Investigation of thermal behavior and performance of different microchannels: A case study for traditional and Manifold Microchannels

Abstract

In this study, numerical investigation of forced convection of non-Newtonian nanofluid into Traditional Microchannel (TMC) and Manifold Microchannel (MMC) containing porous media is investigated. The bottom of the microchannel wall is kept at a constant temperature and the other walls are heat insulated. The inside of the microchannel is filled with porous media. This study addresses a new sample of microchannels (MMC and TMC) filled with porous material in a three-dimensional flow. The results show that increasing the Reynolds number and volume fraction of nanoparticles (φ) and decreasing the porosity, lead to heat transfer improvement. At low Reynolds numbers, there is no relative advantage over TMC or MMC. Finally, it is concluded that to achieve the acceptable performance evaluation criterion PEC (PEC> 1) at porosity ε= 0.9, thermal conductivity ratio (γ) must be γ <0.9. When thermal conductivity of porous foam is considered low, PEC variations and heat transfer rates in the traditional microchannel are uniform. For TMC and MMC in the maximum Reynolds number, the percentage of increase in heat transfer at ε= 0.9 compared to the absence of porous material is 13.5% and 26.26%, respectively. For MMC and TMC in minimum permeability and maximum Reynolds number, the percentage of reduction of heat transfer rate from n = 0.5 to n = 1.5 is equal to 0.86% and 0.37%, respectively.