Turbulent natural convection inside inclined enclosures: Effects of adiabatic and heat-conducting inserts

Abstract

Natural convection phenomena are found in many engineering applications, ranging from building and refrigeration design to nuclear reactors. Such importance has prompted both experimental and numerical studies aiming at enhancing heat transfer characteristics. Turbulent natural convection in closed cavities, apparently simple, is a stepstone to such problems, which require mathematical and numerical tools capable of providing accurate results. This work is inserted within this framework, in which influences of insert size and type (adiabatic/heat-conducting), and cavity inclination angle are assessed for Rayleigh numbers 10 7 ≤ Ra ≤ 10 9 . The study shows that the insert is mostly detrimental to heat transfer owing to restriction to recirculation, irrespective of the cavity inclination angle. An operation envelope for the global Nusselt number for all cavity inclination angles, insert sizes and types, and Rayleigh numbers was also determined.