An efficient transient simulation procedure for the reliable estimation of draft tube losses in the hydraulic design process

29th IAHR Symposium on Hydraulic Machinery and Systems

Weber, Paul^1 ; Jester-Zürker, Roland^1

Voith Hydro Holding GmbH and Co. KG, Alexanderstr. 11, Heidenheim

89522, Germany^1

关键词: Accurate prediction;    Adverse pressure gradient;    Computational domains;    Hydraulic designs;    Hydraulic machines;    Reliable results;    Simulation methodology;    Transient simulation;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/240/7/072017/pdf
DOI  :  10.1088/1755-1315/240/7/072017

来源: IOP

【 摘 要 】

Draft tube flow plays a significant role for the overall performance of a hydraulic machine and requires therefore special attention in the design process. However, as it is characterized by complex flow phenomena like swirl, adverse pressure gradients and flow separation, accurate predictions are challenging. Though the required technologies like transient simulation techniques and adequate turbulence modeling are available, it is especially the tremendous time consumption that renders the according analysis infeasible for the hydraulic design process. In this contribution a new simulation methodology is presented that accelerates transient simulations in three ways. Firstly, the computational domain is significantly reduced by substituting the distributor with appropriate boundary conditions. Secondly, it is shown by a grid study that meshes with intermediate resolutions are to be favored over massively refined grids. And thirdly, a timestep study uncovers potential for increased step sizes. The proposed methodology is validated by comparison to PIV measurements performed by Frey et al. (IOP Conf. Ser.: Earth and Env. Sci. 49 082007), thus demonstrating that the developed workflow yields accurate and reliable results.