Evaporative heat transfer of water-containing porous plate exposed to a high temperature surface with a narrow gap

摘要

The heat transfer from a high-temperature solid surface to a porous plate containing water and separated by a narrow gap and the resulting evaporation rate of water from the porous plate are investigated experimentally. The heat transfer and evaporation rates increase with the solid surface temperature up to 1,273 K, while the temperature near the upper surface in the plate remains close to the saturation temperature. The resulting heat flux to the porous plate is much smaller than the maximum heat flux, which is estimated as the limit of the evaporation at the capillary meniscus in pores adjacent to the heated surface. The transferred heat is mainly consumed as the latent and sensible heats of the vapor. Even after the cessation of water supply from the lower surface, the upper surface temperature of the porous plate and the evaporation rate remain close to the values before cessation, until the critical moisture content of the material is reached.