Natural convection in asymmetric triangular enclosures heated from below

32nd UIT (Italian Union of Thermo–fluid-dynamics) Heat Transfer Conference

物理学;力学

Kamiyo, O.M.^1 ; Angeli, D.^2 ; Barozzi, G.S.^3 ; Collins, M.W.^4

Department of Mechanical Engineering, University of Lagos, Lagos, Nigeria^1

DISMI-Dipartimento di Scienze e Metodi dell'Ingegneria, Universita di Modena e Reggio Emilia, via Amendola 2, Reggio Emilia

I-42122, Italy^2

DIEF-Dipartimento di Ingegneria enzo Ferrari, Universita di Modena e Reggio Emilia, via Vignolese 905, Modena

I-41125, Italy^3

School of Engineering and Design, Brunel University, Uxbridge, Middlesex

UB8 3PH, United Kingdom^4

关键词: Attic spaces;    Base wall;    Laminar airflow;    Pitch angle;    Pitched roofs;    Rayleigh number;    Triangular enclosure;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/547/1/012043/pdf
DOI  :  10.1088/1742-6596/547/1/012043

学科分类：力学，机械学

来源: IOP

【 摘 要 】

Triangular enclosures are typical configurations of attic spaces found in residential as well as industrial pitched-roof buildings. Natural convection in triangular rooftops has received considerable attention over the years, mainly on right-angled and isosceles enclosures. In this paper, a finite volume CFD package is employed to study the laminar air flow and temperature distribution in asymmetric rooftop-shaped triangular enclosures when heated isothermally from the base wall, for aspect ratios (AR) 0.2 ≤ AR ≤ 1.0, and Rayleigh number (Ra) values 8 × 105≤ Ra ≤ 5 × 107. The effects of Rayleigh number and pitch angle on the flow structure and temperature distributions within the enclosure are analysed. Results indicate that, at low pitch angle, the heat transfer between the cold inclined and the hot base walls is very high, resulting in a multi-cellular flow structure. As the pitch angle increases, however, the number of cells reduces, and the total heat transfer rate progressively reduces, even if the Rayleigh number, being based on the enclosure height, rapidly increases. Physical reasons for the above effect are inspected.