大型泵站新型钟形进水流道流动特性的研究

Study on hydraulic characteristics of new bell suction duct in large-scale pumping stations

钟形进水流道是我国大型泵站采用的两种最主要的进水流道形式之一。由于我国西南部地区年平均气压较低,在不增加基建投资及保障泵装置正常运行的要求下,提出了一种新的使通流面积变化率K趋近于常数的设计理论方法,对泵站的进水流道进行设计,并通过数值计算对新型钟形进水流道的流动特性进行了研究。结果表明:新型钟形进水流道的出口速度分布均匀度及速度加权平均角非常接近最理想值,完全满足叶轮室进口的流动要求;该设计方法已成功地用于云南某电厂4×600MW机组泵站进水流道的设计。研究结果为完善和简化传统钟形进水流道关键通流部件的设计提供了重要的理论依据。

Bell suction duct is one of the most important forms adopted in large-scale pumping stations.To enhance economic benefit and running stability in the lower atmospheric pressure areas such as Yunnan,a new design principle was put forward in this paper.The main idea was to keep the stream-wise decreasing rate of the flow cross-sectional area approximately a constant.Numerical analyses were carried out to study the hydraulic characteristics of the new bell suction duct.The results show that at the duct outlet the velocity-weighted average angle and the velocity distribution coefficient are nearly equal to the ideal values.The exit flow fully meets the requirements of the impeller.In addition,the investment of water-cooled thermal power plant can be saved if this new type bell suction duct is adopted.Thus this technology provides a new type of theory and method to large-sized pumping stations.