Numerical Investigation of Thermal and Hydraulic Analysis of Grooved Channels in OTEC Systems: Influence of Geometric Ratios

ABSTRACT This study aims to enhance the efficiency of heat exchangers in Ocean Thermal Energy Conversion (OTEC) systems by investigating the influence of geometric parameters on heat transfer and fluid flow. Numerical simulations were performed under laminar flow conditions for a range of Reynolds numbers (50–250), incorporating key geometric parameters, such as aspect ratio (AR) and concave–convex ratio ( R ). A two‐dimensional computational model, validated against experimental and numerical benchmarks, employs the finite volume method for steady‐state analysis. Results demonstrate that higher AR values significantly enhance heat transfer efficiency, while lower R values increase localized heat transfer rates at the cost of greater pressure drops. Interestingly, the highest heat transfer efficiency is not observed in the configurations with the highest Nusselt number. Instead, it occurs in those that balance moderate heat transfer rates with reduced pressure drop, highlighting the interplay between thermal performance and flow resistance. Using machine learning, the importance of AR and R in determining Nusselt number and heat transfer efficiency is quantified, with AR identified as the most critical factor. Additionally, a correlation model is proposed for predicting thermal performance, reducing reliance on computational simulations. These findings provide actionable insights for optimizing heat exchanger designs, supporting the development of efficient and sustainable OTEC systems.