Experiments were conducted on the variations of shape and velocity of single bubbles during rising in three types of surfactant solutions with different concentration in order to effectively modulate the behavior of meso-scale bubbles in bubbly flow. Single bubbles with the size of 1.3-6 mm were generated in a square glass column
and the instantaneous motion of single bubbles was recorded using a high-speed camera. Then bubble shape and velocity were determined from the recorded frames using the image analysis software. The results show that the right concentration of surfactants used here would dampen bubble deformation
reduce shape oscillation amplitude and slow down the bubble rise velocity significantly due to the Marangoni effect. The addition of 0.15 mmol/L Triton X-100 would reduce the oscillation amplitude of the bubble aspect ratio by 57% while the addition of 0.05 mmol/L Triton X-100 would lower the terminal velocity of bubbles by 35% compared with those in pure water. Moreover
The bubble shape oscillation would influence the bubble transient velocity. It seems that under the present experimental conditions
the modulation effect of the addition of different types of surfactants on meso-scale bubble behavior is quite different. The addition of Triton X-100 has stronger effect on the modulation than the addition of Polyethylene glycol or n-Pentanol.
关键词
Keywords
references
KULKARNI A A, JOSHI J B. Bubble formation and bubble rise velocity in gas-liquid systems: a review [J]. Industrial and Engineering Chemistry Research, 2005, 44(16): 5873-5931.
CLIFT R, GRACE J R, WEBER M E. Bubbles, drops, and particles [M]. 2nd ed. New York, USA: Academic Press, 2005.
TSUKADA T. The effect of EHD convection on motion of a bubble under microgravity [J]. Journal of Chemical Engineering, 1995, 28(6): 810-815.
ELLENBERGER J, KRISHNA R. Levitation of air bubbles in liquid under low frequency vibration excitement[J].Chemical Engineering Science, 2007, 62(18): 5669-5673.
CUI Zhe, LI Yanpeng, GE Yang, et al. Bubble modulation using acoustic standing waves in a bubbling system [J]. Chemical Engineering Science, 2005, 60(22): 5971-5981.
李彦鹏,FAN L S.鼓泡塔中驻波声场调制大气泡的直接模拟 [J].应用基础与工程科学学报, 2007, 15(2): 217-225.
LI Yanpeng, FAN L S. Direct simulation of a large bubble modulation with an acoustic standing wave in a bubble column [J]. Journal of Basic Science and Engineering, 2007, 15(2): 217-225.
FINCH J A, NESSET J E, ACUNA C. Role of frother on bubble production and behavior in flotation [J]. Minerals Engineering, 2008, 21(12/13/14):949-957.
KRACHT W, FINCH J A. Effect of frother on initial bubble shape and velocity [J]. International Journal of Mineral Processing, 2010, 94(3/4):115-120.
KRZAN M, ZAWALA J, MALYSA K. Development of steady state adsorption distribution over interface of a bubble rising in solutions of n-alkanols and n-alkyltrimethylammonium bromides[J]. Colloids and Surfaces: A Physicochem Eng Aspects, 2007, 298(1/2):42-51.
TAKAGI S, OGASAWARA T, MATSUMOTO Y. The effect of surfactant on the multiscale structure of bubbly flows [J]. Philosophical Transactions of the Royal Society: A, 2008, 366(3):2117-2129.
DU Jianwei, TANG Cuiping, FAN Shuanshi, et al. Experimental investigation on Span20 promoting effect on methane hydrate formation [J]. Journal of Xi'an Jiaotong University, 2008, 42(9): 1165-1168.
WANG Huanran, LI Yanpeng, YANG Dong, et al. On the shape feature of a single bubble rising in viscous liquids [J]. Journal of Engineering Thermophysics, 2009, 30(9): 1492-1494.
HE Dan, LI Yanpeng, LIU Yanyan. Effect of initial bubble shape on the dynamics of a buoyancy-driven bubble [J]. Journal of Xi'an Jiaotong University, 2011, 45(1): 6-10.