Numerical and Experimental Investigation of Turning Flow Effects on Innovative Pin Fin Arrangements for Trailing Edge Cooling Configurations

摘要

The effect of the array configuration of circular pin fins is investigated from a numerical and experimental point of view reproducing a typical cooling scheme of a real high pressure aero-engine blade. The airstream enters the domain of interest radially from the hub inlet and exits axiallv from the trailing edge (TE) outlet section. More than 100 turbulators are inserted in the wedge-shaped IE duct to enhance the heat transfer: A reference array implementing seven rows of staggered pins is compared with an innovative pentagonal arrangement. Investigations were made considering real engine flow conditions: Both numerical calculations and experimental measurements were performed fixing Re = 18,000 and Ma =0.3 in the TE throat section. The effect of the tip mass flow rale was also taken into account, investigating 0% and 25% of the IE mass flow rate. The experimental activity was aimed at obtaining detailed heat transfer coefficient maps over the internal pressure side (PS) surface by means of the transient technique with thermo-chromic liquid crystals. Particle image velocimetry measurements were performed and surface flow visualizations were made by means of the oil and dye technique on the PS surface. Steady-state Reynolds averaged Navier-Stokes simulations were performed with two different computational fluid dynamics (CED) codes: the commercial software Ansvs CEa 11.0 and an in-house solver based on the opensource toolbox OpenEOAM~® to compare the performance and predictive capabilities. Turbulence was modeled by means of the k — to shear stress transport (SST) model with a hybrid near-wall treatment allowing strong clustering of the wall of interest as well us quite coarse refinement on the other viscous surfaces.