FORCED CONVECTIVE HEAT-TRANSFER IN A VERTICAL ANNULUS FILLED WITH POROUS-MEDIA

Experiments on forced convective heat transfer were conducted for water or transformer-oil flowing upward through a vertical annulus filled with different size porous media. The thermal dispersion caused by successive flow disturbance due lo the existence of porous media may have significant influence on the Nu value in the thermally fully-developed region, and a new model is proposed to consider the thermal dispersion as related to the geometrical parameters of porous media and the flow characteristics. The temperature distribution near the wall surface, and hence the convective heat transfer coefficient, can be thus predicted, which agrees well with the experimental results.