Résumé:
A numerical study of laminar mixed convection air-cooling of two identical heat sources enveloped by a porous matrix has been presented in this work. The flow field is governed by the Navier–Stokes equations in the fluid region, the Darcy–Brinkman–Forchheimer model in the porous region, and the thermal field by the energy equation. The numerical calculation was carried out using the software ""FLUENT"", based on the finite volume method.
The first application is to examine the effects of the Reynolds number, the inclination angle, the size of electronic components and the space between them on the heat transfer inside a two-dimensional (2D) vertical channel. The results show that increasing of the Reynolds number and the separation distance can enhance the cooling of electronic components. For an inclinaison angle (α = 45 °), the maximum heat transfer was obtained. For the second application, we have considered a two-dimensional (2D) vertical channel, containing two electronic components wrapped by a porous matrix. The effects of the Reynolds number, the inclination angle, the Darcy number, the thickness of the porous layer and their conductivity have been examined. The results show that the thickness of the porous matrix improves the cooling of electronic components inside the channel, about 60% higher compared to the case without integration of the porous matrix. The increase of the Darcy number (10-3 ≤ Da ≤ 10-6) causes a decrease of the maximum temperature in the channel, which contributes to the cooling of electronic components. The insertion of the porous matrix with a thermal conductivity in the range ke/kf ≤ 50 improves the cooling of heat sources. For the third application, we have considered a three-dimensional (3D) vertical channel, containing two electronic components wrapped by a porous matrix. The effects of the Reynolds number, the Darcy number and the thickness of the porous layer have been examined. The results show that proper cooling of electronic components is obtained for a channel completely filled with a porous matrix with high thermal conductivity (ke / kf = 100), with Re = 200 and Gr = 104 ( Ri = Gr/Re2=0.25) and for all values of the Darcy number (10-3 ≤ Da ≤ 10-6).
