一种多目标泵的设计与分析

介绍了某项目用泵的2个需求工况点,应用欧拉扬程公式计算单叶轮设计时的叶轮外径,并计算圆盘摩擦损失预估泵效率,初步分析表明单叶轮设计不仅效率极低,而且也无法满足2个设计目标。针对比开发了一种双叶轮双出口组合的新型结构型式,介绍了其工作原理。其中主要过流部件采用模型换算法,应用面积比法计算正导叶外接的首级叶轮蜗壳的第Ⅷ断面面积。根据模型试验数据换算得到该多目标泵的外特性曲线并用现代CFD技术进行了数值仿真。发现扬程—流量曲线的模型试验数据与仿真结果曲线一致,满足2个工况点的目标需求。与模型换算数据相比,数值仿真得到的数据最高效率点向大流量方向偏移,这是由于第一级蜗壳是以正导叶为基础采用面积比法设计、过流断面大导致的。

Analysis and Design for a Multi-objective Pump

A certain pump need to be used at two conditions.Euler equation was used to evaluate the impeller diameter for a single impeller design case.Primary analysis showed that one impeller design had too low efficiency and can not reach the two required operating conditions.A new multi-objective pump with two cascade impellers and two discharge flanges was developed and its running principal was introduced.The hydraulic parts were model scaled except that the volute downstream the radial diffuser was designed by area-ratio method.The overall characteristics of the pump were numerically simulated and scaled.The head-flow curve evaluated was agree well with that of model scaled and matched the required conditions.The efficiency-flow curve evaluated has deficiency than that of model scaled and the best efficiency point move to large flow rate area.The former is because of the simple structure of the models causing high efficiency while the latter due to the large section area design of the first stage volute.