Improvement of the energy and exergy efficiencies of the parabolic solar collector equipped with a twisted turbulator using SWCNT-Cu/water two-phase hybrid nanofluid

Abstract

In the present numerical study, the effect of twisted turbulator on the improvement of energy and exergy efficiencies and hydraulic performance of SWCNT-Cu/water hybrid nanofluid in a solar collector is evaluated using computational fluid dynamics and ANSYS-FLUENT software. In this study, SOLIDWORKS software is employed to draw the geometry of the solar collector. Since the fluid flow in the solar collector is turbulent, the SST k-ω turbulence model is used. In addition, a mixed two-phase model is employed to model the hybrid nanofluid. The study is performed for Reynolds numbers (Re) in the range of 9000 to 36000, volume fractions (φ) of 1 to 3%, and turbulator pitch ratios (PR) of 1, 2, 3, and 4. It can be concluded that the average Nusselt number and the pressure drop are ascending functions of φ and Re. Also, the amount of pressure drop and the average Nusselt number is enhanced with the PR. At φ = 3% and Re = 36,000, the twisted turbulator with PR = 4 intensifies the average Nusselt number by 74.95% compared to the solar collector without turbulator. At φ = 3% and Re = 36,000, the twisted turbulator with PR = 4 enhances the pressure drop by 429.31% compared to the solar collector without turbulator. In a solar collector with a twisted turbulator with PR = 4 and φ = 3%, the amount of energy efficiency is enhanced by 41.75% by enhancing the Re from 9000 to 36000. In a solar collector with a turbulator with PR = 1 and φ = 3%, the amount of exergy efficiency is enhanced by 33.09% by intensifying the Re from 9000 to 36000.