摘要
阐述采用流动分析商业软件CFX-TASCflow求解Navier-Stokes方程并结合κ-ε紊流模型来改进轴流式水轮机水力设计的方法。多年来,在轴流式水轮机转轮研究方面作了大量的工作并取得了巨大的进步;然而,随着研究的深入,在提高机组的效率方面单从转轮本身考虑余地有限,除转轮以外,其它过流通道也必须进行充分研究。结合一个轴流式水轮机开发项目,首先通过流动数值模拟研究了半蜗壳内的流动,提出了数值液流角、损失以及流量分配的概念对改进设计非常重要。在蜗壳优化的基础上,进一步指出:由于半蜗壳自身的特点,仅通过改变蜗壳的形状不可能实现固定导叶进口完美的流动结构,并在这种思想下,讨论了采用不同形状的固定导叶以减小固定导叶进口损失来弥补半蜗壳自身的不足,提高水力效率。还优化了一个五叶片的转轮。最后,在最优工况对全通道进行了数值模拟并预估了性能,对两个转轮在优化后的同一通道下进行了同台对比试验。
Describes improving design methods use commercial software CFX-TASC flow to solve Navier-Stokes equations together with κ-εturbulence model in the Kaplan Turbine.Great progress has been made in research of Kaplan turbine runner in the past years.However,We find some different with the further research in improving units efficiency;Other flow passage should be taken consideration except for runner.In present research,firstly,We studied a semi-spiral in a special topic by flow numerical simulation.The concepts of flow angle and energy loss as well as flowrate distribution are very important to improve design.Then,it is impossible to make very good flow pattern in inlet of stay vane only by means of changing geometry of spiral casing.Different geometry of stay vanes applied to reduce loss is discussed,so as to compensate the lack of spiral casing and improve hydraulic efficiency.Also an optimization of a runner with five blades is carried out.Finally,numerical performance are predicted at optimal operating points for entire turbine.Energy performance are compared between optimizde and original geometry in the same test stand in the case of any change of other flow passage.
出处
《东方电气评论》
2005年第1期1-7,17,共8页
Dongfang Electric Review
