基于CFX的双向立式轴流泵装置水力性能分析

为分析双向立式轴流泵装置的内部流动结构并进行性能预测,应用三维紊流Navier-Stokes、RNG k-ε湍流模型和壁面定律对泵装置进行全流场数值模拟研究,共计算了额定转速下240—460L/s流量范围内的9个工况点.分析了导水锥对进水流道水力性能的影响及导叶体对装置性能的影响,并通过泵装置模型试验对预测的外特性结果进行验证.研究表明,加设导水锥可消除喇叭口下的奇点,避免附底涡的产生,加设导水锥后进水流道出口断面轴向速度分布均匀度提高0.5—0.8个百分点,速度加权平均角提高了0.3°—1.28°.导水锥对自流工况的影响很小.大流量工况时扩散导叶对叶轮出口环量的回收效果优于常规导叶,泵装置效率明显提高.

Analysis on Hydraulic Performance of Reversible Vertical Pumping System Based on CFX

The investigation of the three-dimensional fluid flow inside a reversible pumping system was made based on the Reynolds time-averaged Navier-Stokes equations,the RNG k-ε turbulent flow model and the law of the wall.The performance calculations were made at 9 operation points within flow rates range 240—460L/s under the rated rotating speed.The effects of flow guide cone on the hydraulic performance of inlet passage and the effects of guide vane on the performance of pumping system were analyzed.To verify the accuracy and reliability of the calculation results,a model test was conducted.The singular point which caused the submerse vortex under pump suction were eliminated by flow guide cone.With the flow guide cone,the axial velocity distribution uniformity at the exit section of suction passage was improved by 0.5—0.8 percentage points,and velocity-weighted average swirl angle increased by 0.3°—1.28°.Flow guide cone has little effect on water flow by gravity.Diffuse shape guide vane can better recover circulation out from impeller at large flow rate,therefore the efficiency of pumping system increased obviously.