Development of optical digital interferometry for visualizing and modelling the mass diffusion of ammonia in water in an absorption process

Identifier:  imarina:9229552

Handle: https://hdl.handle.net/20.500.11797/imarina9229552

Authors:  Rives, R; Salavera, D; Campos, J; Coronas, A

Abstract:
This study reports the development and implementation of Optical Digital Interferometry for visualizing and modelling mass diffusion in the absorption process of ammonia in water. Absorption experiments were performed at infinite dilution of ammonia and at 293 K, 303 K, and 313 K. The method developed makes it possible to visualize the development of the mass diffusion layer and determine the evolution of concentration profiles in the ammonia/water mixture, providing new spatio-temporal data on the absorption process. A non-equilibrium model based on Fick's Second Law was used to describe the mass diffusion process. It was found that the model can successfully reproduce the experimental profiles of the ammonia concentration. The method developed also allows the simultaneous determination of mass diffusivity and mass transfer coefficients from a single experimental test. The values obtained for the mass diffusivity of ammonia in water vary from 1.54 x 10-9 m2 s-1 at 293.1 K to 2.50 x 10-9 m2 s- 1 at 313.1 K. The relative deviations between the experimental mass diffusivity and literature values did not exceed 6.0%. The mass transfer coefficient ranges from 2.12 x 10-5 m s- 1 at 293.1 K to 4.19 x 10-5 m s- 1 at 313.1 K. The results show the potential of Optical Digital Interferometry for the development and validation of heat and mass transfer models used to design components in absorption refrigeration systems.