Simulation Study of Thermotropic LCPs and Prediction of Normal Stress Difference at High Shear Rate

2013 ◽  
Vol 28 (5) ◽  
pp. 470-482 ◽  
Author(s):  
A. Rahman ◽  
R. K. Gupta ◽  
S. N. Bhattacharya ◽  
S. Ray ◽  
F. Costa
Keyword(s):  
Shear Rate ◽  
Normal Stress ◽  
Simulation Study ◽  
Normal Stress Difference ◽  
High Shear Rate ◽  
High Shear ◽  
Stress Difference

scholarly journals Evaluating the exit pressure method for measurements of normal stress difference at high shear rates

2020 ◽  
Vol 64 (3) ◽  
pp. 739-750 ◽  
Author(s):  
Dahang Tang ◽  
Flávio H. Marchesini ◽  
Ludwig Cardon ◽  
Dagmar R. D’hooge
Keyword(s):  
Normal Stress ◽  
Normal Stress Difference ◽  
High Shear ◽  
Stress Difference ◽  
Shear Rates ◽  
Pressure Method ◽  
Exit Pressure ◽  
High Shear Rates

Viscoelastic Behavior of Disperse Systems with Silicone Oil and Different Fillers

2002 ◽  
Vol 12 (6) ◽  
pp. 297-302 ◽  
Author(s):  
Dimiter Hadjistamov
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Normal Stress ◽  
Silicone Oil ◽  
Flow Behavior ◽  
Normal Stress Difference ◽  
Filler Concentration ◽  
Stress Difference ◽  
Disperse Systems ◽  
First Normal Stress Difference

Abstract The rheological behavior of model suspensions with the silicone oil M20000 and different concentrations of Cab-o-sil TS 720 resp. Durcal 5 are compared. The increase of the Cab-o-sil concentration changes the flow behavior of the suspension from shear-thinning, to pseudoplastic, and to plastic flow behavior. The first normal stress difference rises at the same time at certain shear rate. The disperse systems with Durcal 5 keep the structural viscous behavior of the silicone oil even with a filler concentration of 40.5 wt%. The dependence of the first normal stress difference on shear rate represents for suspensions with Durcal 5 only one straight line with a slope of n = 2. The normal stress has double the amount of the silicone oil M20000 at given shear rate and is independent of the used Durcal 5 concentration. It was established that suspensions with the silicone oil M20000 have a first normal stress difference that can, depending on the filler type, either increase (with Cab-o-sil TS 720) or decrease (with Durcal 5) at certain shear stress with increasing filler concentration. It is to be supposed that the decrease of the normal stress at a given shear stress, with increasing Durcal concentration, is a softening effect, caused by the filler.

Research on Viscoelasticity and its Influence Factors of Polymer Solution

2012 ◽  
Vol 535-537 ◽  
pp. 1065-1069
Author(s):  
Yun Jian Zhou ◽  
Jiang Yan Lv ◽  
Di Wu
Keyword(s):  
Shear Rate ◽  
Polymer Solution ◽  
Normal Stress ◽  
Viscoelastic Fluid ◽  
Mass Concentration ◽  
Polymer Solutions ◽  
Influence Factors ◽  
Normal Stress Difference ◽  
Stress Difference ◽  
First Normal Stress Difference

The Wiesenberger number is a common dimensionless quantity to reflect the elastic effect of fluids. It’s usually applied in mechanical calculation of viscoelastic fluid and calculated by the first normal stress difference. So the first normal stress difference and Wiesenberger number are applied to describe the viscoelasticity of polymer solutions. Though many literature reviews on the viscoelasticity of polymer solutions have been reported, only a few studied the Wiesenberger number and the first normal stress difference of viscoelastic fluid. Since the corresponding relation between Wiesenberger number and mass concentration and salinity of polymer solution is not clear, HAAKE RS150 rheometer was used during all steady and dynamic shear experiments, effects of mass concentration and salinity on the visco-elasticity of polymer solution in low shear rate were discussed, first normal-stress difference and Wiesenberger number were calculated. Results show that: with the increase of mass concentration of polymer solution and the decrease of salinity, both first normal-stress difference and Wiesenberger number increase, the visco-elasticity of polymer solution increases; At the same shear rate, the higher the salinity is, the smaller the first normal stress difference is, the smaller the Wiesenberger number is and the less obvious the viscoelasticity is. The Wiesenberger number of ordinary polymer solution used in the oilfield is about 1 when the shear rate is 10s-1and salinity is 508mg/L.

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