Rheology and Dynamics of Water-in-Oil Emulsions under Steady and Dynamic Shear Flow
Rheology and Dynamics of Water-in-Oil Emulsions under Steady and Dynamic Shear Flow
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DOI：
10.1006/jcis.1996.4592
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发表时间：
1997-01
影响因子：
9.9
通讯作者：
Lee;Lee;Park
中科院分区：
文献类型：
--
作者：
Lee;Lee;Park
考虑了油包水型乳状液流变学的基本方面，如粘度比和形态。该模型是在前人工作的基础上，结合Lee和Park（1994）的形态学理论，建立的。因此，所提出的概念使我们能够预测不仅絮凝的程度，而且粘度比和形态的影响。通过使用因子-α“q”xy/γ i（其中α“是界面张力，q”xy是各向异性张量的xy分量，γ i是剪切速率），发现了由液滴絮凝引起的次级形态对分散乳液粘度的贡献。然而，这种方法仅适用于低于最大无规堆积浓度的系统。在实验上，研究了乳液在稳态和动态剪切流场中的体相流变特性，探讨了乳液的结构。在剪切速率扫描过程中观察到絮凝-反絮凝转变，导致在临界剪切速率γ附近的粘度的瞬时不稳定性;约100 s-1。
The fundamental aspects governing the rheology of water-in-oil emulsions, such as viscosity ratio and morphology were considered. The model developed here is based on the early work of Pal and Rhodes (1989) for viscosity equation, combined with the theory of Lee and Park (1994) for the morphological contributions. Thus, the proposed conception enables us to predict not only the degree of flocculation but also viscosity ratio and morphological effects. The contribution of secondary morphology caused by the flocculation of droplets on the viscosity of dispersed emulsions has been found by using the factor, -alpha'q'xy/gamma; (where alpha' is the interfacial tension, q'xy is xy-component of anisotropy tensor, and gamma; is shear rate). However, this approach is only useful for system below the maximum random packing concentration. Experimentally, the bulk rheological properties have been examined under steady and dynamic shear flow to investigate the structure of emulsion. The flocculation-deflocculation transition was observed during the shear rate sweep, resulting in instant dilatancy of viscosity near the critical shear rate gamma; approximately 100 s-1.