Evaluation of near-wall solution approaches for large-eddy simulations of flow in a centrifugal pump impeller. Issue 1 (1st January 2016)

• Record Type: Journal Article
• Authors: Yao, Zhi-Feng; Yang, Zheng-Jun; Wang, Fu-Jun
• Is Part Of: Engineering applications of computational fluid mechanics. Volume 10:Issue 1(2016)
• Page Start: 452
• Page End: 465
• Publication Date: 2016-01-01
• Subjects: large-eddy simulation -- near-wall solution -- evaluation -- centrifugal pump impeller; Computational fluid dynamics -- Periodicals; 620.10640285
• DOI: 10.1080/19942060.2016.1189362
• Languages: English
• ISSNs: 1994-2060

Abstract

ABSTRACT: The turbulent flow in a centrifugal pump impeller is bounded by complex surfaces, including blades, a hub and a shroud. The primary challenge of the flow simulation arises from the generation of a boundary layer between the surface of the impeller and the moving fluid. The principal objective is to evaluate the near-wall solution approaches that are typically used to deal with the flow in the boundary layer for the large-eddy simulation (LES) of a centrifugal pump impeller. Three near-wall solution approaches –the wall-function approach, the wall-resolved approach and the hybrid Reynolds averaged Navier–Stoke (RANS) and LES approach – are tested. The simulation results are compared with experimental results conducted through particle imaging velocimetry (PIV) and laser Doppler velocimetry (LDV). It is found that the wall-function approach is more sparing of computational resources, while the other two approaches have the important advantage of providing highly accurate boundary layer flow prediction. The hybrid RANS/LES approach is suitable for predicting steady-flow features, such as time-averaged velocities and hydraulic losses. Despite the fact that the wall-resolved approach is expensive in terms of computing resources, it exhibits a strong ability to capture a small-scale vortex and predict instantaneous velocity in the near-wall region in the impeller. The wall-resolved approach is thus recommended for the transient simulation of flows in centrifugal pump impellers.