Heat transfer and flow characteristics of a rectangular channel with V-split protrusions

Heat transfer enhancement structures featuring high efficiency and low flow resistance can markedly boost the convective heat transfer performance of turbine blade internal cooling channels. This study proposes a novel heat transfer enhancement structure termed the V-split protrusion (VSP), and the flow and heat transfer mechanisms in a rectangular channel equipped with VSPs are investigated via numerical simulation. The effects of relative split position (s/D = 0.10–0.25), split divergence angle (θ = 0°–50°), and split inclination angle (α = 0°–75°) on the flow field structure and overall thermal performance factor (TPF) of the VSP structure are studied. Results show that the VSP outperforms spherical dimples (SDs), spherical protrusions (SPs), and split protrusions (StPs) in both TPF and heat transfer uniformity. With an increase in s/D, θ, and α, the vortex size at the trailing edge of the VSP gradually expands, and the downstream fluid adheres better to the wall. Therefore, the increase in s/D, θ, and α is conducive to improving the heat transfer performance of the VSP. Within the range of studied structural parameters, the VSP with s/D = 0.20, θ = 45°, and α = 75° demonstrates the optimal TPF. At a Reynolds number of 100,000, the average Nusselt number of the VSP is enhanced by 20.6%, 60.4%, and 33.2% compared with those of the SP, SD, and StP, respectively, with the TPF correspondingly improved by 16.1%, 30.5%, and 26.2%.