Parametric study of natural convection heat transfer from an inclined rectangular cylinder embedded in a square enclosure

This paper presents the effects of aspect ratio (0.1 <= AR <= 0.7), Rayleigh number (10(2) <= Ra <= 10(6)) and inclination angle (0 degrees <= gamma <= 90 degrees) of the heated rectangular cylinder on heat transfer and fluid flow characteristics due to natural convection in air around heated rectangular cylinders of different sizes inside a cold square enclosure. Galerkin finite element method was adopted for the solution of the developed model. The walls of the enclosure were maintained at an isothermal cold temperature while the boundaries of the rectangular cylinder were kept at a constant hot temperature. The results are presented in the form of isothermal contours, stream functions, local and average Nusselt numbers. It has been found that for the range of aspect ratio and Rayleigh number considered, the rate of heat transfer increases with increasing aspect ratio and Rayleigh number. Furthermore, the orientation angle of the rectangular cylinder was found to generally augment heat transfer rate except at AR value of 0:1, where the average Nusselt number declines beyond gamma = 45 degrees for all the range of Rayleigh numbers considered. Results from the present study could be applied to nuclear reactor technology and cooling of electronic chips system optimisation.