排灌机械工程学报2012，Vol.30Issue(1)：25-29,5.DOI:10.3969/j.issn.1674-8530.2012.01.006
涡轮出口旋流对扩大管压力回复性能的影响
Effect of runner outlet swirling flow on diffuser pressure recovery
摘要
Abstract
In order to study the effect of swirling kinetic energy at runner outlet on the pressure recovery performance of a straight diffuser with a larger cone angle, the hydrodynamic mechanism and rules behind the effect were investigated with computational fluid dynamics. A bulb turbine with adjustable guide vanes and runner vanes was employed as the model. The 3D flow through the whole channel of the turbine, from the inlet to the case including bulb and stay vanes, guide vanes, runner vanes to the outlet of draft tube (diffuser) was computed. Through calculating the pressure recovery coefficient Cp and the specific hydraulic deficiency 5D of the draft tube in a wide operating range, a hydrodynamic relationship between the optimum swirling kinetic energy and the maximum pressure recovery in the straight diffuser was established, subsequently, the hydraulic performance of the draft tube was predicted. A new parameter, named kinetic energy distortion rate Iek at the outlet of diffuser was defined,and the pattern of kinetic energy in diffuser was compared under various inflow swirls. The result revealed that there is a clear correlation between lek and Cp,that is,when the distortion rate Iek is minimum,the recovery coefficient Cp is the peak and the deficiency 8D is minimum. Thus, the new parameter Iek can be used as an index for evaluating the quality of swirling flow through a straight draft tube in the bulb turbine with adjustable guide vanes and runner vanes.关键词
涡轮/贯流式水轮机/扩大管/压力回复/旋回流动/协联工况/动能歪曲度Key words
runner/bulb turbine/diffuser/pressure recovery/swirling flow/on-cam performance/kinetic energy distortion rate分类
农业科技引用本文复制引用
韩凤琴,王幼青,高海鹏,久保田乔..涡轮出口旋流对扩大管压力回复性能的影响[J].排灌机械工程学报,2012,30(1):25-29,5.基金项目
国家自然科学基金资助项目(50879026) （50879026）
