Two-phase nanofluid flow simulation with different nanoparticle morphologies in a novel parabolic trough solar collector equipped with acentric absorber tube and insulator roof

Abstract

The main objective of the present work is to investigate the morphology effects of Syltherm 800 oil-based γ-AlOOH nanofluid on performance evaluation criterion (PEC) and energy efficiency of a novel parabolic trough solar collector (PTSC) numerically using finite volume method. The other goal is to compare the obtained results of nanofluid simulation in PTSC using single-phase mixture model (SPM) with two-phase mixture model (TPM). In addition, influences of using acentric absorber tube are determined. Consequently, in this step the optimum configuration is introduced and then different nanofluids characteristics such as volume fractions, nanoparticles diameters and shapes on the optimum configuration are investigated. Based on the obtained results, for all studied cases, obtained PEC and energy efficiencies employing the TPM in nanofluid simulation are more than that SPM simulation. Using the novel PTSC leads to the higher average Nusselt number, energy efficiency, PEC and outlet temperature at all Reynolds numbers. For all cases, the PEC and energy efficiency increase by reduction of nanoparticle volume fraction and diameter. As the Reynolds number increases, the energy efficiency of PTSC increases for all studied cases till Reynolds number equal to 5000 and then always reduces. Therefore, the optimum Reynolds number is 5000. The optimum morphology is related to the nanoparticles shape of blade which is followed by the brick, cylinders and platelet, respectively.