水利学报2023，Vol.54Issue(12)：1464-1472,9.DOI:10.13243/j.cnki.slxb.20230364
混流式水轮机卡门涡致振机理探讨与分析
Exploration and analysis of the mechanism of Karman vortex induced vibration in Francis turbine
摘要
Abstract
Karman vortices in hydraulic turbines may generate vibration and other issues.Strong Karman vortex frequency vibration,found at a number of hydropower plants equipped with Francis turbines,and in some cases causing cracks in runner blades,is widely regarded as Karman vortex resonance by several studies.This study re-vealed a significant difference between the Karman vortex frequency and the natural frequency of the runner blade,and a new perspective was proposed based on the specific practice of reducing Karman vortex frequency vibration in Dachaoshan Power Station by decreasing trailing edge thickness,indicating that resonance was not the primary cause of strong vibration even when the vibration frequency was the Karman vortex frequency.The impact of dis-charge and cavitation coefficient on visible Karman vortices was examined in a model turbine Karman vortex obser-vation test.Visible Karman vortices were discovered easier to form in circumstances with larger discharge or lower cavitation coefficient.It was noted that Karman vortices became visible only when cavitation occurred in the vortex core.The analysis of effective vibration reduction operations revealed that Karman vortex resonance does exist at low flow conditions,but it was not noticed due to the small vibration amplitude;and the strong Karman vortex frequen-cy vibration at high flow conditions was caused by a massive impact force formed by the collapse of cavity bubbles rather than resonance.关键词
水轮机/卡门涡/共振/固有频率/振型/空化空腔Key words
turbine/Karman vortex/resonance/natural frequency/vibration mode/cavitation cavity分类
建筑与水利引用本文复制引用
孟龙,张驰也,徐洪泉,易艳林..混流式水轮机卡门涡致振机理探讨与分析[J].水利学报,2023,54(12):1464-1472,9.基金项目
中国水利水电科学研究院科研专项(HM0145B432016,HM0145B012021) （HM0145B432016,HM0145B012021）
