This paper presents a method for measuring the viscosity of generalized Newtonian fluid directly in flows generated by flat-blade turbine impellers, which are commonly used for moderate mixing and dispersion. A flat-blade turbine with four blades is defined as a model system and analyzed through numerical simulations with experimental verification. Carbopol 940 solution, a high viscosity non-Newtonian fluid with a yield stress, and a bentonite based drilling mud solution were selected as test fluids. Numerical simulation techniques for flow in agitators with a yield stress was established using the rotating coordinate system and flow solutions were validated with experiments by comparing the torque on the impeller shaft. The Metzner-Otto constant and the energy dissipation rate constant were predicted by numerical simulations using the Metzner-Otto correlation and validated via experiments. The effective viscosity that reproduces total energy dissipation rate identical to that of a Newtonian fluid was obtained from both numerical and experimental methods at different impeller speeds, from which the material viscosity curve was established as a function of the shear rate. The accuracy of viscosity prediction was compared with a rheological measurement and the average relative error was below 12% and 7% in the experiment and simulation, respectively. This method has the advantage of being able to measure the in-situ viscosity, where a drilling mud needs to transport more and heavier cuttings and careful preparation of the mud is key issue to a successful drilling process.

中文翻译：

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平板涡轮叶轮搅拌器中过程粘度的比较数值和实验研究

本文提出了一种方法，用于直接测量通常用于中等混合和分散的平叶涡轮叶轮产生的流动中的广义牛顿流体的粘度。将具有四个叶片的平叶片涡轮机定义为模型系统，并通过带有实验验证的数值模拟进行分析。选择Carbopol 940溶液，具有屈服应力的高粘度非牛顿流体和基于膨润土的钻井泥浆溶液作为测试流体。利用旋转坐标系建立了带有屈服应力的搅拌器内流动的数值模拟技术，并通过比较叶轮轴上的扭矩，通过实验验证了流动解。使用Metzner-Otto相关性通过数值模拟预测了Metzner-Otto常数和能量耗散率常数，并通过实验进行了验证。通过数值和实验方法，在不同的叶轮速度下，获得了与牛顿流体相同的，能再现总能量耗散率的有效粘度，由此建立了材料粘度曲线与剪切速率的函数关系。将粘度预测的准确性与流变测量结果进行了比较，在实验和模拟中，平均相对误差分别低于12％和7％。这种方法的优点是能够测量原位粘度，