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The results of numerical studies of energy separation of a helium-xenon gas mixture in a single Leontiev tube with a central cylindrical channel are presented. On the basis of the simulation data, a T-s diagram for energy separation is constructed. The changes in the total temperature depending on the entropy change in the central subsonic channel and in the annular supersonic nozzle are shown.

The results of numerical studies of heat and mass transfer during adiabatic evaporation of an aqueous solution of ethanol into an accelerated steam-air laminar boundary layer on a flat wetted plate are presented. The flow acceleration is realized due to the inclination of the upper channel wall, which ensures the constancy of the Kays acceleration parameter. The dependences of the evaporation intensity of the components of solutions of various compositions are obtained for the acceleration parameter 0 and 10-6 for the flow temperature from 20 to 50 °C. A significant effect of the accelerating pressure gradient on the evaporation intensity and its weak effect on the equilibrium wall temperature are shown.

The results of studies of heat and mass transfer during adiabatic evaporation of binary liquids of water/ethanol and water/acetone into a turbulent boundary layer of a vapor-air mixture from a flat wetted plate are presented. The dependences are obtained for the evaporation intensity of solutions of various compositions on the temperature of the air flow or the equilibrium superheated steam into which the liquids evaporate. The inversion temperature values for liquids with different concentration of the volatile component are determined. The effect of flow turbulence on the evaporation rate and inversion temperature is analyzed.

The redistribution of the total temperature between the parts of the gas stream flowing through the Leontiev tube depends not only on the temperature recovery factor (Prandtl number) and the ratio of flows through the supersonic and subsonic channels of the tube (Mach numbers), but also on the thermal resistance of the separation wall. Earlier it has been shown that the reduction of thermal resistance due to the separation wall finning on the side of the subsonic flow leads to an increase in the efficiency of energy separation. It may be assumed that the intensification of heat exchange between channels, due to finning, reduces the length of the tube, which at the same intensity of heat exchange leads to a decrease in pressure losses and an additional increase in efficiency. This paper presents the results of numerical simulation of energy separation in Leontiev tubes with a finned separation wall and different lengths of supersonic nozzle. It is shown that the adiabatic efficiency of the energy separation in a short Leontiev tube with a finned wall increases when the outlet pressure decreases, while it does not change for smooth tubes.

The results of the analysis of the problem of wetting the microstructured flat wall surface during adiabatic liquid evaporation into a boundary layer of air flowing at right angles are presented. The basic conservation laws are formulated in the form of differential equations that allow calculating the velocity and height of liquid rise in capillaries, wetting dynamics, depth and mass of the liquid in capillaries, and the evaporation surface area.

The paper presents results of numerical simulation of energy separation (temperature stratification) of helium-xenon gas mixture with low-Prandtl number, flowing in the finned single Leontiev tube. Only the inner surface of the central channel for subsonic part of the flow was finned by longitudinal fins. The influence of the flow rate of the cooling gas, flowing through the central channel, on the energy separation efficiency was analyzed in comparison with the efficiency of Leontiev tube with smooth walls. The method of efficiency enhancement by insulating the low-temperature area at the tube outlet was suggested.

A stationary flow of three-component gas in a laminar boundary layer on a flat plate is considered at adiabatic evaporation of a two-component liquid film. Numerical modelling were carried out at atmospheric pressure, air flow velocity of 2 m/s and temperature from 20 to 500 °C in the whole range of concentrations of a low-boiling component of binary solutions: ethanol/water, acetone/water, and acetone/ethanol. Data on the local specific evaporation rate of ethanol/water and acetone/water solutions into dry air and superheated mixture of ethanol, acetone and water vapors were obtained depending on the temperature of the inlet flow. Composition of superheated vapor mixture was taken to be equilibrium relative to the liquid solution. With an increase in the molar fraction of ethanol or acetone in the water solution, the evaporation rate increases, and when evaporated into superheated vapor, the growth of evaporation rate with increasing vapor temperature is significantly higher than at evaporation into air. With an increase in ethanol or acetone concentration in the liquid solution, the inversion temperature decreases from down to 155…165°C.

The paper presents the results of numerical simulation of nonstationary sublimation of spherical particles of Cr(acac)3, floating in the volume of a binary mixture (argonsuperheated vapor of precursor) in a reactor with hot walls. The influence of the vapor content, reactor wall temperature and radiative heat transfer on the kinetics of sublimation/desublimation are analyzed. The characteristic times of induction and total sublimation, as well as the intensity of mass entrainment from the surface of particles of different sizes are determined. The influence of radiation from the hot walls of the sublimator on these parameters is determined.

The vortex chambers are the widespread equipment in energy, chemical and mining industries. The upgrade of existing equipment and development of new models of vortex chambers require the detail analysis of swirling flow structure. This paper presents results of numerical modeling of the airflow dynamic in a vortex chamber with the outlet diaphragm and side slot swirler. The main attention is paid to the end boundary layers and to their influence on the flowage of vortex chambers. The study has been done for a wide range of swirl angles with Reynolds numbers of up to 1720.

This paper presents results of numerical modeling of energy separation for helium- xenon gas mixture flow in a two-cascade Leontiev tube with central and outer (annular) supersonic nozzles. The Mach number and stagnation temperature distributions in longitudinal section and the heat-transfer intensity from the subsonic to supersonic flow have been obtained. The dependences of the cooling effect, the temperature efficiency factor and the adiabatic efficiency on a stagnation pressure in the receiver have been investigated.