scholarly journals Apparent wall slip effects on rheometric measurements of waxy gels

2021 ◽  
Vol 65 (2) ◽  
pp. 257-272
Author(s):  
Thiago O. Marinho ◽  
Flávio H. Marchesini ◽  
Márcia C. K. de Oliveira ◽  
Márcio Nele
Keyword(s):  
Wall Slip ◽  
Slip Effects ◽  
Apparent Wall Slip

WALL SLIP EFFECTS MEASURING THE RHEOLOGICAL BEHAVIOR OF ELECTRORHEOLOGICAL (ER) SUSPENSIONS

2012 ◽  
Vol 26 (01) ◽  
pp. 1250006 ◽  
Author(s):  
STEFFEN SCHNEIDER
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Flow Behavior ◽  
Wall Slip ◽  
Hydraulic Test ◽  
Slip Effects ◽  
Measured Flow ◽  
Wall Shear ◽  
Er Fluids ◽  
Electrorheological Suspensions

In this work, a new method to determine the wall shear stress was developed step by step. To determine the wall shear stress, methods of the suspension rheology are being used for the first time to characterize ER fluids. This work focuses on investigations of the flow behavior of electrorheological suspensions in flow channels with different geometries at different electrical field strengths. Careful interpretation of the results with respect to different gap geometries has shown that the measured flow curves should undergo a combination of corrections. As a result it can be shown that wall slip effects can be measured under application like conditions on a hydraulic test bench.

Wall Slip Effects on Dynamic Oscillatory Measurements

1988 ◽  
Vol 32 (6) ◽  
pp. 575-584 ◽  
Author(s):  
Ann S. Yoshimura ◽  
Robert K. Prud'homme
Keyword(s):  
Wall Slip ◽  
Slip Effects

Apparent Wall Slip in Capillary Rheometry of Viscoplastic Liquids

2005 ◽  
Author(s):  
Paulo R. Souza Mendes ◽  
Jose´ R. R. Siffert ◽  
Eduardo S. S. Dutra
Keyword(s):  
Shear Stress ◽  
Yield Stress ◽  
Wall Slip ◽  
Momentum Conservation ◽  
Conservation Equation ◽  
Jump Number ◽  
Capillary Rheometry ◽  
Viscosity Function ◽  
Novel Material ◽  
Apparent Wall Slip

We employ a recently proposed viscosity function (Souza Mendes and Dutra, 2004) to analyze the fully developed flow of yield-stress liquids through tubes. We first show that its dimensionless form gives rise to the so-called jump number, a novel material property that measures the shear rate jump that the material undergoes as the yield stress is reached. We integrate numerically the momentum conservation equation that governs this flow together with the generalized Newtonian Liquid model and the above mentioned viscosity function. We obtain velocity and viscosity profiles for the entire range of the jump number. We show that the friction factor f.Re curves display sharp peaks as the shear stress value at the tube wall approaches the yield stress. Finally, we demonstrate the existence of sharp flow rate increases (or apparent slip) as the wall shear stress is increased in the vicinity of the yield stress.

Diffusion-Layer Theory for Flows Under Apparent Wall Slip

1998 ◽  
Vol 63 (1) ◽  
pp. 132-140 ◽  
Author(s):  
Ondřej Wein
Keyword(s):  
Mass Transfer ◽  
Velocity Profile ◽  
Solid Surface ◽  
Diffusion Layer ◽  
Analytical Formula ◽  
Wall Slip ◽  
Slip Effect ◽  
Local Power ◽  
Overall Mass Transfer Coefficient ◽  
Apparent Wall Slip

An explicit analytical formula is given for the overall mass transfer coefficient between the bulk of flowing microdisperse liquid and a small but finite active part of a solid surface. The apparent wall slip effect inside a diffusion layer is reflected through the local power-law velocity profile, vx(z) = Bzp, and a distribution B = B(x,y) over the solid surface.

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