关键词: 相间传质, 精馏, 气泡聚并, Marangoni效应, 稳定因子

Abstract: A two-bubble coalescence experimental system was set up to study the effect of interfacial mass transfer on coalescence process of gas bubbles with non-phase change N2 gas phase and volatile aqueous solutions of acetone and ethanol as liquid phase. The coalescence behavior was investigated under different volatile components, concentrations, bubbling frequencies and bubble diameters in the temperature range of 25~50℃. The results showed that because of the Marangoni effect induced by the interfacial mass transfer, the coalescence time decreased at first and then increased with increasing of temperature, the distribution of coalescence time was significantly increased at higher temperatures, and the coalescence percentage was now the best physical magnitude to describe the whole coalescence process. The coalescence percentage began to decrease when the temperature rose to a certain value and tended to be stable at a minimal value at higher temperatures, the minimal coalescence percentage decreased with increasing of aqueous solution concentration, and the intensity of Marangoni effect could be well quantified by the stabilizing index M. Doubling the bubbling frequency and bubble diameter would decrease the minimal coalescence percentage 50% and 67%, respectively.

Key words: interfacial mass transfer, distillation, bubble coalescence, Marangoni effect, stabilizing index