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.

elsA-Hybrid: an all-in-one structured/unstructured solver for the simulation of internal and external flows. Application to turbomachinery

“…Figure 15b shows a close-up of the middle region of the cavity. These results are in agreement with the observations of Marty et al [25] who performed similar simulations using a fully structured grid. The evolution of the residuals is shown in Figs.…”

Improved compressor corner separation prediction using the quadratic constitutive relation

“…16 The primary interest of using ASM is to avoid the cost and difficulties in solving the RSM, and better results have been reported for turbomachinery case where the flow has strong secondary flow and curvature. 17 However, the general experience is that these benefits are hard to realize. First, ASM equations are coupled nonlinear equations and it is nontrivial to get the root economically.…”

Multiple-Frequency Phase-Lagged Unsteady Simulations of Experimental Axial Compressor

“…On the total temperature distribution, all of the calculations overestimate the casing wall temperature. The purpose of this work is not to attempt to explain discrepancies between CFD and experiments, which is always a difficult task since discrepancies can be explained by many factors (unrealistic boundary conditions, geometrical details not taken into account [33], turbulence modelling, grid density, numerical errors, etc.) The important messages to deliver here are that, on this compressor configuration for the analyzed operating point, the following statements are true: 1) A very close agreement is obtained between the MFA and RC computations, in particular concerning the shapes and the levels of the radial distributions, which are well reproduced.…”