高回流被动式微混合器设计及数值模拟

为了提高混合强度设计了一种高回流被动式微混合器，其反馈通道中的回流延长了混合时间并促进形成涡流，增强了对流和扩散作用。通过优化反馈通道形状和混合腔入口尺寸，该微混合器提升了其回流率和混合强度。利用仿真软件Fluent分析该微混合器的性能，仿真表明对于给定的微混合器其回流率和混合强度仅仅决定于雷诺数，回流率和混合强度均随雷诺数增大而增大。特别地，当雷诺数低至8.3时，仍可在反馈通道中找到回流；当雷诺数为99.6时，回流率达到24%，混合强度则超过60%。通过对反馈通道倾斜角度参数的模拟，该微混合器的回流率和混合强度均有明显提升。

Design and numerical simulation of a high reflux passive micromixer

A novel reflux passive micromixer with high reflux rate is proposed to improve the mixing index. The refluxes in its feedback channels lead to a longer mixing time and improve the formation of the vortexes, which then strengthen the diffusion and convection in the micromixer. The reflux rate and the mixing index of the micromixer are improved by optimizing the shape of two feedback channels and the inlet size of the mixing chamber. The performance of the proposed micromixer is examined by using the simulation software Fluent. Simulation results indicate that the reflux rate and the mixing index are only dependent on the Reynolds number for a specified micromixer. The reflux rate and the mixing index will both be improved by increasing the Reynolds number. Based on the observations with different angle parameters, a reasonable choice of the angel to achieve satisfied reflux rate and the mixing index is 10°. In this scenario, refluxes still exist in the feedback channels when the Reynolds number is only 8.3. When the Reynolds number is 99.6, the reflux rate reaches 24% and the mixing index is over 60%.