水泵及泵装置效率换算方法  

Efficiency scaling method for pumps and their systems

作　　者：陆伟刚[1] 严登丰[1] 甄峰[1] 

机构地区：[1]扬州大学水利科学与工程学院,江苏扬州225009

出　　处：《排灌机械工程学报》2012年第6期677-682,689,共7页Journal of Drainage and Irrigation Machinery Engineering

基　　金：国家自然科学基金资助项目(50279045)

摘　　要：分析了传统效率换算公式的理论依据和有关标准推荐的效率换算方法,发现传统水泵效率换算式理论具有表达不完整、经验性重、通用性缺乏等问题;比较了由不同换算公式计算得到的最优工况点泵水力损失比,发现Medici式、Fromm式及两种Moody式原模型效率差值较大,其他各式较小,Ackeret式最小.研究提出了泵及泵装置'分部效率换算方法',从流体流动特性出发,介绍了3种不同流动区摩阻系数表达式,提出经数学处理的便于应用的简化公式;从泵内流动特性出发,分析和论证了摩阻系数的确定依据,研究了泵比例系数和摩阻系数对水泵效率换算的影响;推导提出了另一种效率常数计算方法;针对相同的原、模型水泵及泵装置实例,给出不同方法的效率换算结果,分析不同方法差异的原因及适用性.研究结果表明:相较于Ackeret式和Hutton式,泵比例系数对'分部效率换算法'的影响较小;采用'分部效率换算法'时,以任何流动区的公式计算摩阻系数其总效率并无明显差异.The theoretical bases of existing efficiency scaling formulas and several scaling methods re-commended in some industrial standards for pumps were analyzed.It was found that those formulas are incompletely mathematical expression,experience-dominated and less universal,etc.The hydraulic loss ratios and efficiency at the best efficiency point computed with different efficiency scaling formulas were compared,and it was identified that the efficiency of the prototypes scaled from the models by using Medici＇s and Fromm＇s and Moody＇s formulas shows quite difference compared with the measurements.The efficiency of the prototypes estimated by the rest formulas is less difference from the tests,in which Ackeret＇s formula gives a minimum error.A flow regime-depended efficiency scaling method for pump and its system was put forward,in which three formulas of skin friction factor for three flow regimes were introduced according to essentials of fluid mechanics,and then the corresponding mathematically simplified formulas were proposed for they to be applied conveniently.Based on the internal flow characteristics in pumps,the basis for determining the skin friction factor was analyzed and argued,and influences of the proportional constants of pump performance parameters and skin friction factor on the efficiency scaling were studied;eventually an additional method for estimating the efficiency coefficient was resulted.For the same prototype and model of pump and its system,the efficiencies scaled with those different methods were predicted;the reasons for difference in efficiency estimated and feasibility of the methods were analyzed.The results indicate that the proportional constants have less influence on the flow regime-depended efficiency scaling method compared with Ackeret＇s and Hutton＇s formulas.Thus,as the flow regime-depended efficiency scaling method is applied,the efficiency scaled with a skin friction factor in any flow regimes doesn＇t seem to show significant difference.

关 键 词：水泵效率 泵装置效率 效率常数 效率换算 

分 类 号：S277.9[农业科学—农业水土工程]