Results were presented on the power consumption by agitation accompanied by aeration. Analysis of the power led to the introduction of dimensionless term
NA and it was found possible to correlate the power consumption with
NA.
(1)
Principal data were obtained with the impellers shown in
Fig. 4. Tanks used were respectively of diameters 27.4cm, 20 and 16.5cm. The air inlet nozzles were settled beneath the center of agitation (Fig. 2). The following are the relative dimensions held throughout the experiments.
Results are summarized as follows;
1) With the paddle, the relation (1) holds good as was illustrated in
Fig. 5. (P
g/P
0) first decreases with the increase of
NA and then it shows a tendency to have a definite value with
NA which is larger than 4×10
-2.
2) With a vaned disk, there exist the limiting rotational speeds
nc which are the function of D
i.
The relation (1) holds fairly good with the rotational speeds, larger than
nc.
The number of blades has remarkably important effects on power consumptions, which was shown
Fig. 8.
3) With the turbine, the relation (1) holds good with engineering estimation as was illustrated in
Fig. 11.
4) The position and diameters of air inlet nozzles have little effects on power characteristics.
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