叶轮切割方式对IS 100-65-200型离心泵性能的影响

Effects of impeller cutting ways on performances of IS 100-65-200 type centrifugal pump

采用Fluent软件在双参考坐标系下,利用有限体积法对雷诺时均Navier Stokes方程进行数值离散,选用标准k-ε湍流模型,SIMPLEC方法求解,对IS 100-65-200型离心泵在不同叶轮切割方式下的内部流场进行了叶轮和蜗壳的耦合数值模拟。根据数值模拟结果预测IS 100-65-200型离心泵的性能,并分析不同叶轮切割方式对泵内部流场的影响。结果表明:泵的扬程、轴功率和效率受切割方式的影响明显,相同切割量下,随着切割角度的增加,扬程先升高后降低,切割角度θ在0°～20°的范围内扬程达到最高;轴功率先升高后降低,θ在20°左右时达到最高。反向斜切达到的最高效率和扬程明显高于正切和正向斜切,正向斜切达到的最高轴功率明显高于反向斜切和正切。内部流场分析表明:在相同外特性下,反向斜切时叶轮内低压区面积小于正切和正向斜切,提高了泵的性能,同时,反向斜切减小了隔舌处的回流,提高了泵的效率。不同切割方式下,切割前后叶轮出口相应位置处速度三角形并不相似。考虑切割角度的大小,对现有切割公式进行了修正和验证。

In different cutting ways, the flow field in 100-65-200 type centrifugal pump was simulated by Fluent software. The standard k-ε turbulence model and SIMPLEC algorithm were chosen in FLUENT. The simulation was steady and the moving reference frame was used to consider rotor-stator interaction. Accord- ing to the simulation results, effects on the internal flow in 100-65-200 type centrifugal pump with different impeller cutting ways were analyzed and the performances of the centrifugal pump were predicted. The results showed that the head, the shaft power and the efficiency of the pump were affected by the cutting way. With the increasing of the cutting angle, the head and the power were increased at first and then decreased on the same cutting value. When the cutting angle was from 0° to 20°, the head value reached the highest one. When the cutting angle was about 20°, the power value reached the highest one. The highest efficiency and the head in the reverse miscut were obviously higher than that in the straight cut and positive miscut. The highest shaft power in the positive miscut was obviously higher than that in the reverse miscut way and straight miscut. The the inner flow analysis results indicated that, with the same external characteristics, the low-pressure area of the reverse miscut in the impeller was smaller than the tangent and the positive miscut, so the centrifugal pump performance was improved. Meanwhile, the reverse miscut reduced backflow at the tongue and enhanced the efficiency of the pump. In different cutting ways, the speed triangles at corresponding position of impeller outlet were not similar before and after impeller cutting. Considering different cutting angles, the existing cutting formula was revised and verified.