In the microfluidic systems, the structure of micromixer is one of the important influence factors for the mixing performance. The traditional trial-and-error method for the optimization design of micromixer structure is difficult to consider both the mixing performance and power dissipation. Here we show the topology optimization method of designing the passive micromixer with the minimum power dissipation. The micromixer structure is updated with the adjoint method and adjoint variables are solved by the continuous adjoint equation derived manually. The forward fluid problem and adjoint equation are constructed using OpenFOAM. The optimal structure of micromixer is generated at different mixing index constraint and Re in two-dimensional design problem. Furthermore, in the three-dimensional optimal design, the multiple spiral slice structures are produced along the micromixer, which generate chaotic advection. This open-source topology optimization modeling framework is effective to design optimal structure of micromixer.

在微流控系统中，微混合器的结构是影响混合性能的重要因素之一。微混合器结构优化设计的传统试错法难以兼顾混合性能和功耗。在这里，我们展示了设计具有最小功耗的无源微混频器的拓扑优化方法。使用伴随方法更新微混合器结构，并通过手动导出的连续伴随方程求解伴随变量。正向流体问题和伴随方程是使用 OpenFOAM 构建的。微混合器的最优结构是在不同的混合指标约束和Re在二维设计问题中。此外，在三维优化设计中，沿微混合器产生多个螺旋切片结构，产生混沌平流。这种开源拓扑优化建模框架对于设计微混合器的优化结构是有效的。