The Experimental And Theoretical Studies On Diffusion Coefficients Of The Nutritious Molecules In Non-Newtonian Fluid

Non-Newtonian fluid is often encountered in many fields such as chemical engineering, foodstuff, biology and clinic etc. Strictly, Newtonian fluid is only a special kind of non-Newtonian fluid. Non-Newtonian fluid is closely related to the technology, equipment and efficiency of many industrial processes, as well as the quality of production, moreover, it also virtually involves the life and health of human being, therefore, it is of key significance to study the characteristic and behavior of non-Newtonian fluid, as a result, more and more attention have been paid to it. Amino acids, vitamin and glucose are necessarily nutritious components to every body and have been widely used in clinic treatment and daily life. As well known, the body fluid and blood are typical non-Newtonian fluid, so it is very important to investigate the diffusion of the nutritious molecules in non-Newtonian fluid for controlling the diffused process and helping the clinical treatment. Both polyacrylamide (PAM) and body liquid are pseudoplastic fluid, in this paper, PAM aqueous solution has been used to study the diffusion behavior of the nutritious molecules in non-Newtonian fluid. Viscosity and density are the basic property of the solution. Densities were measured by a pycnometer and viscosities were measured by an Ubbelohde viscometer, and the experimental data were fitted respectively. The apparent molar volumes of the molecules in 0.05% PAM aqueous solution at 298.15K were also calculated, and the results were analyzed and discussed. The diffusivities of amino acids(glynine, arginine, serine, threonine and valine),vitamin(B1, B6 and C) and glucose in PAM aqueous solution and vitamin and glucose in sodium chloride (NaCl) aqueous solution at 298.15K were measured by a real-time holographic interferometer, CCD picture collection and treatment technique. As a contrast, the diffusivities of vitamin and glucose in biologic brine (0.09% NaCl aqueous solution) were measured at 298.15K. On the basis of the existing equation estimating liquid diffusion coefficients of Newtonian fluid at infinite dilution, and combining the rheological equation and the viscosity definition of non-Newtonian fluid, a new model was proposed to predict the liquid diffusion coefficients in non-Newtonian fluid at infinite dilution. According to the equation correlating liquid diffusion coefficients with viscosity, a new correlating equation was developed and applied to calculate the diffusion coefficients of amino acids in PAM aqueous solution at 298.15K, the total average deviation between computed value and experimented data is below 0.6%, which shows a good fitting result.