A direct simulation code has been developed to solve two-phase flow with ma
ss transfer at the interface. The position of the interface is determined b
y solving a transport equation of the maker density function, one of front-
capturing methods. The present method performs the dissolution of mass of a
dispersed phase into a continuous phase as a notable feature. Moreover, tr
ansfer of the dissolved mass is solved in the continuous phase. At the inte
rface, mass diffusion flux is calculated both for the boundary condition of
mass transfer and for the shrinkage of a droplet. For the validation of th
e present method, three case studies are successfully demonstrated: rise of
single droplet, dissolution from a rigid sphere, and dissolution from a ri
sing droplet. [S0098-2202(00)01303-1].