Microfluidic platforms have increasingly been explored for in vitro blood diagnostics and for studying complex microvascular processes. The perfusion of blood in such devices is typically achieved through pressure-driven setups. Surface tension driven blood flow provides an alternative flow delivery option, and various studies in the literature have examined the behavior of blood flow in such fluidic devices. In such flows, the influence of red blood cell (RBC) aggregation, the phenomenon majorly responsible for the non-Newtonian nature of blood, requires particular attention. In the present work, we examine differences in the surface tension driven flow of aggregating and non-aggregating RBC and Newtonian suspensions, in a rectangular microchannel. The velocity fields were obtained using micro-PIV techniques. The analytical solution for blood velocity in the channel is developed utilizing the power law model for blood viscosity. The results showed that RBC aggregation has an impact at the late stages of the flow, observed mainly in the bluntness of the velocity profiles. At the initial stages of the flow, the shearing conditions are found moderately elevated, preventing intense RBC aggregate formation. As the flow decelerates in the channel, RBC aggregation increases, affecting the flow characteristics.

中文翻译：

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矩形微流体通道中表面张力驱动的血液流动：红细胞聚集的影响

越来越多地探索微流体平台用于体外血液诊断和研究复杂的微血管过程。这种设备中的血液灌注通常是通过压力驱动的设置来实现的。表面张力驱动的血流提供了另一种流量输送选项，文献中的各种研究已经检查了此类流体装置中血流的行为。在这种流动中，需要特别注意红细胞 (RBC) 聚集的影响，这种现象是血液的非牛顿性质的主要原因。在目前的工作中，我们研究了在矩形微通道中聚集和非聚集 RBC 和牛顿悬浮液的表面张力驱动流动的差异。速度场是使用微 PIV 技术获得的。利用血液粘度的幂律模型开发了通道中血液速度的解析解。结果表明，红细胞聚集在流动的后期有影响，主要在速度剖面的钝度中观察到。在流动的初始阶段，剪切条件适度升高，防止形成强烈的 RBC 聚集体。随着通道内流动减速，红细胞聚集增加，影响流动特性。防止形成强烈的红细胞聚集体。随着通道内流动减速，红细胞聚集增加，影响流动特性。防止形成强烈的红细胞聚集体。随着通道内流动减速，红细胞聚集增加，影响流动特性。