Experimental Study of Natural Convection from Arrays of Square Fins with Various Fin Spacing

In the present study, natural convection heat transfer of three finned-tube exchangers with array of square fins is analyzed experimentally. Total length of each exchanger is 200 mm and the length of the covered zone with fins is 100±1 mm. The fin spacing (s) is changed from 5 to 14 mm. For study of natural convection heat transfer, various fin spacing and thermal input power (Q) are examined. For experiments, the exchangers are placed in a control room in which its temperature and humidity are automatically controlled via heating, cooling, humidifying equipment. The thermal input power for heating varied from 8.4 to 56.7 Watt. Based on experimental results, an empirical correlation is developed for Nusselt number when Rayleigh number based on the fin spacing is changed from 6.5 to 1335.