Application of CNTs/H2O nanofluid and the wavy fin with dimples in thermal management of CPU: A numerical modeling of hybrid passive cooling

Abstract

A study was conducted utilizing computational fluid dynamics (CFD) to explore a novel cooling technique for the central processing unit (CPU), involving the use of carbon nanotubes (CNTs)/H2O nanofluid-fin heat sinks with dimples. Different fin heat sink designs with varying dimple arrangements were created using AutoCAD software. The three-dimensional flow, heat transfer, and mass transfer of the nanofluid within the liquid block were simulated using a finite volume-based CFD code. The study investigated the influence of different nanoparticle concentrations and dimple arrangements on cooling performance, heat transfer coefficient, pumping power, and thermal efficiency. The results revealed that the maximum temperature reduction on the CPU's top surface was approximately 13.1 K for multi-walled carbon nanotube/H2O nanofluids and 14.34 K for single-walled carbon nanotube (SWCNT)/H2O nanofluids. The best thermal efficiencies were achieved using SWCNT (2%)/H2O with three rows of dimples on each fin, resulting in an 8.5% improvement in heat sink performance at Re = 1,500 and an 8.8% improvement at Re = 2,000 compared to fins without dimples. However, it was observed that increasing the number of dimples on the fins led to an increase in pressure drop within the liquid block, necessitating additional pumping power. The simulation results aligned well with earlier experimental data and numerical studies in terms of cooling and heat transfer.