Experimental study has been investigated to study the free convective heat transfer from a vertically rectangular fin array. It fabricated from Aluminum which is having six fins. Each Finhas thickness and fin spacing were 4 mm and 10 mm respectively. The fin length is 300 mm. Fin height was selected 10 mm, 25 mm and 45 mm respectively. A Rayleigh number ranging from 7.6 × 10 − 1.5 × 10 were used. Heat input was varied from 68 W to 716 W were supplied for all fin configurations. The base and the ambient temperatures were measured in order to evaluate the heat transfer rate from fin arrays. The effects of fin heights with different heat input on the performance of fin arrays were observed. The results show the convection heat transfer coefficient, convection heat transfer rate, Nusselt number (Nu) and the Rayleigh Number (Ra) from fin arrays depends on fin height and reach to maximize value with fin height 45 mm. Otherwise, it has a minimum value at 10 mm fin height, the opposite behavior of average temperature decreases. The enhancements in the convection heat transfer coefficient and the base to ambient temperature difference (decreases), were 44% and 41%due to increase fin height from 10 mm to 45 mm. An empirical correlation relating Nusselt number to the influencing parameters (Rayleigh number and fin height) has also been suggested with a maximum variation of ±10% and as follows.
