Abstract
In the present study, highly resolved large-eddy simulations of a VKI LS-89 high-pressure turbine (HPT) blade (T. Arts et al., 1990) with spanwise end-walls are performed at a Reynolds number of 0.57 million and an exit Mach number of 0.9. Two different spanwise temperature profiles, one uniform as baseline and one asymmetric profile extracted at the combustor exit from the public literature, are set at the inlet boundary. The high-fidelity data generated by the present cases are analyzed to investigate the end-wall secondary features, and show that the vortical structures that form near the leading edge of the vane include pressure-side and suction-side legs. While the end-wall vortical structures show no obvious effects on the time-averaged behavior of the pressure-side blade boundary layer, the suction-side structures induce counter rotating vortical structures and trigger rapid transition in the end-wall boundary layers. Furthermore, the cases with different inlet temperature profiles are directly compared, and the effects of the inflow on the aerothermal performance of the HPT vane are discussed. Based on the recently proposed entropy loss analysis (Zhao and Sandberg, GT2019-90126), we have been able to quantitatively show that the end-wall effects contribute significantly to the total loss of the turbine, with the main contributors being the extra viscous dissipation and turbulence production in the end-wall boundary layer.
