Complete Characterization of a Highly Loaded Low Pressure Compressor at Different Reynolds Numbers for Computational Fluid Dynamics Simulations

Computational fluid dynamics (CFD) is nowadays extensively used for turbomachinery design and performance prediction. Nevertheless, compressors numerical simulations still fail in correctly predicting the stall inception and the poststall behavior. Several authors address such a lack of accuracy to the incomplete definition of the boundary conditions and of the turbulence parameters at the inlet of the numerical domain. The aim of the present paper is to contribute to the development of compressors CFD by providing a complete set of input data for numerical simulations. A complete characterization has been carried out for a state-of-art 1.5 stage highly loaded low-pressure compressor for which previous CFD analyses have failed to predict its behavior. The experimental campaign has been carried out in the R4 facility at the Von Karman Institute for Fluid Dynamics (VKI). The test item has been tested in different operative conditions for two different speed lines (90% and 96% of the design speed) and for two different Reynolds numbers. Stable and unstable operative conditions have been investigated along with the stalling behavior, its inception, and the stall-cell flow field. Discrete hot-wire traverses have been performed in order to characterize the spanwise velocity field and the turbulence characteristics.