Viscosity of a binary fluid in narrow slot-like pores

The concentration dependences of the shear-viscosity coefficient of a fluid, representing a binary mixture of components with molecules of approximately equal sizes, in narrow slot-like pores filled to a different degree (from a rarefied gas to a liquid) have been theoretically investigated with the use of a lattice-gas model accounting for the characteristic volume of atoms and interactions between them in the quasichemical approximation. This model allows one to determine the self-consistent equilibrium characteristics of a vapor-liquid system and the shear-viscosity coefficients of molecules with the use of a unique set of energy parameters. The influence of the activation energy of the surface migration of molecules on the local coefficients of viscosity has been considered. A molecular interpretation of the sliding friction of a fluid near the walls of pores has been given; this effect was explained by the surface migration of the mixture components. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 79, No. 1, pp. 121–132, January–February, 2006.     

Influence of the Evaporation Coefficient and Temperature Jumps on the Thermophoresis of a Moderately Large Volatile High‐Viscosity Sphere in a Binary Gas Mixture with Allowance for Volume Thermodiffusion and Stefan Effects

The theory of a uniform thermophoretic motion of a volatile highviscosity sphere with the phase transition of one component of a moderately rarefied binary gas mixture on its surface has been constructed on the basis of the hydrodynamic method in the regime with slip. The relative influence of the evaporation coefficient and the boundary temperature jumps on the distributions of the velocities, temperatures, and concentrations of the volatile component and the thermophoresis rate has been analyzed. Allowance has been made for the thermodiffusion terms, Stefan effects, and the heat due to the convective transfer of the substance of the condensed phase. The formula obtained has wider limits of application than the existing results. The conclusions of the traditional theories are successfully generalized to the cases of weak and moderately strong processes of diffusion evaporation of a single highviscosity droplet that moves in a nonuniformly heated binary mixture of gases.     

Mechanism of heat and mass transfer during sublimation in a forced flow of rarefied gas

The interaction of a flow of rarefied gas with the flow of vapor close to a surface undergoing sublimation is studied by a visualization method. The rate of sublimation and the intensity of convective heat transfer are expressed as functions of the velocity of the incident flow of rarefied gas.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 20, No. 4, pp. 700–705, April, 1971.     

Transfer properties of mixtures of rarefied neutral gases. Hydrogen–argon system

A method is proposed for generalization of the transport properties of mixtures of rarefied gases on the basis of their particle-interaction potentials and relations of the molecular-kinetic theory. A simultaneous processing of data on the viscosity of a binary Ar–H₂ mixture and its components as well as data on the concentrationdiffusion and thermal-diffusion coefficients of this mixture has been carried out by the weight method. The parameters of three functions of the Lennard-Jones (m–6) potential of interaction between the Ar atoms and H₂ molecules in the indicated mixture were determined. Tables of reference data on the transport properties of the Ar–H₂ mixture at a temperature of 200–2000 K and a concentration x(Ar) varying from 0 to 1 were calculated.     

An Axisymmetric Flow of a Mixture of Real Gases with a Condensing Component

A synthesized physicomathematical model of a binary mixture of real gases with a condensing component is used to perform numerical investigations of axisymmetric flow in nozzles of different geometry. The effect is investigated, which the model of state for gas makes on the position of the “condensation jump”, on the mass spectrum of droplets, and on the flow rate realized by nozzles of preassigned geometry. Comparison of numerical results is made for the Redlich-Kwong and Mendeleev-Clapeyron models and for two sets of components of a binary gas mixture.__________Translated from Teplofizika Vysokikh Temperatur, Vol. 43, No. 3, 2005, pp. 422–430.Original Russian Text Copyright © 2005 by G. V. Molleson, and A. L. Stasenko.     

Flow of a binary gas mixture in a vertical plane-parallel differential-temperature channel

The forced flow of a binary gas mixture in a vertical plane-parallel differential-temperature channel is investigated with allowance for free convection and phase transitions of one of the components of the mixture at the walls of the channel.     

Heat transfer from a spherical source in a rarefied gas

The heat-transfer problem from a sphere in a rarefied gas is solved using a model kinetic equation. Diffuse scattering of gas molecules by the sphere surface with arbitrary energy accomodation is assumed.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 39, No. 3, pp. 428–434, September, 1980.     

The transport properties of an N<Subscript>2</Subscript>-H<Subscript>2</Subscript> mixture of rarefied gases in the EPIDIF database

The principles of organization of the EPIDIF information-and-computation database are considered. Simultaneous processing of experimental data on the viscosity of pure components and mixture and on the coefficients of interdiffusion and thermal diffusion for a binary N₂-H₂ mixture of rarefied gases is performed. Nine parameters of three m-6 Lennard-Jones potentials of interaction of N₂ and H₂ molecules are determined within the least squares method. Tables of reference data for the considered transport properties are calculated in the temperature range from 100 to 1500 K and concentration range of 0–1(0.2). The parameters and their error matrix are included in the EPIDIF database.     

Plane thermal transpiration of a rarefied gas in the presence of gravitation

Plane thermal transpiration of a rarefied gas that flows horizontally in the presence of gravitation is studied based on the Boltzmann equation. Assuming that the temperature gradient along the walls is small, the asymptotic analysis for a slow variation in the flow direction is conducted. The semi-analytical solution that is valid for arbitrary values of the mean free path and the gravitational strength is derived, and the problem is reduced to solving the spatially one-dimensional Boltzmann equation. This reduced problem is solved numerically for a hard-sphere molecular gas for small values of gravitational strength, and the behavior of the flow is studied based on the numerical solution. The effect of weak gravitation is no longer negligible when the gas is so rarefied that the mean free path is comparable to the maximum range that the molecules travel along the parabolic path within the channel. This phenomenon has been observed in the plane Poiseuille flow of a highly rarefied gas, and a similar phenomenon also occurs in the plane thermal transpiration considered in the present paper.     

Mass transfer in a highly rarefied gas

Equations of mass exchange in closed high-vacuum systems are obtained on the basis of the analogy between processes of transfer of molecular particles in a highly rarefied gas and processes of radiation.

     

Calculation of the Boundary Layer of a Two-Phase Medium

Results are given of the calculations of the turbulent boundary layer of a two-phase mixture consisting of a gas and spherical particles 10^–6 m in size. The problem formulation is presented, and the concentration of particles on the wall and the heat flux to the wall are determined. The two-phase mixture is treated as Newtonian liquid, and the gas and solid particles which form this mixture are calculated as continuous flows. The calculation of a two-phase flow in the boundary layer is performed with due regard for the effect of the concentration of solid particles on the viscosity and thermal conductivity of a binary mixture in the presence of the forces of interfacial interaction.     

Isothermal creep of a binary gas mixture along a flat surface

The method of half-space moments [1] is used to derive an analytic expression for the velocity of isothermal creep of a binary gas mixture along a flat surface. The distribution functions for the gas molecules are found from the solution of the Boltzmann kinetic equation with a model collision integral.     

Heat exchange in the flow of a hypersonic rarefied gas stream over a blunt wedge

The cooling of the leading edge of a blunt wedge over which a hypersonic rarefied gas stream flows is studied.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 28, No. 5, pp. 788–792, May, 1975.     

Boundary conditions at a surface undergoing sublimation into a rarefied multicomponent gas

Boundary conditions have been found for flow of a rarefied multicomponent gas over a sublimating wall. For a multi-component gas the boundary conditions obtained are a generalization of the wellknown conditions for slip and temperature jump in the case of a permeable surface.     

Effect of the rate of a homogeneous chemical reaction on the temperature and concentration distribution in the boundary layer of a turbulent gas flow in a circular tube

The authors examine a simplified model of a flowing binary gas mixture reacting at a finite rate. The factors determining the temperature distribution in the wall region are analyzed.     

On the temperature jump in a rarefied gas over a permeable surface

An expression is obtained for the temperature jump in a rarefied gas over a permeable surface on the basis of a numerical solution of the model kinetic equation in the Knudsen layer.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol.19, No.2, pp. 259–264, August, 1970.     

Formulation of the boundary conditions on curvilinear surfaces streamlined by a rarefied gas

The necessity of taking into account the Barnett correction to the gas distribution function in the boundary conditions on curvilinear surfaces streamlined by a rarefied gas is demonstrated for a solid sphere.     

Transfer of heterogeneous droplets in the field of a temperature gradient

The thermophoresis of a double-layer moderately large volatile droplet with a solid core, placed in a binary viscous gas mixture, is considered The thermodiffusion within the volume of a two-component gas mixture is allowed for, and all corrections for the Knudsen number are taken into, account completely. An equation for the thermophoresis rate is derived, and a full analysis of the velocity of a large particle as a function of its radius and the core radius is given.N. K. Krupskaya Moscow Regional Pedagogical Institute. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 65, No. 2, pp. 235–242, August, 1993.     

On the problem of calculating the velocity of a rarefied gas sliding round a solid cylindrical surface

The velocity of a rarefied gas sliding round a right circular cylinder surface is calculated using exact analytical methods. The results are compared to the other published data.     

Thermodiffusiophoretic capture of aerosol particles in a plane channel with nonuniform temperature

The article theoretically studies the process of capturing aerosol particles from a laminar stream of a binary gas mixture inhomogeneous in temperature and concentration passing through a plane channel with nonuniform temperature.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 41, No. 1, pp. 47–54, July, 1981.