The three-dimensional unsteady turbulent flow in axial-flow pumps was simulated based on Navier-Stoke solver embedded with k - ε RNG turbulence model and SIMPLEC algorithm. Numerical results show that the unsteady pr...The three-dimensional unsteady turbulent flow in axial-flow pumps was simulated based on Navier-Stoke solver embedded with k - ε RNG turbulence model and SIMPLEC algorithm. Numerical results show that the unsteady prediction results are more accurate than the steady results, and the maximal error of unsteady prediction is only 4.54%. The time-domain spectrums show that the static pressure fluctuation curves at the inlet and outlet of the rotor and the outlet of the stator are periodic, and all have four peaks and four valleys. The pressure fluctuation amplitude increases from the hub to the tip at the inlet and outlet of the rotor, but decreases at the outlet of the stator. The pressure fluctuation amplitude is the greatest at the inlet of the rotor, and the average amplitude decreases sharply from the inlet to the outlet. The frequency spectrums obtained by Fast Fourier Transform （FFT） show that the dominant frequency is approximately equal to the blade passing frequency. The static pressure on the pressure side of hydrofoil on different stream surfaces remains almost consistent, and increases gradually from the blade inlet to the exit on the suction side at different time steps. The axial velocity distribution is periodic and is affected by the stator blade number at the rotor exit. The experimental results show that the flow is almost axial and the pre-rotation is very small at the rotor inlet under the conditions of 0.8 QN -1.2 QN Due to the clearance leakage, the pressure, circulation and meridional velocity at the rotor outlet all decrease near the hub leakage and tip clearance regions.展开更多
The experimental investigation of axial-flow pump has been rapidly developed to meet the needs of South-to-North Water Diversion Project of China. Owing to the boundary conditions of hub, blade tip clearance, much of ...The experimental investigation of axial-flow pump has been rapidly developed to meet the needs of South-to-North Water Diversion Project of China. Owing to the boundary conditions of hub, blade tip clearance, much of the physical phenomena and laws involved in this complex flow field can＇t be fully determined. The flow characteristics of the high efficiency axial-flow pump have been simulated by RNG k-e turbulence model and SIMPLEC arithmetic based on FLUENT software. Numerical results indicate that the data from the prediction show agreement with the experimental results, static pressure on pressure side of blades increases slightly at circumferential direction with radius increasing, and keep almost constant at the same radial while increasing gradually from inlet to exit on the suction side along flow direction at design conditions. The static pressure, total pressure and velocity at inlet, impeller outlet and vane outlet were measured by a five-hole probe, and a contrastive experiment was done to investigate the influence of hub leakage. The experimental results show that inlet flow is almost axial and the prerotation is very small at various conditions. The meridional velocity and circulation distribution are almost identical at impeller outlet at design conditions due to steady flow and high efficiency. The residual circulation exits at downstream of the guide vane, and the circumferential velocity component increases linearly from hub to tip at small flow rate conditions. Hub leakage in adjustable blades results in the decrease of the meridional velocity and circulation at blade exit near hub. The results of numerical simulation and experiments supply important flow structure information for the high-efficiency axial-flow pump.展开更多
基金Project supported by the National High Technology Research and Development Program of China (863 Program,Grant No.2007AA05Z207)the Graduate Student Innovation Foundation of Jiangsu Province (Grant No.CX08B_064Z)the National Science and Technology Support Program (Grant No.2008BAF34B15)
文摘The three-dimensional unsteady turbulent flow in axial-flow pumps was simulated based on Navier-Stoke solver embedded with k - ε RNG turbulence model and SIMPLEC algorithm. Numerical results show that the unsteady prediction results are more accurate than the steady results, and the maximal error of unsteady prediction is only 4.54%. The time-domain spectrums show that the static pressure fluctuation curves at the inlet and outlet of the rotor and the outlet of the stator are periodic, and all have four peaks and four valleys. The pressure fluctuation amplitude increases from the hub to the tip at the inlet and outlet of the rotor, but decreases at the outlet of the stator. The pressure fluctuation amplitude is the greatest at the inlet of the rotor, and the average amplitude decreases sharply from the inlet to the outlet. The frequency spectrums obtained by Fast Fourier Transform （FFT） show that the dominant frequency is approximately equal to the blade passing frequency. The static pressure on the pressure side of hydrofoil on different stream surfaces remains almost consistent, and increases gradually from the blade inlet to the exit on the suction side at different time steps. The axial velocity distribution is periodic and is affected by the stator blade number at the rotor exit. The experimental results show that the flow is almost axial and the pre-rotation is very small at the rotor inlet under the conditions of 0.8 QN -1.2 QN Due to the clearance leakage, the pressure, circulation and meridional velocity at the rotor outlet all decrease near the hub leakage and tip clearance regions.
基金supported by National Hi-tech Research and Development Program of China (863 Program, Grant No. 2007AA05Z207)National Science and Technology Support Scheme of China (Grant No. 2008BAF34B10)Jiangsu Provincial Graduate Student Innovation Foundation of China (Grant No. CX08B_064Z)
文摘The experimental investigation of axial-flow pump has been rapidly developed to meet the needs of South-to-North Water Diversion Project of China. Owing to the boundary conditions of hub, blade tip clearance, much of the physical phenomena and laws involved in this complex flow field can＇t be fully determined. The flow characteristics of the high efficiency axial-flow pump have been simulated by RNG k-e turbulence model and SIMPLEC arithmetic based on FLUENT software. Numerical results indicate that the data from the prediction show agreement with the experimental results, static pressure on pressure side of blades increases slightly at circumferential direction with radius increasing, and keep almost constant at the same radial while increasing gradually from inlet to exit on the suction side along flow direction at design conditions. The static pressure, total pressure and velocity at inlet, impeller outlet and vane outlet were measured by a five-hole probe, and a contrastive experiment was done to investigate the influence of hub leakage. The experimental results show that inlet flow is almost axial and the prerotation is very small at various conditions. The meridional velocity and circulation distribution are almost identical at impeller outlet at design conditions due to steady flow and high efficiency. The residual circulation exits at downstream of the guide vane, and the circumferential velocity component increases linearly from hub to tip at small flow rate conditions. Hub leakage in adjustable blades results in the decrease of the meridional velocity and circulation at blade exit near hub. The results of numerical simulation and experiments supply important flow structure information for the high-efficiency axial-flow pump.
