Unsteady Half Annulus Computational Fluid Dynamics Calculations of Thermal Migration Through a Cooled 2.5 Stage High Pressure Turbine

Abstract

This paper presents an industrial perspective on the potential use of multipleairfoil row unsteady computational fluid dynamics (CFD) calculations in highpressure turbine design cycles. A slidingmesh unsteady CFD simulation is performed for a highpressure turbine section of a modern aviation engine at conditions representative of engine takeoff. The turbine consists of two stages plus a centerframe strut upstream of the lowpressure turbine. The airfoil counts per row are such that a halfannulus model domain must be simulated for periodicity. The total model domain size is 170 MM computational grid points and the solution requires approximately nine days of clock time on 6288 processing cores of a Cray XE6 supercomputer. Airfoil and endwall cooling flows are modeled via source term additions to the flow. The endwall flowpath cavities and their purge/leakage flows are resolved in the computational meshes to an extent. The timeaveraged temperature profile solution is compared with static rake data taken in engine tests. The unsteady solution shows a considerable improvement in agreement with the rake data, compared with a steadystate solution using circumferential mixing planes. Passagetopassage variations in the gas temperature prediction are present in the 2nd stage, due to nonperiodic alignment between the nozzle vanes and rotor blades. These passagetopassage differences are quantified and contrasted.