2.3 Study on the morphology and motion of microbubbles under
different parameters
A. Operational parameters. Three operational factors including
pressure, gas-liquid ratio and length of the release pipe were selected
for orthogonal test (3×3) to determine their effects on the particle
size of microbubbles. The specific working conditions are shown in Table
1. The test process is as follows: The microbubble air flotation
equipment was set and operated in turn under 9 kinds of condition
according to Table 1. (1) Start the device. When the liquid level
reaches H=400 mm, the high-speed photography system is started to shoot
the rising process of microbubbles near H=400 mm. Stop flooding when the
liquid level rises to H=450 mm, and the shooting time is 60s. (2) Clean
the device. After one shooting, open the drainage valve at the bottom of
the air floating column to drain the water, and start the device again
to clean the air floating column, so as not to affect the following test
results. The dynamic video was observed, and the particle size of
bubbles was measured and counted. The proportion of bubbles with
particle size ≤50 μm was taken as the experimental index to clarify the
relationship between the main factors and the microbubble particle size
distribution and obtain the optimal working condition.