Transient multiphase flow of a multicomponent system with phase change in porous media

This paper presents a new model for the calculation of the transient multiphase flow of a multicomponent system in a porous media. Starting point is the development of a new process including the heat up of bulk goods using hot water and saturated steam. A precise model for the condensing flow of steam in porous media is necessary for further understanding. Existing models appear to be not appropriate because fundamental simplifications are made. As a consequence the physics of the process are not reproduced properly. The newly developed complex model eliminates all major simplifications. The system of the governing differential equations is reduced by the application of a mixture model for the fluid phases and a thermodynamic backwards calculation of the variables of state. Consistent and sufficiently exact equations of state and precise physical properties necessary for this calculation scheme are provided by the new steam table IAPWS97. An extended volume averaged momentum balance for each fluid phase is introduced. Concerning the heat transfer both the heat transfer between fluid and solid phase and the heat conduction in both phases are considered. The calculation scheme combines the simplifications of multiphase mixture models (MMM) concerning the reduction of the differential equation system and the accurate modelling of heat and mass transfer provided by separate flow models (SFM).