期刊名称：IOP Conference Series: Earth and Environmental Science
印刷版ISSN：1755-1307
电子版ISSN：1755-1315
出版年度：2019
卷号：240
期号：7
页码：1-11
DOI：10.1088/1755-1315/240/7/072017
出版社：IOP Publishing
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.
