Numerical thermal–hydraulic modeling and generalized roughness-function correlations for high-aspect-ratio single-sided ribbed channels

High-aspect-ratio cooling channels with single-sided rib roughness are increasingly used in wall-integrated turbine blade designs; however, generalized thermal–hydraulic scaling frameworks for such asymmetric multi-pass configurations remain limited, particularly for channels combining high aspect ratio, single-wall ribbing, turning regions, and engine-relevant Reynolds numbers. This study develops a validated numerical framework to investigate heat transfer and pressure loss in high-aspect-ratio nominally rectangular channels with one ribbed wall under non-rotating conditions. Reynolds–Averaged Navier–Stokes simulations with the SST turbulence model are benchmarked against experimentally measured geometries spanning the extremes of aspect ratio, rib topology, and guide-vane configuration, showing agreement within experimental uncertainty for heat transfer and total static pressure loss. The validated model is then extended using Latin Hypercube Sampling to construct a generalized CFD database spanning aspect ratios from 4 to 15, Reynolds numbers from 20,000 to 200,000, rib height-to-hydraulic-diameter ratios from 5%–20%, pitch-to-height ratios from 5 to 15, rib angles from 30° to 75°, three rib geometries, and two guide-vane configurations. V- and W-ribs exhibit comparable thermal–hydraulic performance, with closely overlapping overall thermal–hydraulic performance distributions, whereas staggered V-ribs yield consistently lower heat-transfer augmentation and reduced overall performance over a broad portion of the design space. Aspect ratio primarily alters dimensional heat-transfer and pressure-loss levels, with limited influence on normalized quantities. Rib height increases normalized friction significantly while producing only moderate gains in heat transfer, whereas increasing pitch reduces friction and yields a mild improvement in overall performance. Rib angle enhances heat transfer in straight passages but increases friction more strongly, while in bends it produces a weaker but favorable trade-off. Guide-vane configuration has negligible influence on downstream straight passages but strongly affects bend performance, with 135° vanes increasing both heat transfer and losses relative to 180° designs. Unlike prior studies focused primarily on square or moderate-aspect-ratio channels with multi-wall ribbing, the present work develops generalized roughness-function scaling specifically for high-aspect-ratio single-sided ribbed multi-pass channels. The resulting database is condensed into generalized roughness-function correlations for friction (R) and heat transfer (G), achieving mean absolute percentage errors of approximately 6.8–10.6% and 9.2–14.3%, respectively. These correlations provide predictive capability for high-aspect-ratio single-sided ribbed channels within the investigated design envelope.