。与 VSR 微混合器相比，VSE 的混合效率平均提高了 28%，这意味着横截面形状的优化为提高螺旋微混合器的性能提供了潜在的途径。