Aerodynamic Interactions Between a High Pressure Turbine and the First Low Pressure Stator

This paper presents a numerical study on the interaction between a single-stage high-pressure turbine and the first vane row of a low-pressure turbine at aerodesign conditions. It focuses on the simulation of the flow within the inter-turbine duct and the loss generated in the downstream low-pressure vane.Former experiments provided steady and unsteady measurements in the duct between the high and the low-pressure turbines and after the low-pressure nozzle. A 3D unsteady RANS approach with phase-lagged boundary conditions is used to characterize the unsteady periodic effects developing in the inter-turbine channel and downstream in the low-pressure vane.For the numerical study, two different configurations were considered: a single stage high-pressure turbine configuration and a high-pressure rotor coupled with a low-pressure vane. For the second one, two inlet boundary conditions are considered upstream of the rotor: a circumferentially uniform boundary condition and a circumferentially non uniform rotating boundary condition. The resulting flow fields are compared within the intermediate duct.A harmonic Fourier analysis is carried out to underline the effects of upstream and downstream stator and the interaction with the high-pressure rotor. An unsteady Adamczyk decomposition within a plane located in the duct showed the influence of the different components and the levels of unsteadiness. Comparisons with experimental data show a reasonable good agreement.Copyright © 2013 by ASME