Large-Eddy Simulations of a 3 Stages High-Speed Low-Pressure Turbine Cascade

Abstract Compact high-speed low-pressure turbines allow to increase the performance of engines with respect to conventional low Mach and Reynolds numbers turbines. The flow in low-pressure turbine passages is extremely sensitive to unsteadiness, including background turbulence and deterministic unsteadiness induced by potential effects and wakes. Losses are primarily due to wall phenomena (profile losses) where transition is critical. Wakes as well as secondary flows have also non-negligeable contributions to losses and can be promoters for transition. Efforts need to be done to characterize turbulence in high-speed low-pressure turbines to adapt industrial design tools based on empirical data as well as RANS modeling. This study proposes the generation of high-fidelity databases with wall-resolved Large-Eddy Simulations of a CFD friendly 3 stages high-speed low-pressure turbine to calibrate URANS methods. To limit the CPU cost while keeping the physics of interest, the periodicity of each row of blade is set to one passage and only the mid-vein part is simulated in order to remove secondary flow effects. After defining a proper numerical strategy, the focus is on the effect of the inlet turbulence intensity on the flow and turbulence development all along the machine and the quantification of associated losses.