The influence of the geometric shape of the symmetrical twisted turbulator on the performance of parabolic solar collector having hybrid nanofluid: Numerical approach using two-phase model

In this investigation, the influence of twisted turbulator and water-based MWCNT-MgO hybrid nanofluid on thermal-hydraulic performance (PEC), energy efficiency (eta(n)), and exergy efficiency (eta(ex)) of parabolic solar collectors (PSCs) was numerically investigated using the finite volume process. The two-phase nanofluid flows at the Reynolds number (Re) ranging of 10,000-25,000, the RNG k-epsilon turbulence model is used to model the turbulent flow regime. The nanofluid is modeled by a two-phase mixed model. In addition, the SIMPLEC algorithm was used for simulation. The study is performed for nanoparticles concentrations (phi) of 1% to 3% and pitch ratios (PR) of 0.25, 0.5, 0.75, and 1. Re and phi of MWCNT and MgO nanoparticles were detected to augments (Nu(av)). It is detected that the values of PEC are more than 1 for all cases. Therefore, it can be concluded that using a twisted turbulator and an enhancement of its PR intensifies PEC. In addition, the results demonstrate that eta(n) is enhanced and eta(ex) is reduced with the PR of the solar collector having twisted. For case of phi = 3%, as Re increased from 10,000 to 25,000, eta(n)and eta(ex) are enhanced by 45.98% and 31.67% for PR = 1 and 0.25, respectively.