Wall Slip Effects

Over the twentieth century, the mbber industry has developed special rheometers, essentially factory floor instmments either for checking process regularity or for quality control purposes, for instance, the well-known Mooney rheometer (1931), the oscillating disk rheometer (1962), and the rotorless rheometer (1976). All those instmments basically perform simple drag flow measurements but they share a common feature During the test, the sample is maintained in a closed cavity, under pressure, a practice intuitively considered essential for avoiding any wall slip effects. Indeed it has... 

Riljanski, T. 1989. A mefliod for correction of the wall-slip effect in a Couette rheometer. Rheol. Acta 28 61-64. 

Yoshimura, A. and Prud homme, R. K. 1988b. Wall slip effects on dynamic oscillatory measurements. J. Rheol. 32 575-584. 

The difference between single and twin-bore capillary rheometers (Fig. 9) cannot be dealt with in this contribution. Basically this is a matter of being able to make the so-called Bagley correction with less effort and fewer errors. Likewise, no reference can be made here as to how dilatant respectively structural viscose behaviour (Rabinowitsch correction) and the strain properties of ceramic bodies or wall slipping effects (according to the Mooney method) can be determined with the capillary rheometer. 

Numerous workers have described the role of wall-slip effects on measurements made with conventional smooth-walled geometries [Barnes, 1995]. Slip can occur in suspensions at high (ca. 60%) solids volume fiaction, and can involve fluctuating torque in a rotational viscometer under steady... 

Molecular simulations of Knudsen wall-slip effect of wall morphology. Mol. 

Heywood (l991) discussed errors with the use of rotating viscometers. Particular sources of errors are the end effects from both cylinders and the possible deformation of the laminar layer under the effect of high rotational speed. Heywood recommended the use of cylinders with a tong tength to diameter ratio. Wall slip effects can be detected by using cylinders of different radius but same length. The vendors of rheometers publish equations to correct for watt sUp and end effects. 

Durairaj, R., Mallik, S., Seman, A. Ekere, N.N. (2009a). Investigation of Wall-Slip Effect on Lead-Free Solder Paste and Isotropic Conductive Adhesives. Sadhana, Vol. 34, No.5, (October 2009), pp. 799-810. 

Gevgilili, H., Kalyon, D. M. Step strain flow Wall slip effects and other error sources. /. RheoL (2001) 45, pp. 467-475... 

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