摘要
为了探明滴灌加压泵站调速运行条件,分析了滴灌泵站运行特点,并在叶片泵基本方程基础上分析了滴灌泵站装置运行工况与离心泵调速运行工况之间的关系,以及影响调速工况等效性的因素。结果表明,虽然在理论上滴灌泵站调速运行中离心泵运行工况可以无条件等效,但是,实践中滴灌系统过滤装置水头损失升高,使系统装置特性曲线斜率增大,并且还随着水泵调速幅度的增加而增大,不仅使得水泵调速前、后工况效率不相等,还将导致滴灌系统不能正常工作。所以滴灌泵站的调速范围应小于允许的单泵调速运行范围。另外,水泵降速超过一定范围后造成叶轮内速度三角形夹角α2(叶轮出口处叶片的牵连速度与流体绝对速度之间的夹角)增大,叶轮水力条件不再相似,水泵调速前、后的运行工况的效率不再相等。本研究对完善滴灌泵站管理理论有帮助。
The operation characteristics of pumping stations are analyzed for drip irrigation systems （DIS） in this paper to learn the operation conditions of the pumping station under regulated rotational speed （RS）, as well as factors influencing the iso-efficiency op- eration of centrifugal pumps. The relation between DIS operation points and the centrifugal pump operation points are analyzed based on the basic equation of impeller pumps. Results indicate that the pumping station can iso-efficiently run with any RS theoretically for drip irrigation systems. But the slope of characteristic curve for DIS is increased by the raised head-loss of filtration system in the DIS and is further increased by regulated RS of centrifugal pumps. Consequently, the regulation of RS not only renders pump operation with various efficiencies, but also the DIS running abnormally. It is believed that the RS regulating rang of the pump for DIS should be narrowed. In addition, the pump would run with unstable efficiency when its RS was once regulated beyond allowable range, be- cause the excessive regulation of RS results in the angle a2, which the velocity of blade tip to the fluid absolute velocity at impeller outlet for the fluid velocity triangle in impeller, is increases and the hydraulic conditions in impeller are non-analogous. These efforts are helpful in the interpretation and development of management policies for the pumping stations of drip irrigation systems.
出处
《中国农村水利水电》
北大核心
2013年第5期137-140,144,共5页
China Rural Water and Hydropower
基金
国家节水灌溉工程技术研究中心(新疆)联合基金项目(Z200901)
石河子大学"263"计划项目(SJ08014)
关键词
滴灌泵站
变速调节
效率
离心泵
叶轮速度三角形
pumping station for drip irrigation system
speed regulation
efficiency
centrifugal pump
velocity triangle of impeller
