HEAT AND MASS TRANSFER ON POROUS MEDIUM SURFACE WITH VAPOR-LIQUID PHASE CHANGE
In this paper, the porous medium plate was chosen to recover moisture in the fuel cell exhaust and directly humidify the supply gas. From the view of heat and moisture transfer in self-humidification system, an experiment platform for convective heat transfer on porous media surface was constructed. The heat and mass transfer characteristics on the porous media surface accompanied by local phase change (condensation and evaporation) were researched systematically. The characteristics of latent heat transfer and sensible heat transfer, together with their dependence on gas parameters were analyzed. The results show that with the increase of temperature at high temperature and humidity gas side, the sensible heat transfer coefficient and latent heat (condensation) transfer coefficient at high temperature side increases obviously, while the sensible heat transfer coefficient and latent heat (evaporation) transfer coefficient at low temperature side had little change. Moreover, the mass transfer coefficient at side of high temperature is much higher than that of low temperature side. But, as the temperature at side of high temperature and humidity gas increases, the moisture transfer quantity increase, the mass transfer coefficient between high temperature side and low temperature side becomes smaller.