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通过对南水北调工程等比例缩放模型泵进行全流道数值分析和试验研究,对模型泵在3个典型流量工况下的空化计算进行适应性研究,探究叶轮区域的空化发展特性,并对不同叶顶间隙δ(0.5,1.5和3.0mm)下的轴流泵空化特性进行对比分析,比较叶顶间隙大小对轴流泵空化性能和流场的影响.结果表明:随着空化数的降低,空化首先在叶片进口边间隙区附近发生,逐渐往叶片出口边扩大,同时沿径向往叶片背面扩大最终覆盖整个叶片,引起叶片出口靠近叶顶间隙10%区域的轴向速度逐渐降低;随着叶顶间隙的增大,模型泵的临界空化数增大,叶片轮缘处空化逐渐严重且由叶片前端往尾部移动,叶片出口轴向速度低速区主要集中在靠近间隙10%区域处,揭示了这一过程不同叶顶间隙轴流泵内部空化特性.
Through the numerical analysis and experimental study on the full runner of the South-North Water Diversion Project, the adaptability of the model pump to the cavitation calculation under three typical flow conditions was studied, and the cavitation development characteristics of the impeller region were explored The cavitation characteristics of axial flow pump at different tip clearance δ (0.5, 1.5 and 3.0 mm) were compared and the influence of tip clearance on the cavitation performance and flow field of axial flow pump was compared. The results show that with cavitation The cavitation occurs first in the gap region near the inlet of the blade and gradually increases toward the blade exit edge. At the same time, the radial blade extends to cover the entire blade, causing the axial velocity of the blade exit near 10% of the blade tip clearance to gradually increase With the increase of tip clearance, the critical cavitation number of the model pump increases, the cavitation of the blade rim is gradually serious and moves from the tip of the blade to the tail. The low axial velocity of the blade outlet mainly concentrates near the gap 10 % Area, revealing the different cavitation characteristics of different tip clearance axial flow pumps in this process.