This work deals with the zero shear rate (maximum velocity) position parameter λ of a steady laminar axial annular flow of power-law fluids especially polymeric ones. λ is involved in the shear rate, velocity profile and the flow rate calculations, which are essential for studies such as viscous dissipation, convective heat transfer and pressure drop prediction in annuli. However, the analytical explicit expression of λ remains unsolved despite some approximate solutions. In this paper, we will provide a simple and analytically demonstrable expression of λ so that it can be used for parametric investigations, identifications, sensitivity analysis etc. in terms of industrial or laboratory applications.

这项工作处理的 是幂律流体特别是聚合物流体的稳定层流轴向环形流的零剪切速率（最大速度）位置参数λ。λ参与剪切速率，速度分布和流速计算，这对于诸如粘性耗散，对流传热和环空压降预测等研究至关重要。但是，尽管有一些近似解，但λ的解析显式表达式仍未解决。在本文中，我们将提供一个简单且可分析证明的λ表达式，以便将其用于工业或实验室应用中的参数研究，鉴定，灵敏度分析等。