【摘要】 电渗压力混合流已广泛应用于各种生化微流控领域中，其中黏弹性流体的弹性不稳定性不可忽视.采用黏弹性流体，对10∶1∶10的微通道缩放管中电渗压力混合驱动流动进行数值仿真.研究了不同压力和不同聚合物浓度对流体流动的影响，并分析了Newton流体与黏弹性流体在缩放管中速度分布的叠加原理.结果表明：反向压力使黏弹性流体展现出更大的不稳定性，使得入口涡流变大，压力每增大1 Pa涡流变大25μm,而正向压力使涡流变小.较小反向压力时，入口涡流随着聚合物浓度的增大而增大，并逐渐趋于稳定.在较大反向压力下，涡流大小随着聚合物浓度的增大先升后降.更多还原

【Abstract】 The electroosmotic and pressure-driven mixed flow was widely used in various biochemical microfluidic fields, where the elastic instability of the viscoelastic fluid cannot be ignored. A viscoelastic fluid was used to numerically simulate electroosmotic and pressure-driven mixed flow in a 10∶1∶10 microchannel converging-diverging tube. The effects of different pressures and different polymer concentrations on the fluid flow were studied, and the superposition principle for the velocity distributions of Newtonian fluids and viscoelastic fluids in converging-diverging tubes was analyzed. The results show that, the reverse pressure brings the viscoelastic fluid into higher instability, which makes the inlet vortex larger by 25 μm for every 1 Pa pressure increase. The positive pressure makes the eddy current smaller. For a relatively small reverse pressure, the inlet vortex increases with the polymer concentration and tends to be stable gradually. For a relatively large reverse pressure, the vortex size first increases and then decreases with the polymer concentration.更多还原