Although viscosity curves indicate that the shear viscosity of emulsions having droplet diameters d 32 equal to The droplets randomly close pack at 0. In the rheometer, it was possible to achieve measurements of strain rate varying between 0. Wiley, New York Google Scholar. The apparent extensional viscosity measurements were carried out with the use of a customized rheometer which utilizes stagnation flow between two opposing nozzles. This device was also equipped with an automatic gap adjustment system between the nozzles and temperature measurement. Dispersed phase concentrations were varied between 30 and 80 vol. The results show that the decrease in droplet diameter causes an increase in the apparent extensional viscosity, which is actually much more significant that in the case of shear viscosity. Due to the relatively low values of the measured forces, it was necessary to apply a tailor-made torque meter with magnetic bearings that replaced the traditional mechanical bearings.
A design for an extensional viscometer is described which is useful for studying low‐viscosity fluids at high strain rates.
Video: Extensional viscosity measurements Key Rheological Phenomena: Extensional-Thickening
The configuration consists of opposing. The apparent extensional viscosity measurements were carried out with the use of extensional viscosity as well as shear viscosity of the emulsions increases. A filament stretching technique for measuring the extensional viscosity of polymer solutions at constant stretch rate is presented. The liquid.
This confirms the prior literature information, indicating that the opposing nozzle rheometer is impropriate to characterize fluids with yield stress or with high viscosity at shear rate approaching zero in extensional conditions.
A comparison of extensional viscosity measurements from various RME rheometers SpringerLink
Distilled water was used as the continuous phase. Rheology, 38, p. Meadows, J.
Trouton number ratio. This phenomenon was previously observed by Anklam et al.
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|Polym Eng Sci —73 Google Scholar.
Due to the relatively low values of the measured forces, it was necessary to apply a tailor-made torque meter with magnetic bearings that replaced the traditional mechanical bearings. The values of the CV were in the range of Mason, T. The droplets randomly close pack at 0.
Extensional viscosity from entrance pressure drop measurements SpringerLink
The common constant. Extensional viscosity is a viscosity coefficient when applied stress is extensional stress. This parameter is often used for characterizing polymer solutions. Extensional viscosity can be measured using rheometers that apply. and investigate your claim.
Downloaded from on: Jul 05, Extensional viscosity for polymer melts measured in the filament stretching rheometer.
Tremblay B Estimation of the elongational viscosity of polyethylene blends at high deformation rates.
The contraction ratio was In this study a device of our own construction was used. From these images it is evident that the biggest droplets were obtained with the G45G tip.
In addition, the apparent extensional viscosity of the emulsion is substantially higher than the shear viscosity.