Numerical and experimental validation of Taguchi-optimized star-core fin inserts for enhanced thermal hydraulic performance factor

Enhancing heat transfer in compact thermal systems remains a key engineering challenge, where internal geometry plays a decisive role in disrupting flow, increasing surface exposure, and boosting convective efficiency. In this study, a novel star-core fin insert was developed, featuring angularly spaced radial fins mounted on a central rod to improve the thermal-hydraulic performance factor (THPF). The design was optimized using a hybrid approach that combined the Taguchi method with Computational Fluid Dynamics (CFD) simulations, enabling systematic evaluation of five geometric parameters: fin diameter, number of fin edges, number of fins per rod, fin thickness, and angular offset. These parameters were varied concurrently to capture interaction effects and identify the most effective configuration. The optimal configuration (Case 31) achieved a THPF of 1.75, representing a 75% improvement over the smooth pipe baseline, with a fin diameter of 14.5 mm, five edges, four fins per rod, a thickness of 3 mm, and a 0° angular offset. A physical prototype of the absorber tube was fabricated and tested experimentally, showing strong agreement with numerical predictions (correlation = 95.5%, RMSE = 4.5%). These findings demonstrate that the integrated optimization framework is reliable and effective, improving heat transfer performance while maintaining acceptable pressure losses. The proposed passive design offers a scalable and energy-efficient solution for next generation compact heat exchangers.