CFD Analysis of Hybrid Ionanofluid Flow in a Parabolic Trough Solar Collector With Helically Finned Absorber Pipe

The increasing global demand for sustainable energy emphasizes the need for improved solar thermal technologies. Parabolic trough solar collectors (PTSCs) in concentrating solar power systems face limited thermal efficiency due to suboptimal heat transfer fluids (HTFs) and outdated absorber designs. Traditional fluids, such as water or oils, have low thermal conductivity, limiting heat absorption and transfer. Smooth absorber tubes also fail to optimize fluid interaction. This model presents a comprehensive computational fluid dynamics (CFDs) analysis of hybrid ionanofluid flow in a PTSC equipped with an axial helically finned absorber pipe for better thermal conductivity, stability, and to enhance convective heat transfer. The working fluid is composed of boron nitride (BN) and nanodiamond (ND) nanoparticles dispersed in 1,3‐dimethylimidazolium methyl phosphonate (DIMIM(MeO)(H)PO 2 ). The partial differential mathematical model is solved using the finite element technique. Results show that increasing solar irradiation from 300 to 1100 W/m 2 at a constant inlet temperature of 298 K and 1% nanoparticles concentration enhances thermal efficiency by 11.96%. Additionally, increasing the nanoparticles volume fraction from 0% to 2% significantly improves thermal performance. At an inlet velocity of 0.006 m/s ( Re = 9.3), with a fixed solar input of 900 W/m 2 and an inlet temperature of 298 K, the system shows a 3.36% improvement in efficiency. Among various BN:ND mixing ratios (0:100, 25:75, 50:50, 75:25, and 100:0) at a total 1% concentration, the 25:75 BN:ND ratio yields the highest thermal efficiency. Including internal helical axial fins in the absorber tube enhances heat transfer by increasing surface area, improving convective heat transfer, and lowering thermal resistance. The synergistic effects of fin‐induced turbulence and the superior thermophysical properties of the hybrid ionanofluid—its high specific heat and thermal conductivity significantly enhance the thermal efficiency of the PTSC, surpassing systems that utilize conventional smooth absorber tubes.