ABSTRACT Enhancing the thermal efficiency of parabolic trough solar collectors (PTCs) is vital for optimizing concentrated solar power systems and industrial solar thermal applications. Conventional receiver tubes often suffer from limited internal heat transfer and uneven solar flux distribution, reducing energy conversion efficiency. This study presents a comprehensive numerical investigation of PTC receivers with modified tube geometries ‐circular, elliptical, and hexagonal‐integrated with internal helical turbulators. Optical performance was evaluated using Monte Carlo Ray Tracing (MCRT) to determine solar flux distribution and identify optimal receiver eccentricities, while thermal–hydraulic behavior was assessed via computational fluid dynamics (CFD) simulations over Reynolds numbers from 3000 to 11,000. Optimal eccentricities were determined as −12, −8, and −12 mm for circular, elliptical, and hexagonal tubes, respectively. The elliptical tube achieved the highest optical interception, with an average intercept factor of 80.13%. The introduction of helical turbulators significantly enhanced heat transfer, increasing Nusselt numbers by 31%, 45%, and 46% for circular, elliptical, and hexagonal tubes, respectively. Corresponding friction factor ratios ranged from 1.6 to 2.0, highlighting the trade‐off between heat transfer improvement and flow resistance. Overall, the elliptical receiver with a small‐pitch helical turbulator delivered the best combined thermo‐optical performance.
Suffer et al. (Mon,) studied this question.