An experimental and numerical analysis of natural convection in a partially open cuboid enclosure with a cylindrical obstacle

Abstract

Natural convection in partially open enclosures has been area of intensive research in the past. However, a dearth of experimental or numerical studies has been found on the effect of cylindrical obstacle size on natural convection in such an enclosure. To address this gap, this study employs real-time experimental analysis using a non-invasive technique (Mach-Zehnder interferometry), that provides temperature distribution of flowing fluid in the investigating domain. The experiments are conducted in a partially open cuboid enclosure with an internal heat source on the bottom wall and a centrally placed cylindrical obstacle. The partial opening occupies 50% of the height of the left vertical wall. The study investigates the effect of obstacle diameter and Rayleigh number on natural convection through experimentation and numerical simulations using ANSYS Fluent 2020. An air velocity transducer is used to measure velocity at the opening. The interferograms obtained from the experiment are used to characterize the natural convection and compared with the results obtained from the numerical investigation. Fringes intensify at higher Rayleigh number, and the temperature gradient near the heat source increases with increase in obstacle diameter. The average Nusselt number and average exit velocity of flowing fluid increase with increase in obstacle diameter and Rayleigh number. For Rayleigh numbers in the range of 107 to 108, a threefold increase in the obstacle diameter results in an average increment in Nusselt number by 22% and an increment in the average exit velocity by 25%. � 2023 Elsevier Ltd