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

Abstract

The accurate prediction of turbines performance and flow fields requires the assessment of unsteady numerical simulations. This paper presents a numerical study on the interaction between a singlestage highpressure turbine and the first vane row of a lowpressure turbine. It focuses on the simulation of the flow within the interturbine duct and the loss generated in the downstream lowpressure vane. Former experiments provided steady and unsteady measurements in the interturbine duct and after the lowpressure vane. A 3D unsteady Reynoldsaveraged Navier–Stokes (URANS) approach with phaselagged boundary conditions is used to characterize the unsteady periodic effects in the interturbine channel and downstream in the lowpressure vane. For the numerical study, two different configurations are considered: a singlestage highpressure turbine configuration and a highpressure rotor coupled with a lowpressure vane. For the second one, two inlet boundary conditions are implemented upstream of the rotor: a circumferentially uniform boundary condition and a circumferentially nonuniform 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 the highpressure rotor. An unsteady Adamczyk decomposition of the flow field within the duct gives the influence of the different components and the levels of unsteadiness. Comparisons with experimental data show a reasonable good agreement.