Fast development of electronic components and as a result, increase of the heat flux generated by them, creates a need for an effective approach for cooling the electronic units. The previous cooling approaches do not respond to this increasing need of heat removal. Researchers are investigating new efficient ways to remove more heat from electronic components. Microchannels heat sinks have received lots of attention due to their high heat transfer rate and the fact that they need a small amount of cooling liquid. The aim of this work is to geometrically optimize the rectangular microchannel with a Y shaped fin in the center of the microchannel to decrease its maximum temperature. To this end, a 3D simulation of forced laminar flow in a microchannel equipped with a Y shaped fin at its center has been performed. Water has been considered as the coolant. Seven degrees of freedom have been considered in optimization process. Moreover, the optimization has been done under two constrains, namely constant microchannel overall volume, and microchannel solid volume. The pressure difference over the microchannel has been set fixed as well. The microchannel substrate receives uniform heat flux along the channel. In this project the constructal theory has been invoked to reach the optimization. Initially, an introduction to microchannels and constructal theory is presented, then the seven degrees of freedom have been defined, optimized and then the results have been discussed. The results show that after optimization, the maximum temperature of the microchannel heat sink has been decreased up to 6.5 degree Celsius, compared to the initial microchannel. Lastly, a porous medium has been used as the constituting material of the Y shaped fin in the optimized microchannel heat sink; where the results showed that the microchannel heat sink with porous fin has an inferior performance comparing to the microchannel heat sink invoking a non-porous Y-shaped fin. Keywords Constructal theory, Microchannel heat sink, Double layer, Y-shaped fin, Optimization, Porous media.
