ENHANCED CONDUCTION IN STEADY, VERTICAL FLOWS OF WATER, STEAM AND CARBON-DIOXIDE IN A POROUS-MEDIUM

The steady, vertical transport of water, energy and carbon dioxide in a two-phase porous medium is analysed when capillarity can be ignored. Such flows are possible only if a compatibility condition on saturati on holds. Conditions are derived which allow three values of saturatio n for a given flux of mass, energy and carbon dioxide. The typical cas e has a significant fraction of the energy flux transported conductive ly. The corresponding high temperature gradients restrict such states to narrow vertical zones in which the rapid variation of temperature i s coupled to rapid changes in the partial pressure of carbon dioxide. This conductive mode of transport, together with convective transport in the vapour and liquid phases, provide three different methods for v ertical energy transport.