Second Law Analysis of Nanofluid Flow within a Circular Minichannel Considering Nanoparticle Migration

Abstract

In the current research, entropy generation for the water-alumina nanofluid flow is studied in a circular minichannel for the laminar regime under constant wall heat flux in order to evaluate irreversibilities arising from friction and heat transfer. To this end, simulations are carried out considering the particle migration effects. Due to particle migration, the nanoparticles incorporate non-uniform distribution at the cross-section of the pipe, such that the concentration is larger at central areas. The concentration non-uniformity increases by augmenting the mean concentration, particle size, and Reynolds number. The rates of entropy generation are evaluated both locally and globally (integrated). The obtained results show that particle migration changes the thermal and frictional entropy generation rates significantly, particularly at high Reynolds numbers, large concentrations, and coarser particles. Hence, this phenomenon should be considered in examinations related to energy in the field of nanofluids.

Heat transfer and entropy generation analysis of Cu-water nanofluid in a vertical channel

“…Bahiraei and Kazerooni (2016) studied entropy generation of a nanofluid in a circular minichannel under constant heat flux. They showed that particle migration modifies the thermal and frictional entropy generation rates, particularly at high Reynolds numbers and concentrations, and coarser particles.…”