scholarly journals EXPERIMENTAL STUDY OF THE FLOW DYNAMICS OF COMPLEX VISCOELASTIC FLUID THROUGH HYPERBOLIC CONTRACTION/EXPANSION

2020 ◽  
pp. 76-94
Author(s):  
Muñoz Garduño Kevin David ◽  
Pérez Camacho Mariano
Keyword(s):  
Pressure Drop ◽  
Shear Flow ◽  
Extensional Flow ◽  
Viscoelastic Fluids ◽  
Excess Pressure ◽  
Flow Dynamics ◽  
Shear Type ◽  
Flow Through ◽  
Expansion System ◽  
Hyperbolic Contraction

The main objetive of this work was to experimentally study the Flow dynamics of viscoelastic fluids (Boger fluid and Hase) when they flow through a contraction/expansion system defined by a hyperbolic tube, therefore through equations analogous to the Hagen-Poiseuille equation, the pressure drop associated with the viscous interaction was quantified, and subsequently the excess pressure drop (EPD), a parameter associated with the elasticity of viscoelastic fluids, conducting comparative studies with respect to a Newtonian reference for the same shear viscosity value, which allowed observing shear speed intervals where three predominant zones were observed. The first of them of shear type coinciding with the trajectories of the Newtonian fluid of identical viscosity value, the second zone was attributed to the elastic manifestation of the fluids due to the preferential development of the extensional flow that is in constant competition with the shear flow within of the same geometry. The third zone was attributed to a predominance of the shear flow over the extensional one, because of to the fact that the hyperbolic geometry favors the development of this type of flow at high values of shear rate KEYWORDS: Excess pressure drop; Extensional flow; Hyperbolic contractions

Creeping Flow Through an Axisymmetric Sudden Contraction or Expansion

2001 ◽  
Vol 124 (1) ◽  
pp. 273-278 ◽  
Author(s):  
Sourith Sisavath ◽  
Xudong Jing ◽  
Chris C. Pain ◽  
Robert W. Zimmerman
Keyword(s):  
Pressure Drop ◽  
Expansion Ratio ◽  
Excess Pressure ◽  
Creeping Flow ◽  
Numerical Studies ◽  
Equivalent Length ◽  
Sudden Contraction ◽  
Circular Orifice ◽  
Flow Through ◽  
Infinite Wall

Creeping flow through a sudden contraction/expansion in an axisymmetric pipe is studied. Sampson’s solution for flow through a circular orifice in an infinite wall is used to derive an approximation for the excess pressure drop due to a sudden contraction/expansion in a pipe with a finite expansion ratio. The accuracy of this approximation obtained is verified by comparing its results to finite-element simulations and other previous numerical studies. The result can also be extended to a thin annular obstacle in a circular pipe. The “equivalent length” corresponding to the excess pressure drop is found to be barely half the radius of the smaller tube.

Predicting the excess pressure drop incurred by LPTT fluids in flow through a planar constricted channel

2019 ◽  
Vol 31 (3) ◽  
pp. 149-166
Author(s):  
Taha Rezaee ◽  
Mostafa Esmaeili ◽  
Solmaz Bazargan ◽  
Kayvan Sadeghy
Keyword(s):  
Pressure Drop ◽  
Excess Pressure ◽  
Flow Through ◽  
Constricted Channel

Anomalous pressure drop behaviour of mixed kinematics flows of viscoelastic polymer solutions: a multiscale simulation approach

2009 ◽  
Vol 631 ◽  
pp. 231-253 ◽  
Author(s):  
ANANTHA P. KOPPOL ◽  
RADHAKRISHNA SURESHKUMAR ◽  
ARASH ABEDIJABERI ◽  
BAMIN KHOMAMI
Keyword(s):  
Pressure Drop ◽  
Newtonian Fluid ◽  
Flow Rate ◽  
Extensional Flow ◽  
Flow Simulation ◽  
Multiscale Simulation ◽  
Excess Pressure ◽  
Micromechanical Models ◽  
Polymeric Solutions ◽  
Corner Vortex

A long-standing unresolved problem in non-Newtonian fluid mechanics, namely, the relationship between friction drag and flow rate in inertialess complex kinematics flows of dilute polymeric solutions is investigated via self-consistent multiscale flow simulations. Specifically, flow of a highly elastic dilute polymeric solution, described by first principles micromechanical models, through a 4:1:4 axisymmetric contraction and expansion geometry is examined utilizing our recently developed highly efficient multiscale flow simulation algorithm (Koppol, Sureshkumar & Khomami, J. Non-Newtonian Fluid Mech., vol. 141, 2007, p. 180). Comparison with experimental measurements (Rothstein & McKinley, J. Non-Newtonian Fluid Mech., vol. 86, 1999, p. 61) shows that the pressure drop evolution as a function of flow rate can be accurately predicted when the chain dynamics is described by multi-segment bead-spring micromechanical models that closely capture the transient extensional viscosity of the experimental fluid. Specifically, for the first time the experimentally observed doubling of the dimensionless excess pressure drop at intermediate flow rates is predicted. Moreover, based on an energy dissipation analysis it has been shown that the variation of the excess pressure drop with the flow rate is controlled by the flow-microstructure coupling in the extensional flow dominated region of the flow. Finally, the influence of the macromolecular chain extensibility on the vortex dynamics, i.e. growth of the upstream corner vortex at low chain extensibility or the shrinkage of the upstream corner vortex coupled with the formation of a lip vortex that eventually merges with the upstream corner vortex at high chain extensibility is elucidated.

Analysis of Viscoelastic Flows Through Converging-Diverging Channels

2004 ◽  
Author(s):  
Mauricio Lane ◽  
Moˆnica F. Naccache ◽  
Paulo R. Souza Mendes
Keyword(s):  
Pressure Drop ◽  
Newtonian Fluid ◽  
Geometric Mean ◽  
Viscoelastic Fluids ◽  
Momentum Conservation ◽  
Viscoelastic Flows ◽  
Generalized Newtonian Fluid ◽  
Fluid Behavior ◽  
Fluent Software ◽  
Flow Through

In this work, the flow of viscoelastic fluids through axisimmetric converging-diverging channels is analyzed. The solution of mass and momentum conservation equations is obtained numerically via finite volume technique using the Fluent software. The Generalized Newtonian Fluid constitutive equation was used to model the non-Newtonian fluid behavior, using the Shunk-Scriven model for the viscosity, where a weighted geometric mean between shear and extensional viscosities is assumed. The results of pressure drop are compared to the ones predicted by a previously proposed simplified relation (Souza Mendes and Naccache, 2002) between pressure drop and flow rate, for viscoelastic fluids flow through porous media, in order to analyze its performance.

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