Chemical Engineering Science, Vol.179, 172-184, 2018
Effects of surface-active agents on bubble growth and detachment from submerged orifice
Present study deals with the effects of surfactants on the dynamics of bubble growth and detachment from a submerged orifice. Experiments are conducted to study the quasi-static growth of air bubble in de-ionized (DI) water mixed with nonionic surfactant Triton X-100. For comparison, bubble growth in pure DI water is also studied. While high-speed imaging is used for flow visualization, instantaneous velocity field, at different stages of bubble growth, are captured via particle image velocimetry. The study also uses bubble pressure Tensiometer technique and Goniometer for measuring the surface tensions. Present investigation shows that the bubble detachment volume decreases with the increase in the surfactant concentration. Further, for low concentration of surfactant, the surface tension gradient influences the flow field significantly and aid the bubble detachment. (C) 2018 Elsevier Ltd. All rights reserved.