Topology Optimization Of Passive Micromixer Channels

Micromixer, which achieves the efficient mixing of reagents, is an important functional part of the microfluidic chips. In the area of biologic reaction, such as chemical analysis, genic analysis and albuminoid analysis, micromixer can help to perform a fast and efficient biologic reaction. However, the design of micro-mixer was mainly based on test-and-error method. A systematical design procedure was first proposed by Andresen et al. in 2008 based on topology optimization method. In this thesis, the effect of design domain and manufacturing constraint which influence the efficiency of mixing is discussed based on work by Andresen et al. A micro-mixer with deep design domain and long space between two block units is proposed. Based on the continuous impressible Navier-Stokes equation and the convection-diffusion equation, the finite element method is used to simulate the mixing problem. For the design of the micromixer, the optimization model is constructed, and the optimization model is analyzed by the GLS and Petrov-Galerkin/Compensated stabilized method. By the adjoint analysis method, the adjoint sensitivity of the optimization model is obtained. The cubic mesh (3D) are used for the discritization of the problem. When the pressure drop between the inlet and outlet of the fluidic channel is set as constraint in the optimization model, the optimized results can at most improve the effect of mixing about three times when compared with a empty pipe with the same length of micro channel. For different values ofβand manufacturing constraint, the influence of the constraint on the results are analyzed. At last, the experiments of the mixing is designed, and the mixing effect for the design micromixer has been verified by experiments.