数字全息法测量液相扩散系数实验研究

Diffusivity Measurement of Liquid Solutions by Real-Time Digital Holography

采用数字全息干涉法测量了25℃乙二醇-水物系的扩散系数。详细介绍了实验方法以及2种处理干涉图像获得扩散系数的方法,即横条纹法和弯条纹法。通过测量25℃时0.33 mol/L KCl溶液的扩散验证了实验的精确性。分别用2种方法获得了6个不同质量分数下的乙二醇-水物系的扩散系数,并与文献值进行了对比。结果表明,弯曲条纹法的平均相对偏差是1.3%,比水平条纹法的1.7%小,同时,弯曲条纹法的平均标准偏差更小,说明波动更小。

Real-Time digital holography is used to measure the diffusivities of ethylene glycol-water system at 25 ℃. The experimental technique and two methods based on horizontal and curved fringes for processing holographic image data are presented in detail. 0. 33 mol·L^-1 aqueous solution of potassium chloride at 25 ℃ was used as a reference system to check the two methods. Compared with literature data,the results show that both methods are reliable with good accuracy. Measurements are conducted at 6 concentrations of the ethylene glycol-water system and the results of both methods are also compared with the reported data. The average relative deviation of the curved fringe method is 1. 3%,slightly superior to that of the horizontal fringes method. Moreover,diffusivities calculated by the two methods fluctuate with the choice of time. A comparison of the standard deviations of the two methods shows that the curved fringe method is more stable than the horizontal fringe method.