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Bubble coalescence inhibition in volatile solutions at elevated temperatures

“…To verify the effect of surface tension, we can refer to the experimental results of Riberio and Mewes. [4] They reported that as temperature was increased, a higher approaching velocity was required to obtain the shape needed to eventually suppress bubble coalescence for water, which means that the increase of temperature eventually favours coalescence. Considering that decreases in liquid viscosity favour coalescence while decreases in surface tension hinder coalescence, we can conclude that the effect of surface tension on coalescence behaviour is minor compared with viscosity within the scope of the problem we consider.…”

“…Over the last few years, numerous experimental and theoretical studies have been conducted to explore bubble coalescence, and many factors were observed to considerably affect this phenomenon. These factors include physical properties, [4] kinematics, [5][6][7][8] addition of electrolytic salts and organic surfactants, [9][10][11][12][13] approach velocity, [14][15][16] and interfacial mass transfer. [17,18] A recent review of bubble coalescence was given by Liao and Lucas.…”

“…Moreover, as most of the existing studies were carried out at ambient temperatures < 40 8C, the effect of elevated temperatures is virtually unknown. [4] Drogaris and Weiland [10] reported that coalescence time exponentially decreases with rising temperature in the range of 10 T L 60 8C for bubble pairs formed in adjacent capillary tubes in aqueous solutions of n-alcohols and fatty acids. However, Craig et al [20] reported a decrease in bubble coalescence percentage in NaCl and MgSO 2 solutions with increasing temperature through their work with a bubble column.…”

“…However, Craig et al [20] reported a decrease in bubble coalescence percentage in NaCl and MgSO 2 solutions with increasing temperature through their work with a bubble column. Riberio and Mewes [4] recently demonstrated enhancements in bubble coalescence with temperature through their experimental study on bubble coalescence in two different liquids (water and ethanol) at four distinct temperatures (10 T L 40 8C).…”

“…[22] The vapour saturation pressure was determined from the Antoine equation. [22] As discussed by Riberio and Mewes, [4] decreases in liquid viscosity with temperature favour the outward flow of liquid from the bulk of the liquid film. Therefore, this factor suggests a decrease in coalescence time; the slight decrease in the surface tension also somewhat favours dimple formation, which prevents the bulk of the liquid from flowing out of the liquid film.…”