中文摘要：

为研究小流量下离心泵的空化特性,采用ANSYS CFX 14.5,基于k-ε湍流模型和Rayleigh-Plesset空化模型,以3种叶片数叶轮的IS50-65-160型离心泵为研究对象,对其内部空化流动分别进行了数值模拟。为了提高数值计算准确性,进行了网格无关性分析,且从泵空化性能、叶轮所受扭矩及轴向力分析了叶片数对泵小流量下空化特性的影响规律。研究结果表明：当叶片数从4增加至8时,离心泵扬程增加,但其效率变化较复杂。小流量工况下,随着空化系数降低,各叶片数叶轮扭矩与泵扬程均不同步地发生陡降,且出现相似地匍匐下降规律;当扬程下降3%后,各叶轮所受轴向力的大小几乎恒定;单个叶片流道的空泡体积出现突增,明显较其他叶片流道大,各叶片流道空泡分布极不对称。研究发现,离心泵扬程及扭矩匍匐下降特性很可能与不对称叶片空化相关。

英文摘要：

In order to investigate the cavitation characteristics of centrifugal pumps under low flow rates, the cavitating flows in the centrifugal pump typed IS50 - 65 - 160 with three different blade-number impellers were numerically simulated based on the k-e turbulent model combined with Rayleigh -Plesset cavitation model by using the software ANSYS CFX 14.5. Meanwhile, grid independence check was carried out to verify the accuracy of calculation. The effect of blade numbers on the cavitation characteristics in the pump was firsdy analyzed from the points of suction performances, torque as well as axial forces acted on impellers. The results showed that as the blade number increased from 4 to 8, the pump head increased while the variable regulation of its efficiency was quite complicated. Both the head- drop and torque-drop curves of impellers with three different blade numbers had the same shape of creeping dropping, with the corresponding break-down points occurring asynchronously. The axial forces acted on impellers almost kept constant as the amount of head dropping was 3% or higher. The vapor volume in one blade was larger than others, and finally a significantly asymmetric distribution occurred on all blades. It was firstly obtained that the creeping-drop characteristics of both pump head and torque acted on the impellers were possibly related to onset of asymmetric blade cavitation phenomenon. Moreover, this study to some extent can also provide some reference for the design of centrifugal pump in the industry in case of avoiding serious cavitation occuring at low flow rates.