Numerical simulation of a parabolic solar collector equipped with a vortex generator under the influence of a magnetic field containing a two-phase hybrid nanofluid

Document Type : Original Article

Authors

1 Faculty of Mechanical Engineering University of Kashan, Kashan, Iran

2 Faculty of Mechanical Engineering, University of Kashan,, Kashan,, Iran

Abstract

In the present study, the effect of vortex generators in a parabolic solar collector is investigated. In the inner tube, vortex generators are placed in the flow path. Different geometric shapes of vortex generators on the flow behavior are investigated. In this study, in order to better utilize the effect of the magnetic field, Hartmann numbers 25 to 125 are applied to the parabolic solar collector. The two-phase hybrid nanofluid Cu-DWCNT/Therminol VP-1 is simulated as the working fluid at volume fractions of 0, 1, and 4%. The study is carried out for turbulent flow regime and Reynolds numbers 15,000 to 33,000. The Cu-DWCNT/Therminol VP-1 two-phase hybrid nanofluid enters the outer tube at a temperature of 70 degrees Celsius and the inner tube at a temperature of 23 degrees Celsius. Also, in order to solve the turbulent flow and discretize the equations, the K-Omega SST turbulence model and the Simple C algorithm have been used, respectively. The results obtained show that with increasing Reynolds number, heat transfer is affected and increases. In fact, with increasing Reynolds number, the flow velocity of the Cu-DWCNT/Therminol VP-1 two-phase hybrid nanofluid increases and as a result, the average Nusselt number increases. At a volume fraction of 4% of the Cu-DWCNT/Therminol VP-1 two-phase hybrid nanofluid and a Reynolds number of 33,000, the addition of a vortex generator (Case F geometry) inside the parabolic trough solar collector increases the average Nusselt number by 65.83% compared to the case without a vortex generator inside the parabolic trough solar collector. Finally, the exergy efficiency increases with the Hartmann number increasing from 25 to 125.

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