Poiseuille流动初始阶段存在速度发展的非稳态过程,会对测试结果造成偏差.为分析非稳态Poiseuille流动过程对测量黏度造成的偏差,以不可压缩牛顿流体为例,进行恒流量边界与非定常流量边界下的非稳态Poiseuille流动过程研究.以无量纲黏度和无量纲时间表征非稳态过程,建立数值模型,计算给出恒平均速度边界、从0线性增加平均速度边界和恒压力边界条件下无量纲黏度数值的变化规律.结果表明:非稳态过程中无量纲黏度数值随时间逐渐减小并最终趋于1,且不同边界条件下流动达到稳定对应的无量纲时间为定值.当边界类型确定时,非稳态过程的无量纲黏度数值可视为仅与无量纲时间有关的函数;对于不同类型边界条件,从0线性增加的平均速度边界、恒压力边界、恒平均速度边界条件对应的非稳态过程逐渐缩短.%At the initial stage of Hagen-Poiseuille flow, there is an unsteady process for the velocity developing which will cause deviation on the results of measurement. In order to analyze the deviation caused by the unsteady Poiseuille flow for the viscosity measurement,studies were carried out through a numerical model. Taking the incompressible Newtonian fluid as an example,we studied the unsteady Poiseuille flow process at a constant flow rate and unsteady flow rate boundary conditions. The dimensionless viscosity and dimensionless time were used to reflect the unsteady process and a numerical model was built. The variation rules of the dimensionless viscosity under the boundaries of the constant average velocity,the average ve-locity which increases linearly from 0,and the constant pressure drop were given via numerical calculations. It was found that dimensionless viscosity falls to 1 with the time increasing and the non-dimensional time is a constant when the flow attains the stable state under different boundary conditions. When the types of boundary conditions are decided,the dimensionless vis-cosity can be viewed as a function only with respect to the dimensionless time in the unsteady process. For different types of boundary conditions,the unsteady processes reduce corresponding to the boundary conditions of the constant average veloci-ty,the constant pressure drop,and the average velocity which increases linearly from 0.
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