Study on the influence of blade outlet angle on unsteady flow and structural dynamic characteristics for chemical process pump

Asian Working Group- IAHR's Symposium on Hydraulic Machinery and Systems

Zhang, J.F.^1 ; Zhang, X.^1 ; Xie, L.H.^1

National Research Centre of Pumps, 301 Xuefu Road, Zhenjiang, Jiangsu

212013, China^1

关键词: Bidirectional coupling;    Dynamic characteristics;    Fluid-solid coupling;    High specific speed;    Inherent frequencies;    Numerical calculation;    Structural behaviour;    Third-harmonic frequencies;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/163/1/012047/pdf
DOI  :  10.1088/1755-1315/163/1/012047

来源: IOP

【 摘 要 】

In order to reveal the influence of the blade outlet angle on the structural dynamic characteristics of chemical process pump, a chemical process centrifugal pump with high specific speed was selected to be researched, and 4 impellers with different blade outlet angle were redesigned based on the prototype pump, which ensuring that the other geometrical parameters unchanged. The blade outlet angle designed are 27°, 37°, and 47°, referring to the original impeller whose blade outlet angle was 22°. Then, the numerical calculation was applied for each scheme under designed condition based on the bidirectional coupling fluid- structure interaction (FSI) simulations. Through simulation, the head after the fluid-solid coupling was lower than before, but the error was reduced. Comparing the distribution of equivalent stress at intersection boundary, it shows that the places from 0.6 times to 0.8 times at the outlet of the intersection boundary of stress side and shroud were greatly affected by blade outlet angle, and the places from 0.8 times at the outlet to the outlet at the intersection boundary of stress side and shroud were also greatly affected by blade outlet angle. In addition, the equivalent stress increases with the increasing of blade outlet angle, and the place near the outlet all tend to have the phenomenon of stress concentration. Moreover, the total deformation shows, the deformation could be reduced through reducing the blade outlet angle. Also, the structural behaviour of the impeller indicates the first-order inherent frequency was much higher than the blade frequency, and it avoided the second harmonic frequency and the third harmonic frequency. The inherent frequency could be improved when the blade outlet angle was relatively bigger, but if it was too big, it would cause swing and twist, and if it was lesser, the total deformation could be uniform.