Natural convection over rotating cylindrical heat source in an enclosure

Mixed convection heat transfer induced by the mutual interaction between natural convection and a rotating cylindrical heat source in rectangular enclosures is investigated for different geometric settings of the heat source. The governing conservation equations of mass momentum and energy are solved numerically using the spectral element method. The numerical results are validated against experimental heat transfer correlations available on the natural convection of stationary heated bodies in enclosures. Heat transfer rates due to the heated cylinder rotation are found to depend on the location of the cylinder with respect to the enclosure bottom wall and on the enclosure size. When only natural convection is present, a decrease in the mean Nusselt number is observed as the cylinder is moved upward and as the enclosure AR is reduced. Rotation of the heat source decreases the mean Nusselt number of the cylinder by 10-20% at low RalRe^ as compared to the pure natural convection case when the source is stationary. Enhancement of heat transfer is present only for values of RalRe^ greater than 10. In all geometric configurations the maximum temperature on the cylinder surface is reduced by 10— 25%, depending on the rotational speed and position of the heat source, and the Rayleigh number of the flow and the angular position of the maximum temperature is shifted from the top of the cylinder for the case of pure free convection to a new position in the direction of rotation. C d