V. V. Dil'man

Combined method for studying and calculating the multicomponent diffusion in a mixture with an inert gas

A combined method for calculating the diffusion for a mixture with an inert gas in which the molar flux of the latter is equal to zero is considered. The method is based on using only one of three Stefan-Maxwell equations, the equation for the inert gas. This equation is reduced to a linear ordinary differential equation of the first order, which has a simple solution. The equations for the inert gas are closed using the modified Fick’s first law. The method makes it possible to radically simplify the study and calculation of multicomponent diffusion. Comparison with the experimental data taken from the literature showed that the deviation of the calculated curves from experimental points for a ternary mixture is within the experimental error.

Nonlocal Models of Turbulent Transfer

Turbulent transfer is considered with regard for the fact that the velocity of turbulent pulsations is finite. Nonlocal turbulent-transfer models describing the initial stage of turbulent mixing of nonreactive and reactive flows (including turbulent premixed combustion) are analyzed, as well as models of heat and mass transfer to the solid surface in turbulent boundary layers.

Kinetics of Unsteady Evaporation during Liquid-Phase Transesterification

The kinetics of unsteady evaporation during liquid-phase transesterification is studied theoretically and experimentally. A mathematical model of the process is proposed, and a satisfactory agreement between the calculated and observed data is demonstrated.

The Rate of Unsteady-State Evaporation of a Quiescent Liquid Layer in the Open and Closed Systems

The influence of natural convection on the unsteady-state evaporation rate is analyzed theoretically on the basis of Ficks law. The observed and calculated data for propyl acetate, propyl formate, methyl acetate, and methyl formate evaporation in nitrogen are in satisfactory agreement.

Dynamics of Unsteady-State Evaporation of Binary Mixtures in Closed Systems

The rate of unsteady-state evaporation of a stagnant layer of methanol–water, formic acid–water, ethanol–isopropanol, methanol–ethanol, and methanol–isopropanol binary solutions into an inert gas (helium or argon) is studied in a closed system. The ratio between the molecular weights of the components in a gas–liquid system is shown to have a substantial effect on the process kinetics. For the first time, a synergetic interaction between the components during unsteady-state mass transfer is observed. The experimental data satisfactorily agree with the calculated results.

Dynamics of Unsteady-State Distillation Combined with Transesterification in the Liquid Phase

The kinetics of unsteady-state distillation combined with the catalytic transesterification of butyl acetate with ethanol is studied experimentally and theoretically. Experiments were carried out in the film column at total reflux. A mathematical study of the reactive distillation process is carried out using a cell model. The calculated and observed data are in satisfactory agreement.