叶片进口边穿孔对离心泵空化性能的影响

Effect of blade perforation near inlet edge on cavitation performance of centrifugal pump

为了研究叶片进口边位置附近穿孔对离心泵非定常空化性能的影响规律,以某离心泵为研究对象,在叶片进口边同一位置设计了10种孔径大小不同的圆孔,基于SST k-ω湍流模型和Zwart空化模型,分别对这10种叶轮的离心泵进行清水介质下的全流道三维非定常数值模拟,并同试验结果进行对比.研究发现,对于低比转数离心泵而言,在进口边气泡最先产生的位置进行叶片穿孔(该位置距叶片头部距离约占整个叶片长度的1/30),当穿孔直径为8 mm时,不仅扬程、效率得到提高,而且可显著地提高离心泵的空化性能;穿孔叶片将每个叶轮流道内整体的空化区截断成了2个空化区,随着孔径的增大,叶轮内低压区分布范围先减小后增大,当孔径为 8 mm 时,低压区的分布范围最小;叶片穿孔后叶轮内压力脉动幅值明显大于原型叶片且穿孔对流场的影响作用随着与穿孔位置距离的增大而逐渐减弱,在蜗壳内穿孔对流场的影响作用完全消失.

In order to explore the influence of the blade perforation near the inlet edge on cavitation performance of a centrifugal pump, a low specific speed centrifugal pump was selected as the research object. Ten different sizes of pores were designed in the same place of blade inlet edge of the centrifugal pump. Based on SST k-ω turbulent model and Zwart cavitation model, under the condition of water medium, 10 different impellers were numerically simulated in the full flow passage and compared with the experimental results. The research shows that the blade perforation with the diameter of 8 mm near the inlet edge, which is the first place to generate bubbles, improves head, efficiency and cavitation performance remarkably. The blade perforation divides the general cavitation region into two in every flow passage. With the increase of pore, the low pressure area in runner reduces, then increases. The distribution of low-pressure area is the smallest when the diameter is 8 mm near the blade inlet edge. The amplitude of pressure fluctuation of perforated blade is apparently larger than that of prototype blade. With the increase of perforated position distance,the influence of perforated blade on flow field gradually decreases and disappeares completely at last in the volute.