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题名	表面活性剂对液液体系传质Marangoni效应的影响
作者	王智慧
学位类别	博士
答辩日期	2011-06-02
授予单位	中国科学院研究生院
导师	杨超
关键词	Marangoni效应 传质 表面活性剂 数值模拟 水平集方法
其他题名	Effect of surfactants on Marangoni effect induced by mass transfer in liquid-liquid systems
学位专业	化学工程
中文摘要	多相传递广泛存在于自然界以及工程技术领域，在石化、制药、冶金等化工领域发挥着重要作用。当相间传热或传质发生时，界面上热或质的分布不均将形成界面张力梯度，由相界面的界面张力梯度引起的界面流动及伴随的不稳定性统称为Marangoni效应。研究表明Marangoni效应可以有效促进传热或传质，甚至可以使传质系数增大一个数量级。因此深入了解Marangoni 效应的的作用机理及调控方法，可以为传递过程的强化提供参考。本文建立了纹影观测装置，通过直接观测和传质实验考察了溶质浓度对液滴生成及静置阶段的Marangoni效应及传质效率的影响，分别将静置阶段和生成阶段的液滴萃取分数与Marangoni数相关联，得出了萃取分数与Ma数的非线性经验关联式。进一步考察了不同离子类型的表面活性剂在不同浓度下对界面Marangoni效应的影响，结合表面活性剂分子与溶质间的界面能垒效应，分析了表面活性剂对溶质相间传质的影响。建立了平界面两液层的传质实验装置，分析了溶质浓度、流速、流动方向及表面活性剂对Marangoni效应及传质的影响。在Mao等建立的两液层流体运动及相间传质的数学模型的基础上，加入表面活性剂体相传质及界面吸附动力学方程，模拟了含表面活性剂体系中的界面Marangoni效应及相间传质过程，模拟结果与实验结果符合较好。结合连续表面力思想，利用浓度变换方法，推导出连续界面源方法，以水平集函数捕捉界面，在欧拉网格下建立了两相均可溶表面活性剂的体相传质与界面对流吸附相耦合的数学模型，在二维轴对称的柱坐标系中建立了液滴不断生长的非稳态运动过程中萃取传质的数值模拟方法，数值模拟结果与实验吻合较好。
英文摘要	Transport phenomena, broadly existing in the nature, engineering and technology, play an important role in chemical industry, such as petrochemical, pharmaceutical and metallurgical industries. With mass or heat transfer taking place in multiphase systems, the non-uniform distributions of components or temperature at the interface would form interfacial tension gradient, hereafter the interfacial convection or instability might be developed, which is called Marangoni effect. Many research results indicated that Marangoni effect can enhance mass or heat transfer effectively, even promote the mass transfer coefficient in the order of higher than a magnitude. The experimental and theoretical studies on the Marangoni effect induced by mass transfer are very valuable to the theory and application of chemical engineering disciplines. To observe Marangoni convection directly, a Schlieren optical system was constructed. Combined with the mass transfer measurement in the processes of drop formation or a drop hanging on the needle, solute concentrations and formation velocities were used to test the impact of Marangoni effect on experimental mass transfer coefficients. Based on experimental data and other reports, the prediction models with Ma numbers of extraction fractions for a hanging drop and drop formation were obtained. Furthermore, to investigate the influence of surfactants on Marangoni effect, a cationic surfactant of DTAB (Dodecyl Trimethyl Ammonium Bromide), an anionic surfactant of SDS (Sodium dodecyl sulfate) and a nonionic surfactant of Triton X-100 were added into the aqueous phase of liquid-liquid systems respectively. Combined with the molecular effect, the effect of surfactants on interpahse mass transfer was analyzed. The interphase mass transfer between two planar layers of immiscible liquids and Marangoni effect were also investigated. The impacts of solute concentration, velocity and surfactant concentration were tested. The model of surfactant bulk transportation and adsorption/desorption dynamics equation at the interface were built up, embedded in Mao’s numerical model of mass transfer and Marangoni effect in two planar liquid-liquid layers. The Marangoni effect and mass transfer for the liquid-liquid system with a surfactant were simulated. The simulation results are in good agreement with our experimental data, verifying the present model and method are correct and reliable. Inspired by the well-known CSF (continuum surface force) method and the concentration transformation method, the continuum mass source method was developed to simulate the transportation of soluble surfactants in the framework of the level set method for capturing interface. The Marangoni effect and interphase mass transfer of a single drop formed in an aqueous solution of a surfactant were simulated. The predicted results also fit well with the experimental data.
语种	中文
公开日期	2013-09-23
页码	211
内容类型	学位论文
源URL	[http://ir.ipe.ac.cn/handle/122111/1676]
专题	过程工程研究所_研究所（批量导入）
推荐引用方式 GB/T 7714	王智慧. 表面活性剂对液液体系传质Marangoni效应的影响[D]. 中国科学院研究生院. 2011.

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