Abstract
In this paper, mixed convection in a horizontal channel partially filled with a porous medium and the lower wall heated at uniform heat flux is studied experimentally and numerically. A simplified two-dimensional problem is modelled and solved numerically. The domain is made of a principal channel and two channels with adiabatic walls, one upstream and the other one downstream the principal channel. The heated wall temperature profiles as a function of the Ri values are presented. Average Nusselt numbers are evaluated. The experimental test section is made up of a horizontal wall and a parallel adiabatic wall. The distance between the horizontal walls is equal to 40 mm. The porous medium is an aluminium foam and it is placed over the heated lower wall. The porous plate has a thickness equal to 20 mm. The aluminium foam has 10, 20 and 40 PPI. The experiments are performed with working fluid air. The Reynolds numbers investigated are between 5.0 and 250, these being in the laminar regime. The Richardson number, Ri, holds values in the range 1 2000. Results in terms of wall temperature profiles, local and average Nusselt numbers are presented for different Reynolds and Rayleigh number values. Some comparison between experimental and numerical results are accomplished.
Highlights
Mixed convection has a great importance in practical applications in various modern systems, such as electronic cooling, chemical vapor deposition, fire research, solar and geothermal energy plants and flat plate heat exchangers, as indicated in [1,2]
In this paper, mixed convection in a horizontal channel partially filled with a porous medium and the lower wall heated at uniform heat flux is studied experimentally and numerically
In this work, mixed convection in a horizontal channel partially filled with a porous medium and the lower wall heated at uniform heat flux is studied experimentally and numerically
Summary
Mixed convection has a great importance in practical applications in various modern systems, such as electronic cooling, chemical vapor deposition, fire research, solar and geothermal energy plants and flat plate heat exchangers, as indicated in [1,2]. They study the heat transfer characteristics of the mixed convection flow through a horizontal rectangular channel with three different pore densities (10, 20 and 30 PPI) They apply three values of a uniform heat flux, and temperatures are measured on the entire surfaces of the walls. Buonomo et al [20,21] numerically and experimentally study mixed convection in a horizontal channel filled with metal foam partially heated at uniform heat flux They consider an aluminum foam with 10 PPI and ε=0.909, the fluid is air. In this work, mixed convection in a horizontal channel partially filled with a porous medium and the lower wall heated at uniform heat flux is studied experimentally and numerically. Flow visualization is performed to detect the flow patterns into the cavity
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