Author(s): Dandan Yang, Zhe Wang, Xianwu Luo, Jiajian Zhou, Hongyuan Xu
Linked Author(s): Dandan Yang
Keywords: Axial pump, internal flow, modified Partially-Averaged Navier-Stokes (MPANS) model, design optimization, hydraulic performance
Abstract: The present paper aims to simulate the three-dimensional turbulent flows in an axial pump. The pump has the flow discharge of 0. 562 m3/s, and the head rise of 11. 24 m at the rotational speed of 1400 r/min. The numerical simulation was conducted based on the Reynolds average Navier-Stokes equations and Shear Stress Transport (SST) model to depict the flow evolutions in the pump. The predicted hydraulic performance on the pump agreed fairly well with experiment data. It is noted that the shaft power is not sensitive to the axial spacing for all operation conditions, and the hydraulic efficiency may improve a little due to the better flow pattern at stator zone for the smaller axial spacing between the rotor and stator. The head rise and shaft power increased with decreasing the tip gap and the efficiency reached the maximum value at the tip gap 0. 3 mm. The maximum vorticity occurred near the pressure side of the rotor blade decreased with the increase of the tip gap. Near the hub, the tip gap effect on the pressure coefficient distribution is not remarkable with increasing the tip gap from 0. 5 mm to 0. 7 mm. Further, the effect of numerical method on pump internal flow was also investigated by two turbulence models, i. e. SST model and modified Partially-Averaged Navier-Stokes (MPANS) model. Though both turbulence models over predicted the velocity wake deficit near the hub, MPANS model achieved a closer axial velocity distribution to the experimental result and can capture the vortex structure with better accuracy compared with SST model. This study would be helpful for the design optimization for the axial pump with low specific speed ranging from 630-1260 m3min-1?min-1?m in the future
Year: 2017