【作者】 滕书格；

【导师】 陈颂英；

【作者基本信息】 山东大学 ， 化工过程机械， 2008， 硕士

【摘要】 针对目前离心泵多目标优化问题,本文提出了泵的损失、汽蚀性能和稳定性三目标函数与超传递近似法相结合的多目标优化方法。其主要内容是考虑此三性能函数在泵的使用中重要程度的不同,通过超传递近似法对分目标函数予以评价,得到各目标函数的权值,从而得到离心泵几何参数的相对最优解。本文从数学模型的建立、程序优化、三维水力模型建立及网格划分和流场解析对比方面进行了研究。首先,根据各目标函数重要程度的不同,结合超传递近似法给出了各自的权值,通过线性加权的方法统一了目标函数,确定了合适的约束范围,从而建立了完整的数学模型。利用FORTRAN语言通过直接寻优的复合形法对数学模型进行了计算,最终得到了约束范围内的最佳变量组合。其次,利用三维制图软件pro/e对离心泵优化前后的叶轮和蜗壳分别进行了三维实体造型;利用CFD前处理软件GAMBIT对其进行了网格划分,并确定了模型的边界和流体的性质;利用FLUENT软件对整个流场进行仿真计算,湍流模型采用标准k-ε模型,压力速度耦合方式采用SIMPLE方法,得到了离心泵内部全流场数值解析数据。最后,应用后处理手段,得到了优化前后流场的速度矢量图、压力分布云图等,通过对流场情况的对比分析,我们发现优化后靠近叶轮流道入口处叶片背面的负压值明显小于优化前,且流道内部的轴线涡流基本消除,从而证明了优化方法的正确性及优化效果。更多还原

【Abstract】 In allusion to the multi-objective optimization of the centrifugal pump at present, a new multi-objective optimization method that combines the objectives that include the energy loss, the NPSH_r and the stability of the pump with the super-transitive approximate method is first proposed. The main contents are that the super-transitive approximate method is used to evaluate the important degree of the target functions and confirm the weight of the target functions and consequently the optimal parameters are obtained according to the important degree of the target functions, thus the paper will carry out the research in such aspects as up-building the mathematical model, writing optimization program, up-building three dimensional model, creating grid and numerical simulation of the flow field.First of all, according to important degree of the target functions, the weight of the target functions is confirmed. The target functions are unified by the linear weighted method and the right constraint conditions are confirmed. Then the full mathematical model is set up. The composite form method of the direct searching optimization is used to calculate the mathematical model by the FORTRAN language and finally the optimal parameters in the right constraint conditions are obtained.Secondly, the three dimensional entities of the impeller and volute chamber both before optimization and behind are plotted in the pro/engineer wildfire2.0.The grid of the flow field is created and the right boundary types and continuum types are presented in the GAMBIT. The flow field is simulated in the FLUENT and the standard k-εturbulence model and SIMPLE method were applied. The numerical results were obtained.Finally, the velocity vector and pressure fields both before optimization and behind were obtained.It was founded that the pressure value in the facing of a quilt of the vanes anear the entrance of the flow path behind optimization was less than before. The axial whirlpool was eliminated almost.Thus,the validity and the effect of the new multi-objective optimization method are proved.更多还原