Thermal Management of Heat Sinks Equipped with Internal Cooling Mechanism: A Comparison with Advanced Heat Dissipation Techniques

Thermal management devices aim to remove extra heat from heat generation devices. There are numerous ways of heat rejection from the source, including active and passive cooling. The cooling techniques may be natural or forced, and the popular tools are heat pipes, heat sinks, and heat exchangers. In this piece of literature, several heat pipe and heat sink configurations are tested, including a novel internally cooled configuration using mono and hybrid nanofluids. Among heat sinks, solid finned and hollow finned configurations are mainly compared with the state-of-the-art heat pipes and thermal management systems for broader comparisons. Solid cylindrical fins are considered the baseline model, elliptical as well as semi-circular wavy are derived units, and hollow cylindrical fins are novel fin structures with important modification of water entrapment (filling ratio 50 %). Entrapped water acts as a cooling agent through heat normalization and distribution. External coolants used are water, Ethylene Glycol-based MgO nanofluids, as well as SiO2 nanofluids, and water-based (Fe2O3 + TiO2) hybrid nanofluids. Sintered copper wicked heat pipes are also diagnosed for performance evaluation with certain modifications. Tested heat pipe configurations include sintered wicked heat pipe with finless and finned arrangements, TiO2 nanofluid, and (TiO2 + SiO2) hybrid nanofluid-filled heat pipes. Heat sinks proved best for higher heat loads, whereas heat pipes are an effective and sustainable option for low power range applications. Hollow cylindrical finned heat sinks possess the highest heat transfer performance factor (HTPF), followed by elliptical finned heat sinks. Based upon HTPF, hollow cylindrical finned heat sinks are preferred, whereas among heat pipes, nanofluid-filled heat pipes with fins are the best option. For water as a coolant and at 15 Watt heat input, compared to the cylindrical finned heat sinks, the elliptical, semicircular, wavy, and hollow cylindrical finned heat sinks present 20.6 %, 24.5 %, and 29.8 % higher Nusselt numbers. There is a requirement for flow rate optimization for sustainable and optimized thermal management systems.