Numerical Investigation of Turbulent Convection Flow in a Rectangular Closed Cavity

Abstract

Natural turbulent convection in closed cavities has many practical applications in the field of engineering
such as the design of electronic computer chips, atomic installation and industrial cooling among others. In
particular, it enables in achieving a desired micro-climate and efficient ventilation in a building. Recent studies
show that turbulent flow is affected by variations in Rayleigh numbers, aspect ratio, and heater position
among others. Temperature is kept constant in all these studies hence inadequate literature on the effects
of temperature on a turbulent flow. In this study, aspect ratio and Rayleigh numbers are kept constant at
2 and 1012 respectively and natural turbulent convection flow in a closed rectangular cavity is investigated
numerically as the operating temperature is varied from 285.5K to 293K. The rectangular cavity’s lower wall
was heated and cooling done at the top face wall while the rest of the vertical walls were kept in adiabatic
condition. Material properties such as density of the fluid kept on changing at any given temperature. The
thermal profile data generated influenced the nature of the turbulent flow. The non-linear averaged continuity,
momentum, and energy equation terms were modeled by the SST k − ω model to generate streamlines,
isotherms, and velocity magnitude for a different operating temperature and presented graphically. The finite
difference method and FLUENT were used to solve two SST k − ω model equations, vortices, and energy with
boundary conditions. It was discovered that, as the operating temperature increased turbulence decreased
due to a decrease in the velocity of the elements and vortices became more parallel and smaller.