论文部分内容阅读
采用分区动网格对叶片进行流固耦合分析时,动网格区选取不当,会影响计算效率及精度。考虑到叶片振动主要影响叶片周围的流场,取叶片附近区域为动网格区,并通过弹性体法实时更新其内部网格。采用RANS方程描述流场,并通过SIMPLE算法求解流场得到叶片表面静压。通过直接积分法求解叶片振动控制方程得到叶片响应。通过叶片振动与流场之间的迭代求解实现流固耦合计算。采用对数衰减率评估叶片振动的稳定性,对数衰减率为0时的压比即为颤振临界压比。计算了轴流压气机叶片的颤振边界,并研究了动网格区对计算效率及精度的影响。结果表明,对于叶高为0.17m左右的轴流压气机叶片来说,取动网格区外边界到叶片的距离与叶片最大位移的比值约为2时,能够在保持计算精度的前提下,最大限度地提高计算效率,计算时间比全域动网格减少了13.4%,颤振临界压比的计算值相对全域动网格的误差为0.49%。
When the moving grid is used to analyze the fluid-structure interaction of moving blades, the moving grid area is improperly selected, which will affect the calculation efficiency and precision. Considering that the vibration of the blade mainly affects the flow field around the blade, the area near the blade is a moving grid area, and the internal grid of the blade is updated in real time by the elastic method. The RANS equation is used to describe the flow field and the blade surface static pressure is obtained by SIMPLE algorithm. The blade response is obtained by solving the blade vibration control equation by the direct integral method. The fluid-solid coupling calculation is realized by the iterative solution of blade vibration and flow field. The logarithmic decay rate was used to evaluate the stability of blade vibration. The pressure ratio at logarithmic decay rate is the critical pressure ratio of flutter. The flutter boundary of the axial compressor blades is calculated and the influence of moving grid area on calculation efficiency and accuracy is studied. The results show that for axial-flow compressor blades with a blade height of about 0.17 m, the ratio of the distance from the outer boundary of the grid to the blade and the maximum displacement of the blade is about 2, while maintaining the accuracy of the calculation, The computational efficiency is reduced by 13.4% compared with the global moving grid and the error of the calculated value of the flutter critical pressure ratio is 0.49% relative to the global moving grid.