实时激光全息干涉法测量液相扩散系数

Determination of Liquid Diffusion Coefficient by Real-Time Holographic Interferometer

为研究液相扩散的作用,介绍了一种测量液相扩散系数的激光实时全息干涉系统.利用该系统实时记录液液两相传质的浓度场分布全息图,得到清晰表征浓度场分布的实时全息干涉条纹图;利用全息干涉原理及相应的数学关系处理干涉条纹,得到液相扩散系数.作者首先用已有文献值的KCl水溶液在298.15K下的扩散系数,验证了实验系统的可靠性,在此基础上,进一步测量了坑坏血酸水溶液在298.15K下的液相扩散系数,也进行了测量方法的误差分析.该方法为建立新的液液传质理论提供一定的实验依据,且有利于从微观角度认识液液界面和传质特性.

A real-time holographic interferometer specially designed for measuring diffusion coefficients in transparent mixtures was described with accuracy, promptness and convenience.The principle and method of measurements were also presented in detail.Using this interferometer,the distinct real-time interference fringes indicating the concentration profiles of the liquid were obtained,the liquid diffusion coefficient was simply and directly measured from the interferograms by finite fringe system intentionally introduced to the interferometer.Preliminary results concerning the KCl-water diffusion system at 298.15 K were in reasonable agreement with those of the other methods. Further results obtained for diffusion of L-ascorbic acid in water at 298.15 K were presented and the experimental error of this method was analyzed.The results obtained in this work could provide a good experimental basis for developing a new theory of liquid-liquid mass transfer, and would be helpful to reveal the behavior of liquid-liquid interface and mass transfer.