Journal ArticleDOI
The spherical-droplet problem of evaporation and condensation in a vapour-gas mixture
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TLDR
In this paper, the behavior of a binary mixture of a vapour and an inert gas around the spherical condensed-phase droplet is studied analytically using kinetic theory, and the results obtained are capable of describing the transition from the diffusion-control to the kinetic-control mechanism in the mass transfer process.Abstract:
The behaviour of a binary mixture of a vapour and an inert gas around the spherical condensed-phase droplet is studied analytically using kinetic theory. By the singular-perturbation method, the linearized Boltzmann equation of B–G–K type is first solved for problems with spherical symmetry under the diffusive boundary condition when the Knudsen number of the problem is small. The macroscopic equations and the appropriate boundary conditions in the form of the temperature and partial-pressure jumps on the interface between the droplet and the gas phase, which enable us to treat the problems at the level of ordinary fluid dynamics, are derived together with the Knudsen-layer structure formed near the interface. Then the velocity, temperature and pressure fields around the droplet are explicitly obtained, as well as the mass, heat and energy flows from it. The results obtained are capable of describing the transition from the diffusion-control to the kinetic-control mechanism in the mass-transfer process. The negative-temperature-gradient phenomenon, a common phenomenon for pure-vapour cases (absence of inert gas), is also possible, manifesting itself more easily as the kinetic-control mechanism becomes prevalent and the critical condition for its existence is given. The present analysis could be applied to other problems with spherical symmetry as well.read more
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Kinetic theory approach to interphase processes
T. Ytrehus,S. Østmo +1 more
TL;DR: In this paper, the fluid and thermodynamics aspects of a vapor next to its interphase surface are studied under conditions of arbitrarily strong interphase processes in single component systems, where the physical domain considered is a boundary layer known as the Knudsen layer, a few molecular mean free paths thick, in which the vapor adapts to given external equilibrium conditions.
Journal ArticleDOI
The condensation and evaporation of liquid droplets at arbitrary Knudsen number in the presence of an inert gas
TL;DR: In this paper, a new set of equations describing the growth and evaporation of stationary liquid droplets in a mixture of pure vapour and inert gas is presented in a simple algebraic form and is suitable for practical calculations of droplet growth at any Knudsen number and at any concentration of inert gas.
Journal ArticleDOI
Kinetic theory in aerothermodynamics
TL;DR: In this paper, a review of the problems of a continuum flow regime which cannot be solved without regarding the gas as a collection of molecules is presented, and some of these problems are important for aerothermodynamics.
Journal ArticleDOI
Kinetics of Evaporation: Statistical Rate Theory Approach
Payam Rahimi,C. A. Ward +1 more
TL;DR: In this paper, the authors compared three theoretical approaches to study evaporation: Continuum Mechanics, Classical Kinetic Theory, and Statistical Rate Theory (SRT) and found that SRT can predict the conditions existing at the interface during evapse better than other methods.
Journal ArticleDOI
Laboratory Measurement of the Heat Capacity of Urania up to 8000 K: I. Experiment
TL;DR: In this paper, the authors measured the heat capacity of UO[sub 2] in a laboratory experiment where sintered 0.5-to 1-mm-diam microspheres were heated by four tetrahedrally oriented laser beams in an inert-gas-filled autoclave at pressures up to [approximately]1000 bar.
References
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Journal ArticleDOI
Kinetic Model for Binary Gas Mixtures
TL;DR: In this article, a method was developed for treating the Boltzmann equation for a binary gas mixture with inverse fifth power molecular interaction, where the complete collision integral was replaced with a kinetic model to reproduce the collisional transfer of momentum and energy for Maxwell molecules.
Journal ArticleDOI
Application of Kinetic Theory to the Problem of Evaporation and Condensation
TL;DR: In this paper, the motion of a vapor gas in contact with interphase surfaces is studied on the basis of kinetic theory of gases, and the mass and energy fluxes are determined from the condition of the vapor far away from the interfaces.
Journal ArticleDOI
Kinetic Theory of Evaporation and Condensation : Hydrodynamic Equation and Slip Boundary Condition
Yoshio Sone,Yoshimoto Onishi +1 more
TL;DR: In this article, the steady behavior of a gas in contact with its condensed phase of arbitrary shape is investigated on the basis of kinetic theory, and two simple examples (evaporation from a sphere, two-surface problem of evaporation and condensation) are worked out.