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.     

Heat transfer in plane Couette flow of a rarefied gas

Summary In this paper Shen's method is used for solving the problem of heat transfer in plane Couette flow of a rarefied gas. An approximate distribution function is assumed and the appropriate transfer equations, which exhibit the proper collision effect between the molecules, are used to determine the temperature jumps at the plates.     

Mass transfer from a single gas slug

The process of mass transfer from a single gas slug to the liquid is investigated experimentally and theoretically. The mass transfer and hydrodynamics of flow over a slug are represented visually.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 48, No. 4, pp. 533–538, April, 1985.     

Investigation of heat and mass transfer in a rarefied gas using high-frequency measurement techniques

Devices based on a high-frequency generator for investigating heat and mass transfer in a rarefied gas — solid system are described. Their fundamental characteristics are given and procedures and results of tests are presented. __________ Translated from Izmeteritel’naya Tekhnika, No. 3, pp. 49–54, March, 2006.     

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.     

Couette problem for a rarefied gas in a channel

A study is made of the influence of the accommodation coefficients of tangential momentum of molecules on the lower and upper plates on the behavior of the gas between moving plates with arbitrary mirror-diffuse boundary conditions. The solution is constructed in a wide range of Knudsen numbers. Expressions for the mass and heat fluxes, the friction force, and the mass velocity are obtained. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 79, No. 2, pp. 186–193, March–April, 2006.     

Effect of mass transfer on the process of heat transfer with sublimation in a rarefied gas medium for couette flow

The effect of transverse mass flow on heat transfer has been determined for the case of sublimation of a moving plate in a rarefied gas medium. It has been established that at Knudsen numbers Kn>0. 001 it is necessary to take into account the effect of the wall layer near the subliming surface.     

Benchmark problems in rarefied gas dynamics

In order to identify the most efficient and reliable methods and solvers for modeling of rarefied gas flows, it is proposed to choose few benchmark problems to be solved by different methods. The main requirements to such problems, such as geometrical simplicity and small number of determining parameters, are formulated in the present work. Two benchmark problems are proposed. A comparison between numerical and experimental data of these problems available in the open literature is performed.     

Experimental study of heat exchange in a moderately rarefied gas

An experimental study is performed of heat exchange in multiatomic gases at moderate Knudsen numbers in coaxial geometry. The data obtained are described well by the Liu-Lees theory of multiatomic gases.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 49, No. 4, pp. 579–585, October, 1985.     

Mass transfer in porous injection of an inert gas into a liquid

Measurements are reported on mass-transfer coefficients for a liquid containing a porous body through which an inert gas is injected. The data are compared with measurements on heat transfer on porous injection and on boiling.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 51, No. 3, pp. 410–414, September, 1986.     

Mass transfer between the gas and solid particles in a fluidized bed

A model of the boundary layer and condition of suspension of a solid particle by a gas flow is used to formulate analytical correlations, which are then compared with experiment.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 41, No. 6, pp. 1067–1072, December, 1981.     

Nonisothermal flow of a rarefied gas in a circular cylindrical channel

Using a method which averages the system of moment equations over the channel section, the authors have obtained expressions for Poiseuille flow and thermal creep flow in a capillary at intermediate Knudsen numbers (Kn?0.25).     

Transient flow of rarefied gas through a short tube

A transient rarefied gas flow through a short tube is studied on the basis of the direct simulation Monte Carlo method. The mass flow rates through both inlet and outlet cross sections are calculated as a function of the time in the free-molecular, transitional and hydrodynamic regimes with respect to the gas rarefaction. Two values of the pressure ratio, i.e. 0.1 and 0.5, and two values of the aspect ratio, i.e. 1 and 5, are considered. A characteristic time equal to that needed to cross the tube radius with the most probable molecular speed is defined. A typical interval of time to establish the steady flow rates was calculated. It was found that this time is about ten and forty characteristic times for the shorter and longer tubes, respectively. The flow field for the longer tube is analyzed in details.     

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.     

Mass transfer in a solid particle with competing reactions with a multicomponent gas mixture

A macrokinetic model of the transformation of a solid particle, reacting with a multicomponent gas mixture, is constructed for arbitrary ratios between the rates of the mass-transfer stages of the transformation process (sorption, dissolution, and diffusion of the starting and final products).Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 51, No. 1, pp. 84–92, July, 1986.     

Theoretical investigation of nonisothermal flow of a rarefied gas in a cylindrical capillary

This paper calculates thermocreep and Poiseuille flow in a cylindrical capillary using the Bubnov-Galerkin method. Asymptotic formulas are obtained for flow in the viscous regime with slip.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 36, No. 1, pp. 86–93, January, 1979.     

A method of studying the state of a rarefied gas

We propose a mathematically correct method of solving the Boltzmann equations.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 16, No. 5, pp. 885–891, May, 1969.     

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.     

Filtration of rarefied gas through porous bodies

The filtration of a rarefied gas through porous bodies of various structures, porosities, and geometries was studied under various flow modes with the Knudsen number ranging from 10^–4to 2.5.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 23, No. 5, pp. 820–828, November, 1972.     

Pressure driven rarefied gas flow through a slit and an orifice

The flow of a monatomic gas through a slit and an orifice due to an arbitrarily large pressure difference is examined on the basis of the nonlinear Bhatnagar-Gross-Krook (BGK) model equation, subject to Maxwell diffuse boundary conditions. The governing kinetic equation is discretized by a second-order control volume scheme in the physical space and the discrete velocity method in the molecular velocity space. The nonlinear fully deterministic algorithm is optimized to reduce the computational effort by introducing memory usage optimization, grid refinement and parallelization in the molecular velocity space. Results for the flow rates and the macroscopic distributions of the flow field are presented in a wide range of the Knudsen number for several pressure ratios. The effect of the various geometric and physical parameters on the flow field is examined. Comparison with previously reported corresponding Direct Simulation Monte Carlo (DSMC) results indicates a very good agreement, which clearly demonstrates the accuracy of the kinetic algorithm and furthermore the reliability of the BGK model for simulating pressure driven flows.