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4.5 Evaluation 161
Rotation rate (rpm)
115 215

0
Depth (mm) 100 mm s -1

6

Fig. 4.59. Velocity vectors around optical mixer for vertical rotation, with obser-
vation depth and rotation rate as parameters

Average flux amount (mm) 40 215 rpm

155
20
115

0
0 2 4 6 8 10 12
Distance from focal point (mm)
Fig. 4.60. Average flux amount at different depths for vertical rotation, rotation
rate as a parameter

wing, expand outward, and gradually decrease as the depth increases. The
flux amount decreases gradually from focal point, as shown in Fig. 4.60
To improve the agitation efficiency, we fabricated three kinds of optical
rotors. Figure 4.61 shows the effect of the number of wings of the rotor on
the rotation rate and flux amount. Figure 4.62 shows the relationship between
the average flux amount and rotation rate, with the number of wings as a
parameter. The rotation rate of a three-wingrotor reaches 600 rpm with a
laser power of 200 mW. The average flux amount of a five-wing rotor is 1.15
times greater than that of the three-wing rotor because the five-wing rotor is
in contact with the liquid more frequently, even at the same rotation rate. We
also observed that the higher the rotation rate, the greater the flux amount.
These results show that both the wingnumber and the rotation rate affect
the flux amount.