基于NSGA-II的S翼型及双向轴流泵多目标优化  

Multi-objective optimization of S-shaped hydrofoil and bidirectional axial-flow pumps based on NSGA-II

作　　者：孙壮壮 朱亚东[1,2] 陈加琦 王梦成 汤方平 吕宁[1] 陈松山 SUN Zhuangzhuang;ZHU Yadong;CHEN Jiaqi;WANG Mengcheng;TANG Fangping;LYU Ning;CHEN Songshan(School of Mechanical Engineering,Yangzhou Polytechnic College,Yangzhou 225100,China;College of Electrical and Energy Power Engineering,Yangzhou University,Yangzhou 225100,China;College of Hydraulic Science and Engineering,Yangzhou University,Yangzhou 225100,China)

机构地区：[1]扬州市职业大学机械工程学院,扬州225100 [2]扬州大学电气与能源动力工程学院,扬州225100 [3]扬州大学水利科学与工程学院,扬州225100

出　　处：《农业工程学报》2024年第24期39-48,共10页Transactions of the Chinese Society of Agricultural Engineering

基　　金：江苏省自然科学基金(SBK2023042972);中国博士后科学基金(2023M741499);江苏省高效节能大型轴流泵站工程研究中心开放课题(ECHEAP022);扬州市自然科学基金(YZ2024193);扬州市绿杨金凤计划(2023);扬州市职业大学校级科研项目(2023XJ02)。

摘　　要：为了提高双向轴流泵的水力效率,该研究以某比转速(正向运行) 1200 左右的高比转速双向泵为对象,进一步探索双向泵的优化设计方法。在验证数值计算的准确性的基础上,基于NSGA-II(第二代非劣分类遗传算法,non-dominated sorting genetic algorithm-II),选取叶轮跨中附近的可逆翼型(S翼型),优化不同攻角(+2°、+4°和+6°)下的翼型性能。以翼型加权空化性能最优和升阻比最大为优化目标,在保证双向泵扬程不变的前提下,以原翼型设计攻角下升力系数基本不变为约束,保持S翼型最大厚度和最大厚度位置不变,对控制翼型中弧线形状及厚度弦向分布的12个参数进行优化求解。从Pareto解集中选取升阻比性能和空化性能较优的S翼型作为双向泵叶轮的优选模型,并对比优化前后的叶轮性能。研究结果表明:在得到的115组Pareto解集中,S翼型升阻比指标最大提升27.3%,空化指标最大提升27.7%。在一定范围内减小翼型的最大拱度有利于提升升阻比,而增大翼型拱度则有利于提升空化性能。优化后双向泵扬程基本不变而效率提升明显,在0.8、1.0和1.2倍正、反向设计流量下,正向效率分别提升0.6、0.5和2.2个百分点,反向效率分别提升1.1、0.2和0.4个百分点,叶轮内部流场得到明显改善。正、反向设计流量工况下,泵的临界空化数变化较小(分别增大0.013和0.006),而初生空化数显著降低(均降低0.5左右)。研究结果可为可逆式旋转机械的优化设计提供参考。Bidirectional axial-flow pumps can be used to fully meet the urban demand for drought response and two-way water transfer in recent years.This study aims to optimize the high-specific-speed bidirectional pumps with a specific speed(forward operation)of around 1200,in order to improve the hydraulic efficiency.The numerical calculations were also validated using NSGA-II(Non-dominated sorting genetic-II).A reversible hydrofoil(S-shaped hydrofoil)near the middle span of the impeller was selected and then optimized for various attack angles(+2°,+4°,and+6°).A series of optimizations were implemented to maximize the weighted cavitation and lift-to-drag ratio of the hydrofoil while maintaining the lift coefficient at the original hydrofoil angle under the constraint of an unchanged bidirectional pump head.The maximum thickness and position of the S-shaped hydrofoil remained constant during this time.The camber line shape was described using a fourth-order Bezier curve,while the distribution of thickness was represented by combining the arcs and fourth-order Bezier curves.12 parameters were optimized to consider the camber line and thickness distribution.A total of 1680 iterations were performed using NSGA-II,resulting in a Pareto solution set for cavitation performance and lift-to-drag ratio.The emergence of the Pareto frontier indicated a trade-off relationship between the lift-drag and cavitation performance of the hydrofoil.Among the 115 Pareto solutions,the maximum lift-to-drag ratio and cavitation performance were approximately 27.3%and 27.7%,respectively.The optimal Sc1 for lift-to-drag ratio,the optimal Sc3 for cavitation performance,and the compromise solution Sc2 were selected to further compare their shape and pressure coefficient distribution.The lift coefficients of three hydrofoil schemes before and after optimization were basically consistent at different attack angles.The minimum pressure coefficient on the hydrofoil surface gradually increased from Sc1 to Sc3.Compared with the original scheme,the maxim

关 键 词：水力机械 轴流泵 可逆翼型 优化设计 

分 类 号：TH313[机械工程—机械制造及自动化]