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.