Flow of suspensions

Though experimental data on suspensions of fibers in Newtonian dispersion media give more or less regular picture, a transition to non-Newtonian viscoelastic liquids, as Metzner noted [21], makes the whole picture far or less clear. Probably, the possibility to make somewhat general conclusions on a longitudinal flow of suspensions in polymer melts requires first of all establishing clear rules of behavior of pure melts at uniaxial extension this problem by itself has no solution as yet. 

Kopko et al.m made measurements of the pressure drop for the flow of suspensions of iron shot (0.0734-0.131 mm diameter) in a vertical pipe 61 mm diameter and 4.3 m tall. 

Shook, C. A. and Daniel, S. M. Can. J. Chem. Eng. 43 (1965) 56. Flow of suspensions of solids in pipelines. Part I. Flow with a stable stationary deposit. 

Sergre, G. and Silberberg, A. Nature 189 (1961) 209. Radial particle displacements in Poiseuille flow of suspensions. 

Herzig IP, Leclerc DM, LeGoff P (1970) Flow of suspensions through porous media—Application to deep filtration. Ind Eng Chem 62 8-35... 

The pressure drop resulting from the movement of particles can be determined by an energy balance. The overall energy balance round the flow of suspension inside the accelerating tube is written as... 

Nasr-El-Din, H.A. Flow of Suspensions in Pipelines in Suspensions, Fundamentals and Applications in the Petroleum Industry, Schramm, L.L. (Ed.), American Chemical Society Washington, 1996, pp. 177—225. 

S. Bhattacharji and P. Savic, Real and Apparent Non Newtonian Behavior in Viscous Pipe flow of Suspensions Driven by a Fluid Piston, Proc. Heat and Mass Transfer Fluid Mechanics Institute, 15, 248 (1965). 

That is, for separating a given size at a fixed y-position of the cylinder all that is required is to vary the flow of suspension through the cylinder. 

Nagatani [57] arrived at a similar equation he presented a generalized theory describing slow viscous flow of suspensions in terms of statistical continuum mechanics. 

From Fig. 3.15 we can note that, by analogy to the 2 bar constant pressure case, example FIS shows a new special case where we have positive and small negative values in the concentrated suspension flow rate at the plant exit. This result can be explained by the background noise in the measurement of the flow of suspension. Nevertheless, the mean value of the flow rate is small but positive. If the efficiency of the filtration at constant pressure is given by the solid concentration ratio between the exit and fresh suspensions, then, as shown in Fig. 3.13, the ratio is always lower than 2 for operation case F2/1.6. For cases FI and FIS, this ratio increases permanently, non-uniformly and attains values over 12 g/1 in the proximity of the complete clogging state. 

The operating principle of the instrument may be followed by referring to Figure 9.2. The sample to be analyzed is dispersed in an electrolyte that is placed in a beaker. The glass sample tube, on either side of which there is a platinum electrode, is immersed in the electrolyte. A controlled vacuum initiates flow of suspension through a sapphire orifice let into the glass tube and unbalances a mercury siphon. 

W weight of tank contents, lb G — rate of flow of suspension, Ib/hr Ts = temperature of steam, °F... 

Wall effects in capillary flow of suspensions such as apple sauce occur as a result of velocity gradient near the wall that in turn causes the suspended particles to move away from the wall region. The net result is slip of the fluid at the wall (23., 24.) The correct shear rate can be calculated from flow rates corrected for slip. The procedure, due to Mooney (42.), requires the use of several capillaries of different different length to diameter ratios has been applied to food suspensions by Higgs (38) and Kokini and Plutchok (22.) to show that slip effects are significant. These results also suggest caution in using... 

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