叶型最大挠度点位置对轴流泵流动激励力及其流动噪声的影响分析

叶型最大挠度点位置的移动对轴流泵叶片吸力面的附面层流动有较大影响,从而影响轴流泵的流动效率。利用计算流体力学方法对叶轮叶片具有不同叶型最大挠度点位置N_c的轴流泵模型内部定常和非定常流场进行数值模拟,分析轴流泵内非定常压强分布随N_c变化的规律。研究结果表明:随着N_c向叶片尾部移动,轴流泵扬程和效率均提高;N_c从0.3增大至0.4时,扬程提高了0.94 m,约20.3%,效率提高了2.7%;N_c从0.4增大至0.6时,扬程提高了0.25 m,约4.5%,效率提高了0.3%.从叶高静压分布和泵内流动激励力均可以看出,N_c为0.4、0.5和0.6时的流场相对于N_c为0.3时更有利于提高流动效率。轴流泵的声场结果表明,N_c=0.6时声压级最低,且振速最小。

Impact of NACA airfoil's maximum deflection position of axial flow excitation force flow analysis

Mobile NACA airfoil maximum deflection point position will change the position of speed separation point in the suction side of the blade axial flow, thus changing the flow field and affects efficiency. Computational fluid dynamics method is used to simulate the flow field calculation of axial flow pump, simulate axial flow pump internal flow field and analysis the shell wall pressure fluctuation. The results showed that, as the maximum deflection position N_c move to the point of the tail vane, axial head and efficiency are both improved. While N_c changed from 0.3 to 0.4, the efficiency increased by 2.7% and head raised 0.94 m, about 20.3%. While N_c changed from 0.4 to 0.6, the efficiency increased by 0.3% and head raised 0.25 m, about 4.5%. From the distribution of blade static pressure and pump fluid exciting force, we can see that compared with N_c=0.3 of the flow field, N_c=0.4, 0.5 and 0.6 is more conducive to improve the efficiency of the flow. The sound field results indicate that N_c=0.6 has minimum SPL and minimum vibration velocity.