基于液芯柱透镜测量随浓度变化的液相扩散系数:方法综述

Measurement of concentration-dependent liquid diffusion coefficient based on liquid-core cylindrical lens: Method review

  • 摘要: 液相扩散系数是溶液浓度的函数D(c),通常采用浓度配对法、Boltzmann-Matano(BM)图解法、Hall解析法和多项式数值逼近等方法测量D(c)关联式. 文章在综述以上几种测量方法的基础上,重点介绍了测量D(c)关联式的一种新方法,即BM半解析法. BM半解析法基于液芯柱透镜测量扩散过程中溶液浓度的空时分布函数cexpt(x, t)s,结合Hall解析法以及BM图解法,能够快速、准确、稳定地测量D(c)关联式. 用BM半解析法测量了葡萄糖水溶液在室温下的D(c)关联式,采用时域有限差分法(FDTD)求解Fick扩散方程,计算了不同D(c)关联式下扩散浓度的空时分布函数,计算结果与实验浓度分布函数cexpt(x, t)s进行了分析比较. 结果表明,采用FDTD计算并比较实验扩散浓度空时分布的方法,为实测D(c)关联式的正确性提供了一种有效的判断手段.

     

    Abstract: Liquid diffusion coefficient is a function of the concentration of the diffusion solution D(c), and D(c) correlation is usually measured by concentration pairing method, Boltzmann-Matano(BM) graphical method, Hall's analytical method and polynomial numerical approximation method. After summing up the above measurement methods, this paper mainly introduces a new method for measuring D(c) correlation, that is the BM semi-analytical method. The spatial and temporal profiles of experimental concentration cexpt(x, t)s during diffusion process have been measured on the base of liquid-core cylindrical lenses, combined with the Hall's analytical method and the BM graphical method, the method can quickly, accurately and stably measure D(c) correlation. We measured the D(c) correlation of glucose aqueous solution at room temperature using the BM semi-analytical method. Furthermore, Fick diffusion equation was solved by using the Finite-Difference Time-Domain (FDTD) method, and the spatial and temporal profiles of diffusion concentration under different D(c) correlations were calculated, and the calculated results cFDTD(x, t)s were compared with the cexpt(x, t). The results show that the profiles calculated by FDTD method as comparing with the experimental profile provide an effective verification for the correctness of the measured D(c) correlation.

     

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