Natural Convection Heat Transfer From Perforated Hollow Cylinder With Inline and Staggered Holes

Abstract

The continuity, momentum, and the energy conservation equation for air around a hollow cylinder with inline or staggered holes have been solved in three dimensions to assess the buoyancy driven flow and temperature field around the cylinder. From the thermal field, the average surface Nu could be computed for hollow cylinders with inline or staggered holes and the heat loss from the cylinder could be compared with that of a hollow cylinder without holes. Interesting flow and thermal plume around the hollow cylinder with holes could be seen, which could help to explain why there is more heat loss from a cylinder with staggered holes compared to a cylinder with inline holes at lower Ra of 105, whereas for higher Ra of 106 or more, there exists an optimum d/D where the heat loss from the perforated cylinder has a maximum value and thereafter it reduces. There are interesting comparisons on Nu for the hollow cylinder with inline or staggered holes and new correlations for Nu versus many different pertinent input parameters have been developed for many cases, which can be used practically in industry for designing perforated cylinder with heat loss.