常规立方晶格点阵轮的设计与静力学分析

为实现压气机叶轮在刚度和强度具有可调性的同时降低叶轮质量,基于常规立方晶格结构设计出一种新型轻量化压气机叶轮。通过3种模型悬臂梁比较计算,证明渐进均匀化(asymptotic homogenization,AH)方法在大规模点阵计算问题上具有较好的计算精度。在此基础上,采用AH方法对不同单胞填充率的点阵轮在仅考虑80 000 r/min的惯性荷载时的静力学性能进行了数值计算。研究结果表明,对于所研究路径,点阵轮的变形和应力介于无填充轮和实心轮之间,大叶片外缘的周向变形最大与最小变形差值(极差)在所有研究工况下均小于无填充轮和实心轮。对于填充率为0.4的情况,其周向变形极差值比实心轮约低23.25%,比无填充轮约低55.46%,其质量相对于实心轮可降低17.08%。这意味着点阵轮相对于传统压气机叶轮除了能较大降低叶轮质量,还将具有更好的周向抗畸变能力和更高的工作效率。同时,点阵轮相对于无填充轮和实心轮叶片边缘具有更小的轴向应力,因此可为设计更高转速的压气机叶轮提供强度保证,同时也为叶轮结构的轻量化设计提供了一种新的设计思路。

Design and static analysis of conventional cubic lattice impeller

In order to realize the adjustable stiffness and strength of compressor impeller and reduce the mass of the impeller, a new lightweight compressor impeller was designed based on the conventional cubic lattice structure. Based on the comparative calculation of three models of cantilever beam, it has been proved that the asymptotic homogenization (AH) method has good accuracy in large-scale lattice calculation. On this basis, the AH method was used to calculate the static performance of lattice impeller with different cell filling rates under the inertial load of 80 000 r/min. Results show that for the studied path, the deformation and stress of the lattice impeller were between those of the unfilled impeller and the solid impeller, and the difference (range) between the maximum and minimum circumferential deformation of the outer edge of the large blade was smaller than those of the unfilled impeller and the solid impeller. When the filling rate was 0.4, the circumferential deformation range of the lattice impeller was 23.25% lower than that of the solid impeller, 55.46% lower than that of the unfilled impeller, and the mass of the lattice impeller could be reduced by 17.08% compared with solid impeller. It indicates that in comparison with the traditional compressor impeller, lattice impeller can not only greatly reduce the impeller mass, but also has better circumferential distortion resistance and higher work efficiency. Meanwhile, the blade edge of lattice impeller has smaller axial stress than those of unfilled impeller and solid impeller, so it can provide strength guarantee for the design of compressor impellers with higher speed. The design of this paper also provides a new design idea for the lightweight design of impeller structures.