最高扬程与平均扬程相差较大的特低扬程泵站选型研究

设计规范要求"在平均扬程下水泵应在高效区工作"与"最高扬程时应保证稳定运行",对于最高扬程与平均扬程相差较大的特低扬程泵站,两者往往较难兼顾,该类泵站的选型难度很大。针对此类泵站,以新村枢纽为典型案例,为寻求高效率、易维护、低造价的泵型,进行了多方案比较,对电机调速、定速方案进行了分析,最终选择了竖井贯流泵及其定速方案。结果表明:根据工程特点,泵站选型时不必拘泥于平均扬程下必须在最高效区;运行中提前开泵、预降内河水位,适当提高实际扬程,延长水泵位于高效区运行时间,即能达到节能目的。泵装置水力性能优化及模型试验表明:泵装置的综合水力性能优良,水泵选型和流道设计合理;模型装置马鞍区峰点扬程大于2.8 m,满足泵站最高扬程稳定要求。溧阳城市防洪工程三大枢纽及新沟河延伸拓浚工程遥观南枢纽泵站均采用此泵型,工程于2013年起陆续投入使用,从运行效果看,机组运行状态良好。

Study on pump type selection for extra-low head pumping station with large difference between average and highest heads

It is required in the relevant design code that pump must operate in high efficiency area under the condition of average head and must guarantee stable operation under the condition of the highest head. However，both the requirements are often difficult to be simultaneously met by an extra-low head pumping station with large difference between the average head and the highest head，and then the pump type of this kind of pumping station is quite difficult to be selected. For this kind of pumping station，a comparison is made among several alternatives by taking Xincun Pumping Station Junction as the study case，so as to find out the pump type with the merits of high efficiency，easy maintenance and low cost; from which the speed-governing and speed-setting scheme for electric motor is analyzed，and then shaft tubular pump and its speed-setting scheme are selected at last. The result shows that in accordance with the characteristics of the project，it is not necessary to rigidly adhere to the requirement of that pump must operate in high efficiency area under the condition of average head for the type selection of the pumping station. The target of energy-saving can be got through starting pumping in advance，lowering the inland river water level beforehand，raising the actual head properly and prolonging the operation of the pump within the high efficiency area. It is indicated through the optimization of the hydraulic performance of the pumping unit and the relevant model experiment that the comprehensive hydraulic performance of the pumping unit is better，while the pump type selection and the flow-passage design are reasonable. The peak head in the saddle zone of the model device is larger than 2. 8 m，which can meet the stability requirement for the maximum head of the pumping station. This pump type is adopted for all the three pumping station junctions for Liyang Urban Flood Control Project and Yaoguannan Pumping Station Junction for Xingouhe River Dredging and Extending Project. Those projects are put into operation one after another from 2013，while the operation statuses of all the pumping units are better from the viewpoint of the operation effect.