Improving leading edge cooling through transpiration with partitioned porous injectors and a jet

Abstract

This study proposes a novel transpiration cooling layout that improves the cooling effect in the stagnation region and downstream zones for a sharp leading edge. Large-eddy simulation is conducted using our in-house recursive-regularized thermal lattice Boltzmann method (RR-TLBM) and high-resolution grids with 2.33 × 108 nodes. The RR-TLBM method shows low numerical dissipation, which is crucial in studying the transpiration-cooled leading edge with small-scale flow structures. A proper size of transpiration area in a single porous injector can extend the effective cooling area, with about 62.2 % of the wall area cooled at the same coolant consumption. Moreover, the opposing jet can reduce the local heat flux in the stagnation region, especially for the sharp leading edges. The proposed combinational cooling method shows an improvement of about 20 % in the cooling performance of the stagnation zone, while there is a 25 % improvement downstream of the stagnation region when compared to that of the porous layout with partitioned injectors. Furthermore, turbulent mixing can impair the improvement in cooling performance downstream, and the extended effective cooling area is related to low turbulent fluctuation. The RR-TLBM solver shows great potential in capturing the 3D coherent structures in the transpiration-cooled leading edge, based on high-resolution grids and a desktop-level computer with three Tesla V100 graphics processing units (GPUs).