湖南白渔潭水电站低水头转桨式转轮的优化设计

Optimal design of low-head adjustable-blade runner for Baiyutan Hydropower Station in Hunan

湖南大唐白渔潭水电站的7台水轮发电机组,由于下游水电站建成投入运行后,尾水位升高导致发电水头降低,致使原有机组运行区域恶化,出力减少。改造目标是在不改变蜗壳、尾水管、转轮室、导水机构等流道的前提下,仅通过更换转轮使出力由1.99 MW增加至2.316 MW,同时效率显著提高。本文介绍了利用CFD技术对转轮进行全新设计和优化分析的过程,并对计算方法以及内部流动、压力脉动、静应力、空化等计算做了分析,结果表明在水头9 m以下的运行范围内,优化后的新转轮,最高效率达到了93.7%,运行区域合理,同时压力脉动小、空化性能好,转轮静应力总体水平较低,技术指标满足合同要求,可以投入原型机生产制造。本文还对计算过程提出了一些看法。

As a result of the completion and operation of the downstream hydropower station, the tailwater level of the 7 hydrogenerator units at the Baiyutan Hydropower Station of Datang Group in Hunan rises, leading to the reduction of generating head and consequently the deterioration of original unit operating area and the reduction of unit output. For this reason, transformation is carried out to increase the output from 1.99 MW to 2.316 MW and significantly improve the efficiency only by replacing the runner without changing the spiral casing, draft tube, runner chamber, gate operating mechanism and other flow passages. This paper introduces a brand-new process of runner design and optimization analysis using CFD technology, and analyzes the calculation method, internal flow, pressure pulsation, static stress and cavitation. The results show that the optimized new runner has a maximum efficiency of 93.7% within the operating head range of less than 9 m, with a reasonable operating area, small pressure pulsation, good cavitation performance, low static stress of runner, and satisfactory technical indicators to the contract requirements, so the runner can be put into prototype production. In addition, this paper also presents some views on the calculation process.