Improvement of hydrothermal performance of microchannel heat sinks using V-shape pin-fins and Al2O3 / water nanofluid

Increasing heat transfer with decreasing pressure drop and reducing size of heat transfer system is of subjects studied over four decades. Generally, microchannels can stabilize the laminar flow in channels so that high heat transfer coefficients can be obtained. In this research, two general geometries (Straight and V-shaped) with four different types of interruption (Integral, Integral-Interrupted, Interrupted-Inline, Interrupted-Staggered) are studied. Water as working fluid is considered. The effects of geometries and pin-fins interruption on performance enhancement of microchannel heat sinks were investigated at various Reynolds number (100-900). Important parameters such as base temperature, Nusselt number, pressure drop, heat transfer coefficient and hydrothermal performance factor were evaluated. The simulations have been carried out using Fluent 17 software. The results show that interrupted microchannels improve the heat transfer coefficient and Nusselt number compared to integral microchannels. They also generate a more uniform temperature distribution without hot spots in the microchannel. Microchannels with a V-shaped pin report better results due to turbulence in the bulk flow and the generation of vortex. Through different configurations, the Interrupted-Staggered configuration for both straight and V-shaped geometries shows the highest hydrothermal performance factor with increase of about 1.5 times in comparison to the Straight-Integral model. Then, by changing the working fluid with water/Al2O3 nanofluid, its effect was studied. Nanoparticles increased the hydrothermal performance factor approximately 1.83 times in the case of Straight, Interrupted-Staggered and about 1.77 times in the case of V-shaped, Interrupted-Staggered. Increasing the concentration of nanoparticles also improved the hydrothermal performance.