M.R. Sohel

Nanofluids for Thermal Performance Improvement in Cooling of Electronic Device

Nanofluid is a promising coolant for high-heat dissipation electronics device or system. The effect of nanofluids as thermal performances on a rectangular shape microchannel heat sink (MCHS) is analytically studied. Al2O3, SiC, and CuO nanoparticles dispersing in water were considered for analysis. A steady, laminar, and incompressible flow with constant heat flux was assumed in the channel. Nanofluids with concentrations of 0.5 to 4.0 vol. % were analyzed at two different inlet velocities of 0.5 m/s and 3.0 m/s. The results showed that highest thermal conductivity enhancement was 12.45% by using SiC-water nanofluids. In the case of Al2O3-water and CuO-water nanofluids maximum improvement were 11.98% and 11.36%, respectively for 4.0 vol. % of nanoparticle concentration. Furthermore, nanofluids as a coolant instead of water showed a highest improve of heat flux 8.51% for water-CuO, and 6.44% and 5.60% increase for Al2O3-water and SiC-water, respectively. The maximum pumping power found 0.33 W at 3 m/s and 0.0091 W at 0.5 m/s for the same concentration of 4.0 vol. % for all of these nanofluids.

Performance Investigation of a Plate Heat Exchanger Using Nanofluid with Different Chevron Angle

Plate heat exchanger with chevron angle has higher heat transfer area than flat type and increases the level of turbulent due to its corrugated channel. In this study, both water and nanofluid were used to determine the heat transfer coefficient and rate, pumping power, and pressure drop. A commercial plate heat exchanger with two different symmetric (300/300, 600/600) and one mixed (300/600) chevron angle plates were considered for analysis. Al2O3 and SiO2 nanoparticles with 0-1 vol. % concentration were used with water. From the analysis it was found that, convective heat transfer coefficient, heat transfer rate, pressure drop and pumping power increases with the increase of volume concentration. Moreover, the above parameters were found to be higher for 600/600 chevron angle plates. A correlation of Nusselt number as a function of Reynolds number and Prandtl number for different chevron angles needs to be obtained based on experimental and analytical work. Nomenclature

Investigation of Heat Transfer Performances of Nanofluids Flow through a Circular Minichannel Heat Sink for Cooling of Electronics

Nanofluid is the suspension of nanoparticle in a base fluid. In this paper, the heat transfer performances of the nanofluids flow through a circular shaped copper minichannel heat sink are discussed analytically. Al2O3-water, CuO-water, Cu-water and Ag-water nanofluids were used in this analysis to make comparative study of their thermal performances. The hydraulic diameter of the minichannel is 500 μm and total block dimension is 50mm× 50mm× 4mm. The analysis is done at different volume fractions of the nanoparticle ranging from 0.5 vol.% to 4 vol.%. The results showed that the heat transfer performance increases significantly by the increasing of volume fraction of nanoparticle. Ag-water nanofluid shows the highest performance compared to the other nanofluids. So, this nanofluid can be recommended as a coolant flow through a circular minichannel for cooling of electronic heat sink.