The Impact of Multi-Scale Ceramic Matrix Composite Roughness on Heat Transfer and Boundary Layer Behavior

Peter H. Wilkins, Stephen P. Lynch, Karen A. Thole

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations


Ceramic Matrix Composites (CMCs) can enable more efficient gas turbines relative to traditional nickel alloys resulting from enabling higher turbine entry temperatures that in turn benefit cycle performance. One negative effect of adding CMCs to the hot section is the introduction of a unique surface roughness due to the underlying weave topology. This surface roughness is generally at a macro scale compared with traditional turbine roughness such as deposits or erosion, which are well known to interact with the boundary layer development and increase convective heat transfer. In this study, scales representative of traditional turbine roughness in combination with macro scale weave roughness is investigated for convective heat transfer augmentation and boundary layer behavior. In addition to investigating the impact of the CMC roughness scales, 5 harness satin and twill weave patterns are studied to understand the differences between weaves. Heat transfer measurements are conducted in scaled up wind tunnel tests using a conjugate steady state analysis with freestream turbulence intensities of 0.5% and 24%. Boundary layer behavior is measured using Particle Image Velocimetry to capture cross-stream and streamwise planes. Compared to the 00 5 harness satin surface, the twill surface has higher Stanton number augmentation, owing to the increased number and high density of flow facing features that disrupt the boundary layer. Additionally, the large-scale weave roughness and traditional small-scale turbine roughness act largely independent of one another.

Original languageEnglish (US)
Title of host publicationHeat Transfer - General Interest/Additive Manufacturing Impacts on Heat Transfer; Internal Air Systems; Internal Cooling
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Electronic)9780791887011
StatePublished - 2023
EventASME Turbo Expo 2023: Turbomachinery Technical Conference and Exposition, GT 2023 - Boston, United States
Duration: Jun 26 2023Jun 30 2023

Publication series

NameProceedings of the ASME Turbo Expo


ConferenceASME Turbo Expo 2023: Turbomachinery Technical Conference and Exposition, GT 2023
Country/TerritoryUnited States

All Science Journal Classification (ASJC) codes

  • General Engineering

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