Flow regime 372 INDEX

As liquid flowrate inereases beyond the minimum required to suspend the partieles, the bed expands. Unfortunately, however, the expansion index n is not eonstant over all flow regimes but is a funetion of the flow. Thus... 

Interestingly, it turns out that despite the differing functions of the expansion index, , the correction factor, g(e), is approximately constant at the extremes of the flow regimes due to the particular values of the expansion index. The value of n is not known entirely theoretically but can be obtained from the Richardson and Zaki equation. Thus At low RCp ( = 4.6)... 

Here, k is the fluid consistency index and m the flow behavior index. While no data for a gassed system under laminar and transition flow were reported, Pg is expected to depend on impeller dimensions in these regimes. 

Po Re in the laminar regime constant for jet mixing time correlation (= 3.00) power law exponent or flow behavior index number of blades, helical ribbon impeller impeller rotational speed (rps)... 

At the critical value when Ng = 40, the flow transition between saltation and heterogeneous regimes occurs. This statement infers that when < 40 saltation occurs, and when Ng > 40 heterogeneous flow develops. These results, based on a mixture of different particle sizes, did not apply to the work of Blatch (1906), who concentrated on particles of a uniform size (sand 20 30 mesh in water). Babcock (1967) reinterpreted this work and demonstrated that for finely graded particles the transition occurred at an index number of 10. It is obvious that a complex mixture of particles of different sizes can increase the magnitude of the transition index number. 

The different approach regimes suggest that an index comparing the rates of change of [m] due to the polymerization reaction and, separately, due to the flow, will be useful. With this, the approach index can be defined as ... 

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