Effects of yarn architecture on local heat flux distribution in a ceramic matrix composite vane leading edge

Heat transfer in heterogeneous anisotropic composites is governed not only by effective thermal conductivity, but also by the organization of local heat flux pathways. In yarn-reinforced ceramic matrix composites (CMCs), high-conductivity yarns can redistribute conductive transport between the yarn and matrix phases, whereas conventional quantities such as temperature-gradient magnitude and local heat flux vectors provide limited information on how such redistribution relates to the global conduction task. This study presents a reference-based analysis for quantifying yarn-induced heat flux reorganization in CMCs. A geometrically identical homogeneous matrix model is used as the baseline, and its volume-averaged heat flux vector is adopted as a first-order macroscopic conduction reference. Two descriptors, Excess Deviation (ED) and Directional Deviation (DD), are defined to evaluate the overall vector deviation and directional alignment of local heat flux relative to this reference. The analysis is applied to a ceramic matrix composite vane leading-edge model containing 2D woven, 0° ply-stacked, and 45° ply-stacked yarn architectures. The results show that the 2D woven architecture produces broader matrix conductive-burden relief through continuous in-plane conductive pathways and yarn-undulation-induced through-thickness coupling. In contrast, ply-stacked architectures mainly localize heat flux reorganization near yarn layers, leaving interlayer matrix regions with stronger conductive burden. The 45° ply-stacked configurations achieve similar overall heat-transfer performance to the 0° configurations with a lower yarn volume fraction. These results clarify how yarn architecture controls local heat flux pathway organization and matrix conductive-burden redistribution in a curved CMC vane leading edge.