Thermal Improvement in Double-Layered Microchannel Heat Sink with Incorporating Wavy Porous Fins

A new configuration of microchannel heat sink with a superior heat removal capability is proposed. The proposed geometry consists of double-layered wavy channels with porosity inserted on the top layer. A conjugate heat transfer numerical solver is employed to compare thermal and hydrodynamic properties of the proposed configuration with other possible double-layered wavy and rectangular geometries with/without porous fins. Even though the rectangular configurations represent lower pressure drop, their thermal performance is generally weaker than their wavy counterpart at the same pumping power. Lowest thermal resistance is achieved by utilizing the proposed design compared to other investigated geometries at the same imposed heat flux and pumping powers. The enhancement in overall thermal performance is attributed to the combined effects of secondary flow induced by the channel waviness and penetration of coolant flow in the top-layer porous fins. Moreover, the impacts of wavelength and amplitude on the thermal resistance of the proposed configuration are examined. It is shown that increasing the wavelength leads to a sharp decrease in thermal resistance at lower wavelengths, followed by a slight rise in higher longitudinal periods. Conversely, increment in amplitude causes a monotonous reduction in thermal resistance.