Numerical evaluation of exergy efficiency of innovative turbulators in solar collector filled with hybrid nanofluid

In the current study, the impact of two-phase water-Al₂O₃-MWCNT hybrid nanofluid in turbulent flow on exergy efficiency in a solar collector equipped with innovative turbulators is investigated numerically. To simulate two-phase nanofluid, the mixture model was employed, and to simulate radiation and turbulent flow, the surface-to-surface (S2S) method and standard k-ε model were utilized. The study is performed for two-phase water-Al₂O₃-MWCNT hybrid nanofluid in Reynolds numbers (Re) of 5000–20,000, volume fraction (φ) of 1–3%, torsion ratios of 0.05, 0.15 and 0.25 at heights of 5, 10, 15 and 20 mm made of innovative turbulator. According to the results, exergy efficiency decreases with increasing torsion and height ratio in innovative turbulators. The highest exergy efficiency occurs at the Re = 20,000 and φ = 0.03 at a torsion ratio of 0.05 and a turbulator height of 5 mm. Also, the lowest extrusion efficiency occurs in Re = 5000 and φ = 0.01 in torsion ratio of 0.25 and turbulator height of 19 mm. This is while the exergy efficiency in the solar collector with turbulator with a height of 5 mm and a torsion ratio of 0.25 in Re = 20,000 and φ = 0.03 by 6.04% compared to the solar collector with the same characteristics in the ratio the torsion decreases by 0.05.