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

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