3.1.3 The relationship between microbubble size and its floating
rate
Bubble size was also said to determine the shape and rise pattern of the
bubbles (Edzwald, 2010; Eskanlou et al., 2018).The microbubbles (11.29 ≤
bubble size ≤ 86.19μm, average bubble size = 42.83 μm) generated under
the conditions of pressure of 0.45 MPa, gas-liquid ratio of 5 % and
release pipe of 10 cm were photographed. A single microbubble with
bubble size = 45.19 μm and a combination of two microbubbles with
Db = 65.0 μm (50.97 + 52.19) were selected as targets
for dynamic tracking (948 sec~1009 sec). The target is
shown in Fig.S2. (Note: Db is calculated based on the
total volume of the two small microbubbles, the same below)
The target microbubbles were observed and analyzed during the tracking
period to obtain their acceleration curve (Fig. S3 and S4). Fig.S4(A)
and (B) represent the acceleration of a single microbubble and a
combination of two microbubbles, respectively. The acceleration
detection curve reflects the movement of the target throughout the
tracking period. The positive and negative in the acceleration detection
curve indicate the direction of the acceleration of the target, and the
value indicates the magnitude of its acceleration. By comparing and
analyzing the acceleration of the single microbubble and the target of
the combination, it is found that the acceleration of the two fluctuates
regularly. Whether it is a single microbubble or a combination of two
microbubbles, the magnitude and direction of the acceleration change
throughout the tracking period, which indicates that the resultant force
of the microbubble during the floating process is a variable force, and
the microbubble performs variable acceleration motion.