Numerical Investigation of Turbulent Flow through Rectangular and Biconvex Shaped Trash Racks

• 作者: Hans O. ?kerstedt Sebastian Eller T. Staffan Lundstr?m
• 来源期刊: 工程(英文)(1947-3931)
• 学科: 医学
• 关键词: Trash Racks Head Loss TURBULENCE CFD HYDROPOWER FISH Migration
• 年，卷（期）: 2017,（5）
• 页码范围: 412-426
• 页数: 15页
• 分类号: R73

摘要

Turbulent flow through a trash rack of bars of rectangular and biconvex shapes is considered. A trash rack is composed of an array of bars fitted into a hydro-electric power station to prevent debris and fish to enter the waterway towards the turbine. The work is directed towards modeling a large number of bars for which the flow turn out to have a periodic structure. It is here shown that this case can be simplified with the flow past a single bar together with periodic boundary conditions. Using this approach the head loss is derived for different angles of attack α and blockages P for two shapes of the rack, a rectangular bar and an aerodynamically shaped biconvex bar. It is found that overall loss of the biconvex bars is in general about 15% of the loss for the rectangular case for small angles of attack. For large angle of attack this difference diminishes. Of interest for the biconvex bars is also a local minimum in the head loss for angles approximately greater than 20°and for a blockage P around 0.35. This combination of parameters gives a low loss together with an efficient barrier for debris and fishes.