Optimization of thermal performances and pressure drop of rectangular microchannel heat sink using aqueous carbon nanotubes based nanofluid

• Optimization of 0.01% weight concentration of aqueous carbon nanotubes based nanofluid as coolant in a rectangular MCHS has been completed using the elitist non-dominated sorting genetic algorithm (NSGA-II) optimization procedure.
• The optimized thermal resistance for the nanofluid is better than that of water particularly at high temperature.
• The reduction in number of channels is very slight, a large quantity of 1 cm by 1 cm MCHS could mean savings in the production cost using nanofluid.

The present work focuses on analytical optimization of a rectangular microchannel heat sink using aqueous carbon nanotubes based nanofluid as coolant. The particles weight concentration used in this study is 0.01%. The density, the thermal conductivity and the rheological behavior of the nanofluid are experimentally investigated in order to evaluate the thermal resistance and the pumping power in microchannel under laminar flow. An analytical approach of optimization scheme was applied; it is compiled from a systematic thermal resistance model as an analysis method and the elitist non-dominated sorting genetic algorithm (NSGA2). The effects of the temperature, the channel aspect ratio, the channel wall ratio and the use of aqueous carbon nanotubes based nanofluid on the thermal resistance and the pumping power are investigated. The optimized results showed that use of the nanofluid as a working fluid reduce the total thermal resistance and can enhance significantly the thermal performances of the working fluid at high temperatures.