某型燃气轮机枞树形榫接结构多齿形参数优化分析

Structural Analysis and Optimization of Gas Turbine Fir-Tree Attachment with Various Tooth Profile Parameters

在某型燃气轮机改型设计中发现,涡轮采用的3齿枞树形榫接结构应力集中严重,为避免榫齿出现裂纹、榫头断裂等故障,并降低峰值应力,延长使用寿命,对其形状进行优化设计。分析发现,相同的齿形参数无法获得满意的优化结果,因此,对每对榫齿采用不同的齿形参数进行2维参数化建模。通过试验设计方法,选取对最大当量应力影响较大的参数作为设计变量并进行优化。在满足约束的条件下,获得优化设计结果。结果表明:优化使最大当量应力降低19.93%,各齿应力分布更加均匀。该设计方法确实能提升榫接结构的优化潜力,对其设计与优化具有一定参考价值。

In the redesign of a gas turbine, stress concentration was seriously found in the three teeth fir-tree attachment, which may cause initiate crack. In order to decrease stress level and prolong service life, shape optimization was applied. Based on feature-based modelling method, 2-D parametric model was established. When analyzing the original design, the same tooth profile parameters in design lacked improvement potential, so each tooth was modelled with various tooth profile parameters. The Optimized Latin Hypercube method was adopted to extract design variables from a large number of geometry parameters and the Multi-Island Genetic Algorithm was used to explore optimized design under constraints. The result indicates that the maximum Von Mises stress decreases by 19.93% and stress distribution becomes more uniform, various tooth profile parameters in design improves the optimization potential and provides a kind of reference to the design of fir-tree attachment.