Influence of ceramic based nanofluids and inlet header geometry on the thermal performance of wavy microchannel heat sink

The increasing need for development in microelectronics and systems has naturally led to pursuit of modern advancements in the field of cooling technology. Microchannels offer excellent high temperature heat management in electronic systems. Microchannels utilize fluids capable of transferring heat energy released by the operating circuits by fluid flow. The fluid flow and nature of fluid are highly resonant on the performance of the microchannel heat sinks. The present work is a novel approach of an investigation of three-dimensional ceramic based nanofluids flow performance in a fabricated wavy microchannel heat sink with varying inlet header geometry. The coolant nanofluids investigated are concentrated with silicon dioxide (SiO2) and aluminum oxide (Al2O3) ceramic nanoparticles with varying volume percentages and their hydraulic and thermal performance were investigated. Experimental evaluations were performed to determine variations in local Nusselt number and axial coefficient of heat transfer for SiO2 and Al2O3 nanoparticles concentration. Computational fluid analysis was performed to evaluate transport equations to determine pressure drop, friction factor and Nusselt number of the fluid flow. It was observed that increasing heat flux amplitude causes rise of local maxima of Nusselt number with corresponding decrease of the local minima. The decrease of local minima was more profound than increase of local maxima. The different inlet header geometries influence the local Nusselt number with conical frustum header producing the value followed by semi-circular, rectangular and triangular inlet section geometries. The observed Nusselt number and heat transfer rate was highest in case of Al2O3 followed by SiO2 and distilled water as coolant fluids for the heat sink. Higher Nusselt number was observed for conical frustum and semi-circular inlet header geometries when SiO2 and Al2O3 based coolant fluids were used. High friction factor was observed when the nanoparticle concentration was 0.25 volume percentage for the entire Reynolds number under investigation. A computational model was utilized to evaluate the drops in pressure in the wavy microchannel and determine frictional characteristics of the nanofluids in the present work.

Automated summary

This study explored the flow performance of nanofluids with different inlet header geometries, finding that the heat transfer performance was optimal with coolant fluids based on aluminum oxide and silicon dioxide. The highest local Nusselt number and heat transfer rate were observed with high concentrations of SiO2 and Al2O3, indicating better performance with these coolant fluids.