Investigating the effect of element shape of the face-centered cubic lattice structure on the flow and endwall heat transfer characteristics in a rectangular channel

Experimental and numerical methods were utilized to investigate the effect of element shape of the facecentered cubic (FCC) lattice structure on the flow and endwall heat transfer characteristics in a rectangular channel. The porosity of the FCC lattice structure is identical (0.92), while the three different element shapes are circular, rectangular and elliptical. The results reveal that, due to the existence of cross-tilted ligaments of the FCC lattice, more fluid flows towards the endwall region, and periodic acceleration and deceleration of the fluid occur in the free flow passage, which induces an alternation of heat transfer enhancement and weakening. Meanwhile, the peak of heat transfer appears around the second row of vertices, and the averaged heat transfer enhancement produced by FCC lattices is, at least, 3 times higher than that of a smooth channel. The heat transfer performance of the elliptical FCC lattice and the rectangular FCC lattice is respectively 27%-31% and 25%-26% higher than that of the circular FCC lattice at the same Reynolds number, which is due to the larger cross-section size of their ligaments in the flow direction. Considering the trade-offs between heat transfer and pressure drop, the circular FCC lattice exhibits the highest overall heat transfer efficiency. (C) 2020 Elsevier Ltd. All rights reserved.