Interfacial transfer between a multiphase medium and its surroundings are generally described by transfer coefficients which can be theoretically determined only under boundary layer hypothesis. In the case of the vacuum drying, this kind of model is not valid. The approach proposed in this work consists in solving equations of conservation for each medium and linking the domains by fixing the appropriate boundary conditions. In order to solve the transfer problem, a coupling method between the numerical code devoted to the porous medium and the CFD one (FLUENT) is achieved. The pressure conditions are low enough so that boiling occurs in the porous medium. The results lead to a better understanding of the local physical phenomena, due to the coupled analysis of internal and external transports. (c) 2006 Elsevier B.V. All rights reserved.