Numerical simulation of turbulent natural convection in an enclosure with a curved surface heated from below. (August 2020)

• Record Type: Journal Article
• Authors: Chai, Xiang; Li, Wei; Chen, Bin; Liu, Xiaojing; Xiong, Jinbiao; Cheng, Xu
• Is Part Of: Progress in nuclear energy. Volume 126(2020)
• Publication Date: 2020-08
• Subjects: Turbulent natural convection -- Curved surface -- Launder-Sharma k-ε model -- Discrete heater; Nuclear energy -- Periodicals; Nuclear engineering -- Periodicals; 333.7924
• DOI: 10.1016/j.pnucene.2020.103392
• Languages: English
• ISSNs: 0149-1970

Abstract

Abstract: Natural circulation, which is employed in the design of a small modular reactor, influences the removal of decay heat from the upper header of a pressure vessel under severe accident conditions. This phenomenon has been emphasized for a better understanding of passive safety systems. In this paper, a Reynolds-averaged turbulence model is used to simulate turbulent natural convection in a rectangular enclosure with a curved surface heated from below. The simulation results are first compared with the Direct Numerical Simulation (DNS) of a differential heated cavity obtained from the literature. A good agreement demonstrated the ability of the employed computational fluid dynamics (CFD) approach to predict turbulent natural convection flow and its induced heat transfer. Consequently, the turbulent natural convection formed in a rectangular enclosure heated by a curved surface was investigated. The ensemble average was employed to evaluate the local Nusselt number distribution quantitatively as well as the velocity and temperature distributions. Their dependency was also evaluated based on a systematic CFD simulation that covers a wide range of Rayleigh numbers. Least square regression analysis was employed to propose a correlation to predict the averaged Nusselt number as a function of the Rayleigh number. The influence of the thermal boundary conditions and the discrete heater was also determined.