Experimental research on natural heat transfer of air in vertical narrow rectangular channels

Experimental researches on natural heat transfer of air in three vertical narrow rectangular channels are conducted. These three channels are 800 mm in length, 60 mm in width and 1.0 mm, 1.8 mm and 2.5 mm in gap depth, respectively. By electrically heated with stainless heating rod, the natural heat transfer characteristics are investigated with or without an adiabatic chimney at the channel outlet. It is found that the impact of chimney on natural heat transfer characteristics is slight of channel with 1.0 mm and 1.8 mm gap depth, while that of channel with 2.5 mm gap depth depresses the heat transfer. Furthermore, the heat transfer data with or without chimney can be well correlated in two different correlations, respectively.