Condensation on and evaporation from droplets by a moment method

Abstract

The moment method proposed by Lees (1959) is applied to the problem of vapour condensation on and evaporation from spherical liquid droplets when the droplet is not in equilibrium with its surrounding. Using a four-moment solution, an analytical expression is derived for the mass flux to or from the droplet surface when the droplet is surrounded by a pure vapour. By neglecting changes in temperature, an analytical solution is also obtained for the mass flux when the droplet is immersed in a vapour-gas mixture. The results of both of these analyses are applicable in the range from λ/R → 0 to λ/R ∞, where λ is the mean free path and R the droplet radius, and it is shown that in the limits the results reduce to the appropriate free molecule and continuum expressions.

Asymptotic solution and numerical simulation of homogeneous condensation in expansion cloud chambers

“…Young's results agree well especially with the numerical simulations of the Boltzmann equation 28 and with the results of model kinetic equations. 29,30 In addition the transition from the kinetic to diffusion controlled limit is satisfactorily recovered in Young's formula. 27 However, Young's formula, as well as Gyarmathy's law given by Eqs.…”

Piecewise continuous distribution function method in the theory of wave disturbances of inhomogeneous gas

“…Solving a problem of of a shock wave structure [20,22,23] the solution was represented as a combination of two locally equilibrium functions, one of which determines the solution before front of a wave, and another -after. In the problem of condensation/evaporation of drops of a given size [24,25] a surface break was determined by so-called "cone of influence", thus all particles were divided into two types: flying "from a drop" and flying "not from a drop".…”

Piecewise continuous distribution function method: Fluid equations and wave disturbances at stratified gas

“…In a problem of a shock wave structures [27,28,29] the solution was represented as a combination of two locally equilibrium functions, one of which determines the function before front of a wave, and another -the tail. In a problem of condensation and evaporation of drops of any size [30,31] a break surface was determined by so-called "cone of influence", thus all particles were divided to two types: flying "from a drop" and flying "not from a drop".…”