High mass flux mass transfer through a mobile interface.

A theoretical study was made of mass transfer in a laminar boundary layer through a mobile interface with high mass flux condition. The laminar boundary momentum and diffusion equations are solved numerically with Blasius-type similar transformations. The numerical results are obtained for mass transfer rates by taking account of the diffusional flow due to rapid mass transfer and interfacial velocity due to motion of interface simultaneously. Mass transfer rates are given as function of transfer number B (a dimensionless driving force of mass transfer to be related to diffusional flow), interfacial velocity parameter us/U∞ and Schmidt number. The results show that the interfacial velocity increases the mass transfer rates in the case of high mass flux as well as for low mass flux. This effect is very important in the high-Schmidt number region. The previous theories of high mass flux phenomena with fixed interface can be applied to high mass flux mass transfer with mobile interface as long as the effect of the interfacial velocity, in increasing the mass transfer rates, is considered.