Maxwell orthogonal rheometer

Steady-State Maxwell Orthogonal Rheometer Flow [Warner and Bird (75)J... 

The quantities in Eqs. (21.6) and (21.7) are tj (Q) and tj"(Q) where tj and rf are the quantities defined in 7 for the small amplitude oscillatory experiment. Hence when the limit is taken as T->0, xXJ(—QY) - rj and xyJ(— QY)->t)". The same limiting result was obtained for this flow by Bird and Harris (4) using an integral continuum model. Thus, this gives additional support to the argument that the Maxwell orthogonal rheometer flow provides the possibility of measuring the dynamic properties of fluids. 

As an example of a flow which is neither a shearing flow or an elon-gational flow we consider the Maxwell orthogonal rheometer flow (see Fig. 10). In this flow the velocity profile is = — Q y — Yz), = Qx, and Uj = 0 where T = ajl. Here the diffusion equation is obtain from Eq. (3.9) with the first line of the right side omitted, and Eqs. (3.11) and (3.12) with Q, YQ, and k = Q ... 

Gent (1960) first published an ERD experiment using vulcanized rubber. He reports that his inspiration came from Maxwell s rotating cantilever rod experiments. Mooney (1934) also tried the geometry on gum rubbers. Maxwell and Chartoff (1965) carried out the first tests on polymer melts. Maxwell s (1967) experiments caused the geometry to become known as the Maxwell orthogonal rheometer. 

Note that in the literature this geometry js called the Maxwell orthogonal rheometer or eccentric rotating disks, ERD (Macosko and Davis, 1974 Bird, et al., 1987, also see Chapter 5). Usually, the coordinates X2 = > and X3 = z are used. 

In the Maxwell orthogonal rheometer (Fig. 18.18), material is sheared between two parallel disks of radius R, separated from one another by a distance h, each rotating at the same steady angular frequency a>, but with their axes of rotation displaced by a distance d. Transducers are set up to measure three steady, orthogonal force components (hence the name) on one of the disks, f, Fy, and Fg. 

NMR applied to polymer structure analysis Maxwell, orthogonal rheometer... 

Fig. 10. Schematic diagram of the orthogonal rheometer [Maxwell and Chartoff (55)) both circular disks rotate with the same steady angular velocity Q...

Maxwell, B. and Chartoff, R.P. (1965) Studies of polymer melts in an orthogonal rheometer, Trans. Soc. RJieol, 9,41-52. 

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