2015 年 81 巻 823 号 p. 14-00612
The motion of a bubble rising in sodium acrylate polymer (SAP) solutions is experimentally explored. In this study, 0.3 and 0.6 wt% SAP solutions with shear-thinning and elastic properties are prepared. The bubble rise motion depending on the value of the suspending viscosity is examined covering from small to large-sized bubbles. Consequently, it is confirmed that bubbles rising in the SAP solutions have cusped shapes due to the elastic effect except for large deformed bubbles in the 0.6 wt% SAP solution. In addition, the bubble rise motion in the viscoelastic liquid is considered and discussed based on effective physical parameters and the terminal bubble rise velocity. In the experiment using the 0.6 wt% SAP solution, it is observed that a jump discontinuity of the terminal bubble rise velocity has occurred. It is verified that the velocity jump in this study doesn't arise from the change in the bubble shape caused by the elastic effect. It is shown that effective Reynolds and Morton numbers allow us to systematically organize the bubble rise motion in the viscoelastic liquid with taking the shear-thinning effect into account. One can reasonably analyze viscoelastic bubble morphology by applying effective Reynolds and Morton numbers and Deborah number to a viscoelastic non-Newtonian system.
