变螺距诱导轮对高速离心泵空化性能的影响

Effects of variable pitch inducer on cavitation performance of high-speed centrifugal pumps

为了研究诱导轮的几何形状以及诱导轮与叶轮之间的相互配合对于高速离心泵的空化性能的影响,基于RNG k-ε模型和Schnerr-Sauer空化模型,对于高速离心泵在前置不同几何结构的变螺距诱导轮和多种诱导轮与叶轮的配合条件下进行了数值模拟.结果表明,与叶片直径线性变化的变螺距诱导轮相比,叶片直径为常数的变螺距诱导轮可以更好地改善高速离心泵的空化性能;诱导轮与叶轮直径轴向距离太小或者过大,将导致叶轮的压力系数与空化数减小,叶轮流道气相体积占比增加,高速离心泵的效率及扬程下降;另外,高速离心泵的空化性能随周向夹角改变而产生很大波动,但是变化规律不明显.

In order to study the effect of geometry shape of variable pitch inducer and coordination be- tween inducer and impeller including axial distance and circumferential angle on the cavitation perfor- mance of the high-speed centrifugal pump, the turbulence model of RNG k - e and cavitation model of Schnerr - Sauer were used to investigate the cavitation performance of high-speed centrifugal pump with different inducers at diverse coordination conditions. The results show that the variable pitch inducer whose blade diameter is constant can suppress the cavitation of the high-speed centrifugal pump more effectively compared with the variable pitch inducer with variable blade diameter. When the distance between inducer and impeller is too small or too large, the pressure coefficient and cavitation number of inducer decrease and the vapor volume ratio in the impeller flow channel has an upward trend. As a re- suit, efficiency and lift coefficient of the high-speed centrifugal pump decrease. In addition, the cavi-tation performance of tile pump fluctuates as the circumferential angle changes, however the change regularity is not obvious.