Stability of operation of an apparatus containing a granular bed fluidized by a gas stream

The results of numerical experiments on the investigation of the stability of the fluidization process relative to finite perturbations and its behavior upon crossing the boundary of stability are presented.Notation H bed height - H₀, H_* bed heights in motionless and steady fluidized states - g free-fall acceleration - k₁, k₂ coefficients of resistance of gas-supply system and gas-distributing device, respectively - M molecular weight of gas - m mass of bed per unit cross-sectional area - p^*, p⁰ pressure at inlet and outlet of apparatus - Q₀, Q_b minimum fluidization velocity and average velocity of gas in the bubble phase - q, q_v total mass-flow rates of gas supplied to the bed and to the free cavity - R gas constant - S cross-sectional area of bed - V volume of cavity below gas-distributing grid accessible to the gas - gas density - T absolute temperature - c,, q₀ parameters introduced into (4) - t time - z dimensionless bed height - x dimensionless time - A, B, C, D, N, n dimensionless complexes introduced into (5) - v dimensionless volume - parameter introduced into (5) - z_* dimensionless bed height in steady fluidized state - circular frequency Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 33, No. 5, pp. 889–892, November, 1977.     

Theory and Calculation of the Condensation Growth of a Droplet in Pure Vapor and in a Vapor–Gas Mixture

Consideration is given to the theory of condensation as applied to the liquefaction of gases. Numerical calculations of the growth of a droplet using methane as an example revealed the decisive role of heat removal from its surface to the ambient medium in condensation from both a pure vapor and a vapor–gas mixture. It is shown that for very low supersaturations of the vapor, radiative heat removal can prevail over convective heat removal.     

Special features of compacting aluminum powders in cold pressing

Translated from Poroshkovaya Metallurgiya, No. 3(303), pp. 33–38, March, 1988.     

Modeling of Gas Cooling and Condensation in a Piston Expansion Machine

A model of gas cooling and condensation in a piston expansion machine has been developed with allowance made for formation of nuclei of the liquid phase and growth of droplets as well as for real thermophysical properties. Internal heat release related to phase transition is taken into account in the adiabatic equation. The processes of cooling and liquefaction of methane in the piston expander are calculated for specific conditions.     

Diffusion of metal vapors in gases and the transport properties of vapors

Test data on the diffusion of metal vapors in gases and on the viscosity of the vapors are generalized. The ionization energies and the polarizabilities are chosen as the scales.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 42, No. 6, pp. 930–937, June, 1982.