Numerical study of chip cooling with internal nanofluid in minichannels and external air flow over sink with laminar regimes

In this work, an electronic computer chip generates a 50- 150 W heat over a 40mm x 40mm surface, requiring dissipation of about 9.5 x 104W/ m2. The authors design a copper heat sink ( 40mm x 40mm x 5 mm) that is mounted over the chip with two active methods for enhancing heat removal from the chip. To enhance the cooling effects, a laminar developing heat and fluid flow is introduced into the assumed seven miniature channels in a rectangular shape ( 2mm x 4 mm), which takes away heat partly. Ethylene glycol as a base fluid and ethylene glycol + Al2O3 as a nanofluid with a volume fraction of nanoparticles 0.5, 1 and 1.5% flow with laminar regimes. To remove heat from the other parts of the sink, an external airflow is used with a free stream velocity of 2 m/ s over it. This airflow is a laminar twodimensional boundary layer over the sink in the direction of its length. By numerical simulation, these two methods of cooling are investigated for enhancing heat removal from the sink. The results show cooling efficiency increased by about 8.5% in comparison with the cooling system with free convection where there is an internal cooling.