Numerical investigation of draft tube flows using a hybrid RANS-LES turbulence model and a low-dissipation scheme

29th IAHR Symposium on Hydraulic Machinery and Systems

Yang, L.^1 ; Jiang, Y.^1 ; Nadarajah, S.^1

McGill University, 817 Sherbrooke Street West, Montreal

QC

H3A 0C3, Canada^1

关键词: Adaptive simulation;    Best efficiency point;    Low dissipations;    Numerical investigations;    Numerical results;    SST turbulence models;    Transient simulation;    Turbulent structures;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/240/7/072011/pdf
DOI  :  10.1088/1755-1315/240/7/072011

来源: IOP

【 摘 要 】

Hydro-turbines are operated at loads above or below the best efficiency point (over- or part-load), where turbulent flow structures are formed in the draft tube. The goal of the project is to investigate complex turbulent structures present in the draft tube through a thorough numerical investigation. In the context of numerical simulations, a focus is made on the turbulence model and the numerical scheme. Transient simulations with the k-ω SST and SAS (Scale Adaptive Simulation)-SST turbulence models are applied with a novel eddy-preserving limiter scheme for draft tube flows. The application of both the SAS-SST turbulence model and the eddy-preserving limiter scheme allows for the resolution of more turbulent structures. The impact of the inlet modification is also studied. Numerical results are validated through a comparison to experimental data for the BulbT test case.