Parametric Study on Natural Convection From Novel Vertical Heatsinks With Partially-Open Ducts

Abstract This study conducts a numerical parametric study for natural convection from isothermal partially-open duct heatsinks (PODHSs). The novel PODHS exhibits significantly improved thermal performance over traditional plate-fin heatsinks (PFHSs) and closed-duct heatsinks (CDHSs). The superiority is mainly because pairs of swirly rising airflow are induced by the mirror-symmetric partial openings to mix with the outside cold air. Using ANSYS Fluent@, which has been carefully validated by our previous work for heatsink height H = 200 mm, computations are conducted for PODHSs, CDHSs, and PFHSs. The experimental validation of the numerical computation is also conducted for the three types of heatsink at H = 200 mm. The flow characteristics and thermal performances are revealed for H = 100–700 mm and Lf = 16–50 mm. The opening widths, all around 2 mm, are, respectively, determined for different fin geometries. The computation results for various values of H and Lf indicate the superiority of the convective heat transfer of the present PODHSs over the other CDHSs by 5.8–14.4% and PFHSs by 11.4–37.6% at their respective optimum fin spacings. Under laminar flow condition, a PODHS with H = 700 mm can use 50 mm long fins to raise the heat dissipation ability to 1271.4 W/m at an optimum fin spacing of 16 mm. The results are useful in the optimal design for vertical heatsinks applied for outdoor or indoor facilities, such as 5G base stations and fanless computers.