Study on the Gas-Liquid Interfacial Turbulence Phenomena

在传质过程中，由于物质的传递使界面处物质的物理化学性质发生变化，在界面处可能会引起流体宏观流动，这种现象即为界面湍动现象。引起界面湍动现象的原因主要可归结为表面张力梯度引起的Marangoni效应和密度梯度引起的Rayleigh效应，粘度等其它因素则会影响界面对流作用的强弱。界面现象的产生，不但会促进液体的表面更新，而且还会增强溶质对液相主体的渗透，对传质有着极大的促进作用，研究界面湍动现象对促进界面传质机理的理解具有非常重要的意义。 观察界面湍动现象的方法一般有示踪法、粒子成像测速法（PIV）、激光干涉法、纹影法和投影法等，本文通过采用激光投影法对界面现象进行垂直方向的观察，利用N2吹扫气...During the process of gas-liquid mass transfer, the interface turbulence phenomena could occur near the interface if the density and surface tension of the fluid near the interface change due to the mass transfer. With respect to different mechanism, the Marangoni convection is caused by the surface tension gradient and the Rayleigh convection is caused by the density gradient. The other chemical ...学位：工学硕士院系专业：化学化工学院化学工程与生物工程系_化学工程学号：2062007115088

Observation on Marangoni convection induced by desorption in falling soap film

In gas-liquid mass transfer processes,Marangoni convection may occur due to the surface tension gradient produced by mass transfer near the interface.With a falling soap film tunnel and the Schlieren optical method,the Marangoni convection patterns along the film surface were observed directly in the desorption process of acetone from the falling soap film.The Schlieren images showed the regular roll convection in the thin falling soap film during the acetone desorption.The hydraulic characteristics were determined experimentally by measuring the variation of acetone concentration in the film and the surface tension of the soap liquid.The results show that the acetone concentration gradient vertical to the falling direction is very small because the thickness of the soap film is in the order of 10-6 m.The variation of acetone concentration along the falling film is large,so there is a significant surface tension gradient,resulting in the Marangoni roll convection.The experimental results and a qualitative analysis may be helpful to understand the mechanism of Marangoni convection near the interface in the mass transfer.国家自然科学基金项目(20606027)---

Numerical Simulation of the Marangoni Convection

通过对有机溶液在水表面溶解引发的MArAngOnI对流进行数值计算,表明表面张力变化导致的MArAngOnI对流在临近界面区域具有显著的强度和速度梯度,但在液相主体区域流速较低,模拟得到的最大表面速度数值及表面速度分布符合文献报道同条件下的实验结果.根据数值模拟得到的流场结果分析表明,MArAngOnI对流只是在近界面区域有着较高的界面流速,MArAngOnI对流对传质的影响主要是加速了表面更新,导致了较高的传质速率.Numerical simulation was carried out to investigate the Marangoni convection which was induced by deposition of the surface tension-lowering organic solution on the water interface.Results from the simulation show that the Marangoni convection induced by the surface tension gradient has the significant intensity and the sharp velocity gradient near the interface.However the horizontal velocity component in the most of bulk of water is much lower than that near the interface.Both the maximum interface velocity and the distribution of the interface velocity are consistent with the published experimental measurement.According to numerical results,the influence of the Marangoni convection on mass transfer is contributed to acceleration of the surface renewal and enhancement of mass transfer due to the high velocity induced by Marangoni convection near the interface.国家自然科学基金(20606027));福建省自然科学基金(2006J0266)资

杭州西湖浮游藻类变化规律与水质的关系

于2006～2007年对杭州西湖浮游藻类的种类及个体丰度进行初步研究,并依据《水和废水监测分析方法》对其水质现状进行了生物学评价。综合生物和理化指标数据,对杭州西湖的水质作一总体评估,并对西湖水中的物种多样性保护及水质的可持续利用提出了建议。共鉴定浮游藻类179种,其中蓝藻25种,隐藻1种,金藻3种,甲藻3种,黄藻5种,裸藻23种,硅藻41种和绿藻78种。分析了杭州西湖浮游藻类的组成和分布的特点,揭示出西湖浮游藻类的种类组成与西湖水质变化之间的关系。结果表明：藻类的组成和分布与水质变化规律基本吻合,西湖水质较整治前有明显的改善,一些清水藻类的物种逐步增多