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Impeller Flow
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This is a continuation of the
Process Intensifier - Optimization with CFD: Part 1 paper.
Although the flow number, Nq, of the impellers could be
determined using the
CFD and integrating the velocities over the area of the impeller, it was not
done in this study. We can estimate the flow number fairly well from the
literature. The exact number is not important for this discussion, though. We
assumed that Nq = 1.1 for each impeller in LTR and Nq = 1.2 for each impeller in
HGR. We assumed Nq = 0.56 for the axial flow impellers.
| 1750 RPM |
Radial Process Intensifier |
Axial Process Intensifier |
|
GPM (m3/s) |
R650 |
R1100 |
GPM (m3/s) |
R650 |
R1100 |
| Lightnin |
1042 (0.0657) |
1.60 |
0.95 |
182 (0.0115) |
0.28 |
0.17 |
| Hayward Gordon |
1136 (0.0717) |
1.75 |
1.03 |
530 (0.0335) |
0.82 |
0.48 |
| Table
5: Estimated flow generated by the impellers in GPM (m3/s), and the
ratios, R, of impeller flow to pipe flow rate (at 650 and 1100 GPM (at
148 m3/hr and 250 m3/hr)). |
Table 5 is very interesting. As a rule-of-thumb for continuous
processes, the
impeller generated flow should be at least 3 times the throughput. As we can see
here, not one of these devices complies. Even the LTA appears to be doing some
mixing at 650 GPM, which has R = 28% or about 1/4th the pipe flow rate. LTA
seems to have lost its mixing ability at 1100 GPM. Perhaps the rule-of-thumb for
Process Intensifiers is that impeller generated flow should be at least 1/4th
the pipe throughput.
Continue with Residence Time Distributions
or
Go back to Results
or
Go back to the Title Page
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