عنوان مقاله [English]
In the present study, two geometries of microtube and microchannel are used simultaneously in a heatsink. The aim is to improve the performance of micro heatsink in cooling digital processors. ANSYS FLUENT software is employed to solve the governing equations. The second-order upwind method is utilized to solve the momentum equation and the SIMPLE method is employed for coupling the velocity and pressure fields. The results show that the fluid flow temperature changes less along with the micro heatsink by increasing the Reynolds number due to the high flow rate. Also, the surface temperature of the processor decreases significantly by enhancing the concentration of nanoparticles and improving the heat transfer performance. Hence, at Re =700 and a volume fraction of 0.5%, the average outlet temperature of the system is 316.1 K. It is equal to 319.03 K for a volume fraction of 1%. The addition of microtubes also causes a significant increment in the overall thermal efficiency of the system. For example, at Re = 300, the heat transfer coefficient for the base fluid flow with microtubes is approximately 58.4% higher than that for the system without microtubes. At Re =700 and 1500, this enhancement is 63.3% and 50.9%, respectively. This indicates that the presence of microtubes improves the performance of the heatsink and the access of heat transfer in different parts of the equipment to the cooling fluid flow. It reduces the thermal resistance of far points of the processor, leading to more heat absorption from the CPU surface.