Performance evaluation of a porous-fin heat sink for electronic device thermal management: an experimental study

• A novel porous-fin heat sink with high heat transfer performance. • Experimental comparison of porous- and solid-fin heat sinks under free and forced convection. • Porous fins increases heat transfer by up to 15.8% (free) and 36.9% (forced). • Enhancement arises from flow penetration, mixing, and reduced thermal resistance. • Heat-transfer improvement decreases with higher heat flux and Reynolds number. In this study, the thermal performance of a porous-fin heat sink under free and forced convection conditions is experimentally investigated and it is compared with a solid-fin heat sink to evaluate the improvement in cooling effectiveness. The porous-fin heat sink geometry is produced in a multi-step molten casting process using rock salt. The aluminum porous fin exhibits 73% porosity with interconnected 3.5–4 mm pores, combining high surface area and permeability. For comparative testing, a solid-fin heat sink with the same size is also fabricated. Experiments are carried out at different imposed heat fluxes and air flow rates to measure the local and average heat transfer coefficients. It is observed that the use of porous structure results in a significant increase in heat transfer compared to the solid heat sink, such that in free convection the heat transfer rate increases by up to 15.84%, while in forced convection a maximum increase of 36.85% is achieved at Reynolds number of 1450. This improvement is attributed to the increase in effective contact area, flow penetration into porous material, local mixing and reduction of thermal resistance in porous structure. The results show that the relative enhancement of heat transfer decreases as the applied heating power or Reynolds number increases, indicating an inverse relationship between these parameters and the observed improvement. Moreover, variation of the local heat transfer coefficient along the flow direction on the heat sinks shows that the porous heat sink leads to more uniform temperature distribution. The obtained experimental data are used to develop correlations for predicting the thermal performance of the heat sinks.