On the effects of Rayleigh number and inlet turbulence intensity upon the buoyancy-induced mass flow in sloping and convergent channels

Abstract

A numerical study on the mass flow rate induced by natural convection in a sloped converging channel for different inclination and convergence angles with summetrical heating has been reported. Two-dimensional, laminar, transitional and turbulent different general purpose codes: Fluent and Phoenics. In transitional and turbulent cases, the low-Reynolds k-w turbulence model has been employed. Special emphasis has been carried out, for turbulent regime, on the systematic comparisons of computational results with experimental and numerical data taken from literature, considering the influence of inlet turbulence intensity upon transitional point. Numerical results were obtained for wide and not yet covered ranges of the modified Rayleigh number varying from 10 high at (-2) to 10 high at (12), the aspect ratio between 0.03 to 0.25, the converging angle from 1º to 30º and sloping angle from 0º to 60º. A generalized crrelation for the non-dimensional mass flow rate has been obtained from numerical results in a channels with isothermal plates, for symmeric heating conditions.