Experimental study of rib height and pitch effects on thermal-hydraulic performance in gas turbine cooling at high Reynolds numbers

This study presents an experimental investigation into the thermal-hydraulic performance of 45° broken V-shaped rib turbulators within square internal cooling channels under ultra-high Reynolds number conditions ( Re = 100,000–400,000). The research systematically examines the effects of varying rib height-to-hydraulic diameter ratios (e/Dₕ = 1/10, 1/20, 1/25, 1/30) and pitch-to-height ratios (p/e = 12.5 and 4) on heat transfer enhancement and pressure drop characteristics. Local Nusselt numbers and friction factors were evaluated using infrared thermography (IR) and pressure measurements, enabling effective comparison of thermal-hydraulic performance across configurations. Findings indicate that the configuration with e/Dₕ = 1/25 and p/e = 4 achieves the highest THP across the tested Reynolds number range, balancing effective heat transfer augmentation with minimal pressure losses. Conversely, while the e/Dₕ = 1/10 configuration exhibits superior heat transfer rates, it incurs significant frictional penalties, reducing its overall efficiency. The results underscore the critical importance of optimizing rib geometry to enhance thermal performance without compromising hydraulic efficiency, offering valuable insights for the design of advanced cooling systems in high-performance gas turbine applications.