P. S. Kuts

Unsteady-State Wave Flows of a Gas–Solid Suspension with Gas-Flow-Rate Oscillations and Their Effect on the Heat and Mass Transfer

A set of equations of unsteady-state wave motion of the dispersed phase in a binary vapor–gas medium with allowance for the heat and mass transfer is obtained. By computational experiment, it is studied how gas pulsations at the channel inlet affect the flow of the gas–solid suspension and the intensity of heat and mass transfer under resonant conditions. In particular, it is shown that, in the parameter range studied, gas pulsations enhance the interphase heat and mass transfer.

ON THE PROBLEM OF NONISOTHERMAL MASS TRANSFER IN POROUS MEDIA

We propose a model of nonstationary processes of interrelated heat and mass transfer in porous media that takes into account the mutual influence of vapor and liquid pressures determined by the contribution of the capillary and surface forces and temperature on the interphase mass‐transfer intensity, the thermocapillary flows, and the mechanical and dynamic equilibrium conditions of thin layers of liquids on curved interfaces. The results of the numerical solution of the system of equations of heat and mass transfer in capillary‐porous bodies in discrete and continuous heating as well as with allowance for the effect of nonequilibrium of phase transformations have been analyzed.

Wave Motion of Solid Particles in a Pulsed Gas Flow

The effect of low‐frequency pulsations of gas on the motion of solid particles has been studied on the basis of numerical solution of equations of the dynamics of a monodisperse gas suspension with account for interphase forces of hydrodynamic drag, virtual masses, and forces due to nonstationary effects around particles. It is found that at certain parameters gas pulsations lead to enhancement of interphase heat transfer. The dependences of the time of particle residence in a pneumochannel on the frequency of gas pulsations have been obtained.

Investigation of a pulsating-combustion chamber

The results of experimental investigations of a tangential chamber of pulsating combustion with an aerodynamic valve are discussed. The composition of combustion products, the level of sound pressure, and the temperature field are analyzed.

Modeling of unsteady wave processes in moving media

Using the nonreciprocity relation a difference scheme is built for the wave equation in a moving medium. Examples are given of solution of the problems of sound propagation in the presence of wind.

Hygroscopic properties of biological materials and the binding energy of moisture

The binding energy of moisture with biological materials is determined from sorption isotherms for yeast at different temperatures.

Numerical modeling of nonisothermal moisture transfer in biological colloidal porous materials

The authors derive and substantiate a system of equations of heat and moisture transfer in colloidal capillary-porous undersaturated media with account for the mutual effect of the vapor and liquid pressure, determined by the contribution of surface forces, and the temperature on the rate of interphase mass transfer and the thermocapillary flows. Examples are given of the numerical calculation of evolution of the moisture content and temperature fields and the kinetic dependences in a wide moisture content range for materials of biological origin, namely, yeast, soil. A comparison is made with experimental data.

Investigation of the Hydrodynamics of Vortex Pneumatic Sprayers

Results of experimental investigations of the hydrodynamics of vortex pneumatic sprayers are discussed.

Unsteady wave flows of a gas suspension with account for phase changes

A system of equations of unsteady motion of a gas suspension with account for heat and mass transfer is presented. As a result of the computational experiment, the effect of the gas vibrations at the channel inlet on the motion of the gas suspension and the rate of heat and mass transfer is studied. Specifically, it is shown that, in the considered parametric region, the gas vibrations enhance the interphase heat and mass transfer.

On the critical droplet size in an acoustic field

For Reynolds numbers Re ≪1 an analytical relation is obtained for the dependence of the critical size of a liquid droplet on the amplitude and frequency of a sound field, surface tension, dynamic viscosity of gas with allowance for prehistory of motion and reattachment of mass.