Platform and method for rapidly measuring liquid phase diffusion coefficient as function of solution concentration

Abstract

The invention relates to a platform and a method for rapidly measuring a liquid phase diffusion coefficient D(C) as a function of concentration (C). The core element of the platform is a liquid core cylindrical lens. The liquid core region is a diffusion cell. Lens parameters are selected to reduce the spherical aberration and improve the detection sensitivity of the liquid concentration. A monochromatic collimated light beam forms a dynamic diffusion image on the focal plane thereof after passing through the liquid core cylindrical lens. The method comprises the following steps of: obtainingan experimental concentration distribution function C<e>(x<j>,t<0>) along a diffusion direction according to the diffusion image at time t<0>; solving a diffusion equation by using the diffusion coefficient D<0> under an infinite lean condition as a boundary condition; expanding the D(C) to D(C)=D<0>(1+alpha<1>xC+alpha<2>xC<2>+alpha<3>xC<3>+...); obtaining a calculating concentration distributionfunction C<n>(x<j>,t<0>) at the same moment as C<e>(x<j>,t<0>) after pre-setting a pending coefficient(alpha<1>, alpha<2>, alpha<3>...); comparing C<e>(x<j>,t<0>) and C<n>(x<j>,t<0>); determining D(C)value according to the coefficients [(alpha<1>)<best>, (alpha<2>)<best>, (alpha<3>)<best>] corresponding to the minimum value of the minimum standard deviation between C<e>(x<j>,t<0>) and C<n>(x<j>,t<0>); calculating the concentration distribution C<n>(x<j>,t) at any time (t is not equal to t<0>) according to D(C) and a ray tracing method, and simulating the diffused image; and comparing the experimental and the simulated image to verify the D(C) relationship.

Description

technical field [0001] The invention belongs to the method for measuring the liquid phase diffusion coefficient changing with the concentration in the liquid phase mass transfer technology. Background technique [0002] Liquid phase diffusion coefficient is an important basic data for studying mass transfer process, calculating mass transfer rate and chemical design and development. It is widely used in emerging industries such as biology, chemical industry, medicine and environmental protection. In general, the liquid-phase diffusion coefficient is a function of solution concentration and varies with the concentration of the diffusing solution. There are multiple measurement methods for the liquid phase diffusion coefficient, among which, the membrane cell method (Stoke R.H., An improved diaphragm-cell for diffusion studies, and some tests of the method, J.Am.Chem.Soc., 72:763-767 (1950 )), Light Interferometry (Zhao Changwei, Li Jiding, Ma Peisheng, Xia Shuqian, Measureme...

AI Technical Summary

Problems solved by technology

Obviously, the traditional measurement methods have problems such as complicated devices, insufficient stability, and poor result accuracy; the measurement of the liquid-phase diffusion coefficient that varies with concentration has the problems of long time-consuming and heavy workload.

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