Non-Newtonian dynamics

Non-Newtonian Dynamics-Based Iterations for Molecular Sampling... 

Liquid phase used aqueous glycerol (Newtonian) and xanthan gum (non-Newtonian). Dynamic step pressure method— oxygen as the solute... 

Computer modelling provides powerful and convenient tools for the quantitative analysis of fluid dynamics and heat transfer in non-Newtonian polymer flow systems. Therefore these techniques arc routmely used in the modern polymer industry to design and develop better and more efficient process equipment and operations. The main steps in the development of a computer model for a physical process, such as the flow and deformation of polymeric materials, can be summarized as ... 

Townsend, P. and Webster, M. I- ., 1987. An algorithm for the three dimensional transient simulation of non-Newtonian fluid flow. In Pande, G. N. and Middleton, J. (eds). Transient Dynamic Analysis and Constitutive Laws for Engineering Materials Vul. 2, T12, Nijhoff-Holland, Swansea, pp. 1-11. 

For laminar flow of power law fluids in channels of noncircular cross section, see Schecter AIChE J., 7, 445 48 [1961]), Wheeler and Wissler (AJChE J., 11, 207-212 [1965]), Bird, Armstrong, and Hassager Dynamics of Polymeric Liquids, vol. 1 Fluid Mechanics, Wiley, New York, 1977), and Skelland Non-Newtonian Flow and Heat Transfer, Wiley, New York, 1967). 

For non-Newtonian drilling fluids, the concept of an effective viscosity can be used to replace the dynamic viscosity in Equation 4-89. 

Dynamic similarity occurs in two geometrically similar units of different sizes if all corresponding forces at counterpart locations have a constant ratio. It is necessary here lo distinguish between the various types of force inertial, gravitational, viscous, surface tension and other forms, such as normal stresses in the case of viscoelastic non-Newtonian liquids. Some or all of these forms may be significant in a mixing vessel. Considering... 

Molecularly motivated empiricisms, such as the solubility parameter concept, have been valuable in dealing with mixtures of weakly interacting small molecules where surface forces are small. However, they are completely inadequate for mixtures that involve macromolecules, associating entities like surfactants, and rod-like or plate-like species that can form ordered phases. New theories and models are needed to describe and understand these systems. This is an active research area where advances could lead to better understanding of the dynamics of polymers and colloids in solution, the rheological and mechanical properties of these solutions, and, more generally, the fluid mechaiucs of non-Newtonian liquids. 

Shah, S.N. "Proppant Settling Correlations for Non-Newtonian Fluids Under Static and Dynamic Conditions," SPE paper 9330, 1980 Annual Fall Technical Conference and Exhibition of the SPE of AIME, Dallas, September 21 24. 

It is also evident that this phenomenological approach to transport processes leads to the conclusion that fluids should behave in the fashion that we have called Newtonian, which does not account for the occurrence of non-Newtonian behavior, which is quite common. This is because the phenomenological laws inherently assume that the molecular transport coefficients depend only upon the thermodyamic state of the material (i.e., temperature, pressure, and density) but not upon its dynamic state, i.e., the state of stress or deformation. This assumption is not valid for fluids of complex structure, e.g., non-Newtonian fluids, as we shall illustrate in subsequent chapters. 

Viscosity, defined as the resistance of a liquid to flow under an applied stress, is not only a property of bulk liquids but of interfacial systems as well. The viscosity of an insoluble monolayer in a fluid-like state may be measured quantitatively by the viscous traction method (Manheimer and Schechter, 1970), wave-damping (Langmuir and Schaefer, 1937), dynamic light scattering (Sauer et al, 1988) or surface canal viscometry (Harkins and Kirkwood, 1938 Washburn and Wakeham, 1938). Of these, the last is the most sensitive and experimentally feasible, and allows for the determination of Newtonian versus non-Newtonian shear flow. 

De Witt T., Mezner. W. A rheological equation of state which predicts non-Newtonian viscosity, normal stresses and dynamics module. J. Appl.Phys., 1985, v. 26, p. 889-892. 

Dewsbury, K. H., Karamanev, D. G. and Margaritis, A. AIChEJl 46 (2000) 46. Dynamic behavior of freely using buoyant solid sphere in non-Newtonian liquids. 

In carrying out a scale-up, the industrial process has to be similar to the laboratory process in every relation. Besides the geometric and process-related similarity, it is self-evident that also the fluid dynamics of the material system has to behave similarly. This requirement represents normally no problems when Newtonian fluids are treated. But it can cause problems, e.g., in some biotechnological processes—when material systems are involved which exhibit non-Newtonian viscosity behavior. Then the shear stress exerted by the stirrer causes a viscosity held. 

The dynamic moduli for infinitesimal superimposed deformations parallel and transverse to the flow direction in steady shearing flow should be unaffected by flow if the shear rate is sufficiently small. According to the theory of simple fluids, the superimposed dynamic moduli for shearing flows in the non-Newtonian region must change in order to conform with the relations (370,372 ... 

Kotaka,T., Osaki,K. Normal stresses, non-Newtonian flow, and dynamic mechanical behavior of polymer solutions. J. Polymer ScL Pt.C 15,453-479 (1966). 

Fixman,M. Polymer dynamics non-newtonian intrinsic viscosity, J. Chem. Phys. 45, 793-803 (1866). 

Booij.H.C. Influence of superimposed steady shear flow on the dynamic properties of non-Newtonian fluids. Rheol. Acta 5,215-221 (1966). 

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