355 多目的遺伝的アルゴリズムによるフランシス水車吸出し管の最適化(G05-7 流体機械(2),G05 流体工学)  [in Japanese] 355 Design Optimization of a Francis Turbine Draft Tube by Using Multi-Objective Genetic Algorithm  [in Japanese]

Usually, The draft tube of a Francis turbine is laid underground, therefore, amount of excavation is changed by draft tube depth. Though a deep draft tube depth produces good turbine performance, amount of excavation increases and the cost also increases. On the other hand, it is ideal that a draft tube depth is shallow and it has good turbine performance. In this paper, it introduces the profile optimization of a Francis turbine draft tube by CFD that is combined with Multi-Objective Genetic Algorithm (MOGA). The objective functions in MOGA are turbine performances and a draft tube depth, and the number of the draft tube design parameters optimized by MOGA is about 80. From the optimization, the new profile which is shallower depth and has higher performance than original can be obtained.