Detailed Convective Heat Transfer at the Endwalls of Pin Fin, Body-Centered Cubic, Tetrakaidecahedron, and Octet Lattice-Based Cooling Channels

Abstract

Abstract. This study presents detailed endwall convective heat transfer measurements for four lattice topologies—pin fins, body-centered cubic (BCC), tetrakaidecahedron (TKD), and octet—arranged in inline configurations within a square duct. Each topology was tested in two configurations: continuous and discretely placed unit cells along the flow direction, resulting in a total of eight test articles. The transient liquid crystal thermography technique has been employed to determine the local convection heat transfer coefficient resulting from the sole contribution of fluid dynamics in lattice-based channels. The test articles were additively manufactured in a low thermal conductivity and low thermal diffusivity resin and installed in a duct (aspect ratio 1:1) representative of the mid-chord region of high-pressure turbine blades. Experiments were conducted for Reynolds numbers between 10,000 and 30,000. Heat transfer results are presented as normalized Nusselt number maps and spanwise-averaged profiles, revealing periodicity in the unit cell's thermal performance. TKD and octet topologies exhibited the highest convective heat transfer, while BCC demonstrated superior thermal-hydraulic performance. These results offer valuable benchmarks for computational studies using periodic boundary conditions in fluid-only domains.