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162 4 Optical Rotor
Rotation rate (rpm)
140 310

3
Wing number 100 mms -1

5

Fig. 4.61. Velocity vectors for rotors with different numbers of wings, with rotation
rate as a parameter

120
Flux amount (mm s -1 ) 80 5 Wings 3 Wings
100
3 Wings
60
40
20
0
0 100 200 300 400 500 600
Rotation rate (rpm)
Fig. 4.62. Flux amount generated by shuttlecock optical rotors with different wing
numbers

In summary, three kinds of optical rotors are proposed stirringthe liquid
around them, and the characteristics that promote mixingare confirmed. The
fluidic velocity vectors around the 20-µm-diameter SU-8 rotors are visualized,
and the flux amounts are derived at different depths both theoretically and
experimentally.
The microflow arises within two to three times the rotor diameter and
thickness for the horizontal rotation, and the flow goes not only outward but
also up and down. The average flux amount gradually decreases as the depth
increases. The flux amount of the five-wingrotor is 1.15 times greater than
that of the three-wingrotor at the same rotation rate. The velocity vectors of
the vertical rotation originate from the left wing and flow into the right wing
and expand outward partly alongthe optical axis, which promotes convective
mixing.