流体物性对新型并联微通道器内乳化的影响

Influence of Two-phase Flow Physical Properties on Emulsification Using Novel Parallelized Multi-Scale Channels

文中研究了两相流在一种新型并联微通道器内制备单分散性乳液的影响因素.分别以不同物性的油(纯油、质量分数为0.3%的span83、质量分数为0.4%的span83)作为连续相、水作为分散相在微通道内乳化,研究和讨论了流速比、表面张力、毛细管数(Ca)对乳液多分散性和液滴浓度的影响.数值模拟和实验结果表明:16个Y型树枝状并联微通道器不仅可以提供完美的流量分布,而且能够制备优质的单分散性乳液(多分散度Pw≤5.8%),并且其能量消耗率低于35 J/kg;毛细管数对微通道乳化工程有着显著的影响,当Ca≤0.01时,生成的乳液具有更好的单分散性;随着两相流表面张力的升高,乳液单分散性越来越好,但乳液液滴浓度会相应地减小.当表面张力为27.6 m N/m时,水-纯油乳液的Pw为3.0%~5.8%,而水-0.3%span83乳液体系的多分散性值仅为其值的1/2.

In this paper,we study the development of novel multi-scale parallel micro-channel contactor for monodisperse water-in-oil emulsification. Oils with different physical properties（ pure oil,0. 3% span83,0. 4% span83） and water are chosen as a continuous phase and a dispersed phase respectively. By using novel multi-scale contactor（ sixteen parallel Y-type channels） which offers an equal distribution of flow rate with low energy cost（ less than 35 J/kg）,we have studied and discussed the influence of two-phase flow physical properties（ such as flow-rate ratio,surface intension and capillary number） on the emulsion polydispersity experimentally and numerically. Capillary number（ Ca） plays an important role in emulsification progress,and when Ca is less than 0. 01,the mono-disperse emulsion is better. As the surface tension of the two-phase flow increases,the emulsion poly-dispersity is lower and the density of the emulsion reduces. When the surface tension rises to 27. 6 mN/m,the polydispersity（Pw） ranging from 3. 0% to 5. 8% is half of the Pw of water -0. 3% span83 emulsions.