基于模糊理论的三维无叶扩压器多目标优化

The Multi-Criteria Optimization of 3D Vaneless Diffuser Based on Fuzzy Theory

建立了一种基于模糊理论的无叶扩压器优化模型,并采用人机交互的修改单纯形法(IMS)进行求解,模型同时考虑了扩压器的静压升和全压损失.采用计算流体动力学(CFD)方法求解RANS方程得到扩压器的流场分布,从而获得单步优化目标函数值.在采用IMS方法获得新的盖侧曲线后,进行网格重绘,以防止盖侧出现网格线交叉和避免负网格的生成.盖侧曲线采用工程上常用的B样条拟合.优化结果和文献中的结果吻合较好.

An optimization model based on fuzzy theory was set up and the corresponding IMS （interactive modified simplex） method was developed to solve it. Both static pressure recovery and total pressure loss are considered in the model. CFD （computational fluid dynamics） method was applied to solve the Reynolds-Averaged Navier-Stokes （RANS） equation and get flow field distribution in order to get the value of object function. After receiving the new shroud curve, grid movement and redrawing technology were adopted to avoid grid-line crossing and negative cells. The shroud curve is fitted with B-spline. The optimized results agree well with the available results in reference.