To effectively control the mixing of target materials inside microfluidic devices, the Dean flow features of generalized-Newtonian Bird-Carreau (BC) fluids in curved rectangular channels are theoretically investigated, as a passive technique. Governing equations coupled with the Cauchy momentum equation and the BC model are solved using the finite volume scheme with a semi-implicit method for pressure-linked equations-revised (SIMPLER) algorithm. The effects of the rheological parameters of BC model, such as viscosity ratio, power-law index, and relaxation time constant, on the Dean flow are systematically examined in a wide range of Dean numbers (Dn), (very low to O(10²)). The entire flow characteristics of BC fluids in curved microchannels with increasing Dn are quantified using flow skewness, Dn_Ref/Dn_MES, and magnitude of vorticity, resulting in two main findings of a more outward-skewed streamwise velocity profile and a more enhanced secondary Dean vortex for non-Newtonian fluids in comparison to the Newtonian case at the same Dn.

中文翻译：

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弯曲微通道中非弹性Bird-Carreau流体的二次Dean流动特性

为了有效地控制目标材料在微流控设备中的混合，从理论上研究了广义牛顿伯德卡罗（BC）流体在弯曲矩形通道中的Dean流动特性，并将其作为一种被动技术。使用有限体积方案，通过半隐式方法对压力链接方程修正（SIMPLER）算法求解与Cauchy动量方程和BC模型耦合的控制方程。在广泛的Dean数（Dn）范围内（非常低至O（10），系统地研究了BC模型的流变参数（如粘度比，幂律指数和松弛时间常数）对Dean流动的影响。²））。随着Dn的增加，弯曲微通道中BC流体的整体流动特性通过使用流量偏度Dn _Ref / Dn _MES和涡度进行量化，得出两个主要发现：与非牛顿流体相比，非牛顿流体的偏斜流速度分布和次级Dean涡更增强。相同的Dn。