Interaction of shrouded stator flow and main flow and its influence on performances of a three-stage high pressure compressor

Abstract

The prediction of the complex flows within a turbomachinery remains a challenging issue for computational fluid dynamics (CFD). The real features of a turbomachinery must be taken into account in the simulation but they increase its complexity. One of these features is the leakage flow due to the axial gap between the fixed and rotating parts of the hub. This article focuses on this flow within the scope of a high-pressure compressor. The results are compared with experimental data obtained in the main flow path. The leakage flow is characterized by several vortices, especially near the hub and between the seal-teeth. It interacts with the main flow: the hub separation is quite wider while the casing one is reduced in comparison with the smooth case. In this article, the smooth case is related to the simulation without any shrouded stator cavity. The leakage flow influences strongly on compressor performances. Taking into account the leakage flow in the CFD improves the agreement between CFD and experimental values. Due to the vortex prediction, the influence of the turbulence modelling is also assessed. The explicit algebraic Reynolds stress model improves the flow prediction while the presently investigated differential Reynolds stress model predicts too wide hub corner separation which leads to high underestimation of compressor performances.