Coalescence of charged droplets in agitated liquid‐liquid dispersions
Coalescence of charged droplets in agitated liquid‐liquid dispersions
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搅拌的液-液分散体中带电液滴的聚结
DOI：
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发表时间：
1992
期刊：
影响因子：
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通讯作者：
D. Ramkrishna
中科院分区：
文献类型：
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作者：
T. Tobin;D. Ramkrishna
已经进行了实验研究来评估液滴电荷对湍流液滴聚结的影响。尽管众所周知，表面电荷会影响静止介质中布朗粒子的聚结速率，但文献中尚未发现明确研究电荷对湍流介质中较大液滴的影响的研究。
结果表明，液滴电荷可以显着抑制搅拌分散体中液滴之间的聚结。此外，这种效应只能由潜在的液滴电荷产生，这归因于氢氧根离子优先吸附到水-有机相界面上。因此，离子强度和 pH 值在确定搅拌液滴之间的聚结速率方面发挥着重要作用。
结果还表明，依靠平均液滴尺寸的测量来确定聚结速率依赖性是一种不稳定的做法。当结论是基于平均液滴尺寸而不是液滴尺寸分布的测量时，如此处获得的强烈的尺寸依赖性效应有可能得出错误的结论。
Experimental studies have been performed to assess the effect of drop charge on turbulent drop coalescence. Although it is well known that surface charge can affect coalescence rates of Brownian particles in a quiescent medium, no studies have been found in the literature which explicitly examine charge effects on larger drops in turbulent media.
Results demonstate that drop charge can substantially inhibit coalescence between drops in agitated dispersions. Moreover, this effect can arise solely from latent drop charges, which are attributed to the preferential adsorption of hydroxide ions onto the water-organic phase interface. Ionic strength and pH thus are shown to play a major role in determining coalescence rates between agitated drops.
Results also demonstrate that reliance on measurement of average drop sizes for the purpose of determining coalescence rate dependencies is a precarious practice. Strong size-dependent effects such as obtained here have the potential to suggest erroneous conclusions when conclusions are based on measurements of average drop sizes rather than of drop-size distributions.