Extensional deformation of non-Newtonian liquid bridges
Extensional deformation of non-Newtonian liquid bridges
复制标题
非牛顿液桥的拉伸变形
DOI：
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
G. McKinley
中科院分区：
文献类型：
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作者：
S. Gaudet;G. McKinley
摘要提出了一种数值模拟非牛顿流体在拉伸流变仪中拉伸动力学的方法。边界元法，结合Oldrophil-B或广义多模上对流麦克斯韦本构模型，被用来计算的瞬态演化的液体界面，施加在固定端板和聚合物的应力。数值计算结果与实验结果进行了比较，并在低亨基应变（牛顿响应），但在较高的应变在实验中观察到的应力增长提供不太准确的建模是在很好的协议。比较不同的方法来测量的表观拉伸粘度从全球测量的净力和中点半径的细丝。在大应变计算表明，在这些设备中的流体运动非常接近理想的单轴伸长。
Abstract A numerical method for simulating the extensional dynamics of elongating filaments of non-Newtonian fluids in a filament stretching rheometer is presented. The boundary element method, in conjunction with either the Oldroyd-B or the generalized multimode Upper-Convected Maxwell constitutive model, is used to calculate the transient evolution of the liquid interface, the applied force on the stationary end plate and the polymeric stresses. The numerical results are compared to experimental results and are in excellent agreement at low Hencky strains (Newtonian response) but provide less accurate modeling of the stress growth observed in experiments at higher strains. A comparison of different methods for measuring the apparent extensional viscosity from global measurements of the net force and the mid-point radius of the filament is presented. At large strains calculations show that the fluid motion in these devices closely approximates ideal uniaxial elongation.