A New Method of Processing Mach–Zehnder Interference Fringe Data in Determination of Diffusion Coefficient

Abstract

Laser holographic interferometry is the newest method to measure the mass diffusion coefficient and has been widely used in recent years. The processing of interference fringe images is a critical step of getting the final precise experimental results. On the basis of Fourier transformation and phase measurements, a new method of processing Mach-Zehnder interference fringes is introduced in this article. By experimental verification and uncertainty analysis, the accuracy of this method is validated. Mass diffusion coefficients of ethylene glycol dimethyl ether and diethylene glycol dimethyl ether, two new fuel additives in air were measured with the method introduced in this study.

Determination of Binary Gas Diffusion Coefficients Using Digital Holographic Interferometry

“…The basic theory of the experiment is Fick’s second law of one-dimension diffusion, which can be written as ∂ c ∂ t = D AB ∂ 2 c ∂ z 2 The final equation for calculating D AB can be deduced as D AB = Δ z m 2 t 1 / t 2 − 1 8 t 1 ln ( t 1 / t 2 ) where D AB is the binary diffusion coefficient, t 1 and t 2 are the moments of collecting the interference fringes which may be read from the computer timer, and Δ z m is the vertical distance between the two extreme points of the solution’s concentration difference which can be extracted from the interference fringe image by image processing methods. The detailed experimental theory and interference fringe processing method have been described previously …”

“…On the basis of our previous work, ,, a holographic interferometric experimental system for measuring the binary gas diffusion coefficient was used. A diffusion cell was designed and constructed to achieve the process of gas diffusion.…”

“…It is a widely used experimental method for measuring thermophysical properties of fluids and has been used by many researchers to measure the diffusion coefficient of liquids; its accuracy and reliability have been verified. 8,9 On the basis of our previous work, 11,12,14 a holographic interferometric experimental system for measuring the binary gas diffusion coefficient was used. A diffusion cell was designed and constructed to achieve the process of gas diffusion.…”

Electromigration diffusivity spectrometry: A way for simultaneous determination of diffusion coefficients from mixed samples

“…They are simple but commonly slow and not suitable for measuring analytes with very limited sample volume. Optical approaches were later explored and formed the biggest methodological family, including Gouy fringe pattern [17,18], Rayleigh fringe pattern [19,20], Mach-Zehnder fringe pattern [21], holographic measurement [22,23] and light scattering [24][25][26], and so forth [27]. Optical methods often require very fine setups, which are not always available for use.…”