A numerical analysis and a 2D-PIV experimental study on the natural convection in a square cavity heated from below through an hot strip of different lengths and different positions

摘要

The aim of this paper is to determinate the influence of the position of a small heating source located in the bottom of a square cavity filled with air (Pr=0.71) on the natural convection flow structures and quantities (i.e. the distribution of the velocity vectors, the streamfunctions and the velocity fields). The experimental analysis was conducted through a 2D-PIV system. Two different positions are analyzed for the two dimensions of the strip: one for a dimensionless length of ε=1/5 and another for ε=2/5. For ε=0,2 we analyzed two dimensionless distances from the left side of the cavity δ=0,4 and δ=0,5; in the case of the dimensionless length of ε=0,4 we studied the symmetrical configuration (δ=0,5) and the dimensionless distance of δ=0,3. The effects of the positions of these hot strips are analyzed at different Rayleigh numbers: from 5·10{sup}4 to 6·10{sup}5. Then the results of the experimental PIV analysis were compared with the numerical results obtained with a finite volume code, Fluent 6.2.16, for both the geometrical positions of the heated strip.