基于最大正应力的水轮机顶盖轻量化优化设计（英文）
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摘要
顶盖是水轮机中起承载和过流双重作用的重要部件.以混流式水轮机顶盖为研究对象,建立有限元模型,对其强度、刚度和动力特性进行仿真分析.以最大正应力和刚度两种设计指标作为约束条件,对顶盖进行以质量最小为目标的优化设计,提出轻量化目标优化方法.根据仿真分析结果,确定顶盖结构改进方案.优化后顶盖的最大应力及最大位移均有所降低,各阶固有频率相应提高,动力特性得到明显改善.轻量化优化设计使水轮机顶盖结构的质量减轻250 kg,减重率达13. 2%,实现了轻量化目的.
The head cover is an important component serving for the dual functions of load bearing and through flow in water turbine. Taking head cover of the Francis turbine as the research object,the strength,the stiffness and the dynamic characteristics of head cover have been simulated and analyzed by means of establishing a finite element model. With the two design indexes of maximum normal stress and stiffness as the constraint conditions,an optimized design aimed at minimum mass was explored and a lightweight optimization method was proposed.According to the results of simulation analysis,the structural improvement of head cover was determined.Through optimization,the maximum normal stress and maximum displacement of head cover are both reduced,with the natural frequency of each order accordingly increased and the dynamic characteristics significantly improved. The lightweight optimization design reduced the weight of head cover in water turbine by 250 kg and the weight-loss ratio reaches 13. 2%,thus achieving the purpose of lightweight.
The head cover is an important component serving for the dual functions of load bearing and through flow in water turbine. Taking head cover of the Francis turbine as the research object,the strength,the stiffness and the dynamic characteristics of head cover have been simulated and analyzed by means of establishing a finite element model. With the two design indexes of maximum normal stress and stiffness as the constraint conditions,an optimized design aimed at minimum mass was explored and a lightweight optimization method was proposed.According to the results of simulation analysis,the structural improvement of head cover was determined.Through optimization,the maximum normal stress and maximum displacement of head cover are both reduced,with the natural frequency of each order accordingly increased and the dynamic characteristics significantly improved. The lightweight optimization design reduced the weight of head cover in water turbine by 250 kg and the weight-loss ratio reaches 13. 2%,thus achieving the purpose of lightweight.
引文
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[6]Shao Guohui,Wang Qianyun.Optimization design of the high specific speed francis turbine of zangmu power station[J].Water Sciences and Engineering Technology,2013(3):51-56.
[7]Qi Xueyi,Li Chenchen,Zhang Xinjie,et al.The reliability design and calculation of hydraulic turbine head cover[J].Large Electric Machine and Hydraulic Turbine.2008(2):40-43.
[8]Feng Fuzhou,Chu Fulei.Dynamic analysis of a hydraulic turbine unit[J].Mechanics of Structures and Machines,2001,29(4),505-531.
[9]Li Zhaojun,Yang Xunjuan,Cai Ganwei,et al.Frequency reliability analysis of the runner blade of Francis turbine[J].Machinery Design&Manufacture,2010(6):128-129.
[10]Li Zhaojun,Liu Yang,Long Hui,et al.Nonlinear vibration reliability of hydraulic turbine-generator units with multiple failure modes[J].Journal of Mechanical Engineering,2013,49(16):170-176.
[11]Marler R T,Arora J S.Survey of multi-objective optimization methods for engineering[J].Structural and Multidisciplinary Optimization,2004,26(6):369-395.
[12]Yamasaki S,Nishiwakis,Yamada T,et al.A structural optimization method based on the level set method using a new geometry-based re-initialization scheme[J].International Journal for Numerical Methods in Engineering,2010,83(12):1580-1624.
[13]Christensen P W,Klarbring A.An introduction to structural optimization[M].Dordrecht,Holland:Springer Science,2009.
[2]Wang Zhizhong,Liu Linzhang.Development and prospect of hydraulic turbine[J].Journal of Water Resources and Architectural Engineering,2006,4(4):36-41.
[3]Gustavsson R K,AidanpaaJ O.Evaluation of impact dynamics and contact forces in a hydropower rotor due to variations in damping and lateral fluid forces[J].International Journal of Mechanical Sciences,2009,51(9/10):653-661.
[4]Wu J C,Shimmei K,TANI K,et al.CFD-based design optimization for hydro turbines[J].Journal of Fluids Engineering,Transactions of the ASME,2007,129(2):159-168.
[5]Wang Bo,Liu Xianli,Liu Jingshi,et al.Structural optimization and manufacturing for region of high stress of pelton turbine[J].Journal of Mechanical Engineering,2015,51(21):148-155.
[6]Shao Guohui,Wang Qianyun.Optimization design of the high specific speed francis turbine of zangmu power station[J].Water Sciences and Engineering Technology,2013(3):51-56.
[7]Qi Xueyi,Li Chenchen,Zhang Xinjie,et al.The reliability design and calculation of hydraulic turbine head cover[J].Large Electric Machine and Hydraulic Turbine.2008(2):40-43.
[8]Feng Fuzhou,Chu Fulei.Dynamic analysis of a hydraulic turbine unit[J].Mechanics of Structures and Machines,2001,29(4),505-531.
[9]Li Zhaojun,Yang Xunjuan,Cai Ganwei,et al.Frequency reliability analysis of the runner blade of Francis turbine[J].Machinery Design&Manufacture,2010(6):128-129.
[10]Li Zhaojun,Liu Yang,Long Hui,et al.Nonlinear vibration reliability of hydraulic turbine-generator units with multiple failure modes[J].Journal of Mechanical Engineering,2013,49(16):170-176.
[11]Marler R T,Arora J S.Survey of multi-objective optimization methods for engineering[J].Structural and Multidisciplinary Optimization,2004,26(6):369-395.
[12]Yamasaki S,Nishiwakis,Yamada T,et al.A structural optimization method based on the level set method using a new geometry-based re-initialization scheme[J].International Journal for Numerical Methods in Engineering,2010,83(12):1580-1624.
[13]Christensen P W,Klarbring A.An introduction to structural optimization[M].Dordrecht,Holland:Springer Science,2009.