关键词: 薄膜理论;气体;液体;转移模式;表面恢复理论;渗透理论;扩散

Abstract: A gas-liquid mass transfer model based on an unsteady state film mechanism applied to a
single bubble is presented. The mathematical model was solved using Laplace transform to
obtain an analytical solution of concentration profile in terms of the radial position r
and time t. The dynamic mass transfer flux was deduced and the influence of the bubble size
was also determined. A mathematical method for deducing the average mass transfer flux
directly from the Laplace transformed concentration is presented. Its accuracy is verified
by comparing the numerical results with those from the indirect method. The influences of
the model parameters, namely, the bubble size R, liquid film thickness δ, and the surface
renewal constant s on the average mass trannsfer flux were investigated. The proposed model
is useful for a better understanding of the mass transfer mechanism and an optimum design
of gas-liquid contact equipment.

Key words: film theory, Laplace transformation, mass diffusion, penetration theory, surface renewal theory