黏弹流体动态黏度数学模型与实验研究

Modeling of Dynamic Viscosity of Viscoelastic Fluids and Corresponding Experimental Investigation

针对经典Maxwell本构模型的局限性进行了相应的非线性修正,提出了一种新的黏弹本构模型,利用修正模型和基于黏性耗散机理建立的黏滞动力方程,得到了振动剪切流场黏弹流体的动态黏度函数。通过将动态黏度函数应用于简单振动剪切流,得到了与传统计算方法相一致的结果。最后,进行了同轴圆筒动态流变实验。实验数据与垂直叠加振动剪切流场中LDPE熔体黏度的理论值进行了对比,发现动态黏度函数在小振幅范围内具有较好的预测能力。

In respect to certain limitation of classic Maxwell constitutive equation, a new nonlinear modification of the viscoelastic constitutive equation was proposed. By using the constitute equation and a viscous dynamic equation, which was characterized by viscous dissipation mechanism, a function of dynamic viscosity of viscoelastic fluids in transient shear flows was derived. Same result was obtained as using the traditional method, when using the dynamic viscosity function to calculate simple vibrating shear flow. Finally, dynamic rheologic experiments were carried out on a coaxial barrel rheometer, and an agreement was investigated between the experimental data and theoretical predictions.