@Article{fhmt.2026.084530,
AUTHOR = {Yuzhang Wang, Zhuning Liu, Haozhe Sun, Zhuo Li, Kanru Cheng, Chaoran Yang},
TITLE = {Effect of Surface Roughness on Flow Behavior and Conjugate Heat Transfer between TBC and Cooling Film},
JOURNAL = {Frontiers in Heat and Mass Transfer},
VOLUME = {},
YEAR = {},
NUMBER = {},
PAGES = {{pages}},
URL = {http://www.techscience.com/fhmt/online/detail/27932},
ISSN = {2151-8629},
ABSTRACT = {During the operation of a gas turbine, the surface morphology of thermal barrier coatings (TBCs) of the high temperature blades inevitably evolves due to sintering, particle deposition or other factors, leading to an increase in surface roughness. This altered roughness can significantly influence the flow behavior of cooling films and the heat transfer performance of the coupled cooling film-TBC system. In this work, the flow behavior and conjugate heat transfer between cooling film and TBC under varying surface roughness conditions were investigated using the double distribution function lattice Boltzmann method (DDF-LBM) coupled with large eddy simulation (LES). The effects of surface roughness on the vortex structures, mean velocity profile, surface shear stress distribution, mean shear stress, surface temperature distribution, field synergy distribution, and mean heat transfer coefficient were analyzed. The results demonstrate that increased TBC surface roughness substantially enhances flow mixing, as evidenced by more widespread vortex distributions (identified by <mml:math id="mml-ieqn-1"><mml:mrow><mml:mi mathvariant="normal">Ω</mml:mi></mml:mrow></mml:math> criterion), modifications to the mean velocity profile, and increases in both the displacement and momentum thicknesses of the boundary layer. Moreover, surfaces with greater roughness exhibit more pronounced non-uniformities in shear stress and temperature distributions, which may induce cracking due to uneven mechanical loads and thermal stresses, thereby accelerating TBC degradation. The mean dimensionless surface temperature of the TBC increases by approximately 130%. Additionally, surface roughness augments heat transfer performance, with the convective heat transfer coefficient rising by up to 19.12%, and this phenomenon can be explained by the gradually saturated Field synergy distribution.},
DOI = {10.32604/fhmt.2026.084530}
}