摘要:

The classical expression for determining viscosity from sphere fall velocity is Stokes' law. Stokes' law applies in the absence of wall and inertial effects. In the usual experimental apparatus there are wall effects and there may be inertial effects. The objective of this paper is to establish a correlation of wall and inertial corrections to Stokes' law in the range appropriate for falling sphere viscometry, and to present this correlation in a manner convenient for application. The desired correlation is presented in Table II and Figure 5 of the text. The new correlation should be useful in determining the viscosity of Newtonian fluids and in determining the zero shear rate viscosity of polymer solutions.

ISSN:0148-6055    

DOI:10.1122/1.549308

出版商:The Society of Rheology    

年代:1973

数据来源: AIP

摘要:

Stokes' law for determining viscosity from sphere fall velocity applies in the absence of wall, inertial, and end effects. One objective of this investigation was to establish a criterion for choosing a tube long enough to avoid end effects. The resulting criterion is as follows. ForL/D=2andd/D<0.125there are no observable end effects throughout the middle third of the fall tube, even for Re as large as 2. Another objective was to establish a correlation of simultaneous wall and end corrections to Stokes' law in the absence of inertial effects, for application in short tube viscometry. The desired correlation is presented in Figure 3 and Table I.

ISSN:0148-6055    

DOI:10.1122/1.549309

出版商:The Society of Rheology    

年代:1973

数据来源: AIP

摘要:

An experimental study of the non‐Newtonian viscosity μ and the principal normal stress differenceN1of solutions of polybutadiene, polystyrene, and their copolymers of varying microstructures has been carried out in decalin, decane, and their mixtures. Decane is a nonsolvent for polystyrene and a poorer solvent for polybutadiene than decalin. For the homopolymers and random copolymers, the viscosity and Weissenberg number(N1/σ12)at a constant shear rate decrease as the nonsolvent is added. For block copolymers, the opposite is observed. This is due to the polystyrene segments precipitating out in poor solvents and forming intermolecular aggregates. The SBS‐block copolymers tend to form viscoelastic gels because a three‐dimensional network with polystyrene crosslinks is formed. The simple SB‐block copolymers show thixotropic behavior with yield stress. This may be explained by the two‐phase structure being in the form of micelles in which the polystyrene aggregate are solubilized by the polybutadiene segments.

ISSN:0148-6055    

DOI:10.1122/1.549310

出版商:The Society of Rheology    

年代:1973

数据来源: AIP

摘要:

A measurement of normal stress differences in a shearing elastic liquid is accomplished through direct measurement of hole pressure. Gravity flow down an inclined channel is used and hole pressure is measured for slots perpendicular and parallel to the flow, as well as for a circular hole. The first and second normal stress differences are calculated under the assumption of second‐order fluid behavior. Dynamic data are compared and a discrepancy noted.

ISSN:0148-6055    

DOI:10.1122/1.549311

出版商:The Society of Rheology    

年代:1973

数据来源: AIP

摘要:

A theoretical and experimental study of the equilibrium interface configuration in stratified bicomponent tube flow of polymer melts is presented. In the theoretical analysis, the principle of minimum viscous dissipation is used to determine the energetically preferred interface configuration for the case of stratified flow of Newtonian fluids of differing viscosity. In the experimental analysis, it is demonstrated that both a nylon‐nylon and a xylene‐sugar water solution system attain the minimum viscous dissipation interface configuration under equilibrium conditions.

ISSN:0148-6055    

DOI:10.1122/1.549312

出版商:The Society of Rheology    

年代:1973

数据来源: AIP

ISSN:0148-6055    

DOI:10.1122/1.549324

出版商:The Society of Rheology    

年代:1973

数据来源: AIP

ISSN:0148-6055    

DOI:10.1122/1.549325

出版商:The Society of Rheology    

年代:1973

数据来源: AIP