Mohammednour Gibreel, Ali Mohammed Adam Jamei, Abdalazeem Adam, Hosham Wahballa, Abbasali Abouei Mehrizi, Hisham Elmouazen
• 1.25 mm single-row ribs reduce peak wall temperature by 13.67% vs smooth channels. • Double-row ribs boost mixing but increase flow resistance, reducing net gains. • 1.25 mm single-row ribs give best η (21.9% gain) vs smooth channels. • Cylindrical ribs reduce thermal stratification by 30% in rocket cooling. The thermal protection of rocket engine combustion chambers presents a critical challenge in supersonic flight applications. This study numerically investigates the enhancement of heat transfer and coolant flow characteristics in regenerative cooling channels through cylindrical rib integration, employing ANSYS Fluent with SST k-ω turbulence modeling to evaluate single- and double-row configurations (0.75-1.25 mm diameter) under supercritical hydrogen conditions (3 MPa, 300 K inlet). Results demonstrate that rib-induced turbulence disrupts thermal boundary layers, with a 1.25 mm single-row design achieving a 13.67% reduction in peak wall temperature compared to smooth channels, while double-row arrangements show diminishing returns due to increased flow resistance. The thermal performance factor (η = (Nu/Nu ₀ )/(f/f ₀ ) 1/3 ) reveals Case 3′s superiority (21.88% improvement over the smooth channel configuration) in balancing heat transfer enhancement against pressure drop penalties (9.23-20.93% for single-row, 8.26-18.7% for double-row). Notably, density-driven flow acceleration near heated walls mitigates pressure losses through localized viscosity reduction. Furthermore, cylindrical ribs reduce thermal stratification by up to 30% in single-row configurations, with double-row designs providing additional temperature homogenization at the cost of increased flow resistance. These findings offer critical insights for optimizing rib-enhanced cooling systems in high-performance rocket engines, achieving simultaneous thermal efficiency and hydraulic performance improvements.