【作者】 郭晓梅；

【导师】 朱祖超； 崔宝玲；

【作者基本信息】 浙江理工大学 ， 机械设计及理论， 2013， 博士

【摘要】 高速离心泵在高速下运行，离心叶轮极易发生空化，空化的发生会造成离心泵性能的下降，产生空蚀破坏，同时也会使机组的振动加剧，严重时甚至会产生灾难性的后果。目前，防止高速离心泵发生空化的最有效的途径之一是在高速离心主叶轮前加装一诱导轮，因此对离心泵和诱导轮内的空化展开研究是一项有意义并且很有必要的课题。目前，对旋转空化两相流的研究仍处于探索之中，尤其是水力机械和诱导轮内的空化流动机理尚未完全明确，揭示空化流动的机理是学术界和工程界都需要急待解决的一个问题。本文在国家自然科学基金项目（NO.51076144）、浙江省自然科学基金项目（NO. Y1100013）和浙江省公益工业类项目（NO.2012C21013）的资助下，从理论分析、数值计算、外特性性能实验和可视化实验等方面入手对该高速离心泵和诱导轮内的空化演变过程、空化流动机理等进行了较为系统的研究分析。论文首先开展了非汽蚀状态下的单相流动数值计算，揭示了设计工况点下和不同工况点下前置各诱导轮时高速离心泵内的流动机理。其次，开展了汽蚀状态下的旋转空化流动的数值计算，揭示了设计工况点和不同转速工况点下前置各诱导轮高速离心泵内的旋转空化现象，揭示了在不同空化系数下空化发展的过程。再次，以前置诱导轮的高速离心泵为研究对象进行了外特性性能实验，得到了多工况下，在前置各诱导轮情况下该高速离心泵的性能曲线；最后对诱导轮内的旋转空化进行了可视化研究，进一步揭示了空化的时空演化规律。综上所述，本文主要结合数值计算、外特性实验及可视化实验三种研究手段，进行了对比分析、验证，证明了本论文研究方法的可行性和结论的正确性。论文的主要研究工作如下：（1）进行了高速诱导轮离心泵在非汽蚀状态下的单相流动计算。以外特性实验结果做为边界条件，在设计工况点和各转速相似工况点下，对前置各种诱导轮的高速离心泵进行了单相流动数值计算，通过计算得到了诱导轮和离心泵内的压力分布情况，得到了叶轮内和诱导轮内的最低压力情况，揭示了在非汽蚀状态下诱导轮和高速离心泵内部流动的情况。（2）进行了高速诱导轮离心泵汽蚀状态下旋转空化流动的数值计算。对前置各种诱导轮的高速离心泵进行了旋转空化流动的数值计算，通过计算揭示了在汽蚀状态下，诱导轮和高速离心泵主叶轮在设计工况点和不同转速工况点下的旋转空化现象，揭示了诱导轮和主叶轮在不同空化系数下空化发展的过程。（3）开展了前置各种结构诱导轮高速离心泵的外特性性能实验研究。通过实验，得到了各转速相似工况（转速为2000r/min～8000r/min）下的外特性性能曲线；对各种诱导轮的抗汽蚀性能进行了分析比较，得到了抗汽蚀性能较好的诱导轮为变螺距诱导轮，得到了叶片数相对较佳的变螺距诱导轮为三叶片变螺距诱导轮；对各转速下的相似工况点进行了汽蚀实验，得到了其抗汽蚀性能随着转速的增加而降低的结论。（4）开展了分流叶片诱导轮内旋转空化的可视化研究。通过高速摄像图片的分析，进一步揭示了诱导轮内空化发生的位置、空化发生的程度等，进一步揭示了空化的时空演化规律。更多还原

【Abstract】 As the centrifugal pump runs at a high speed, the centrifugal impeller is easy to cavitate.The occurrence of cavitation will destroy the centrifugal pump’s performance, cause cavitationdamage, aggragate the unit vibration, and sometimes even can cause disastrous consequences. Atpresent, one of the most effective ways to prevent the high-speed centrifugal pump cavitation isto equip an inducer before the centrifugal impeller. Thus to research the cavitation of thecentrifugal pump and inducer is important and necessary. At present, the research of rotatingcavitation flow is still in the period of exploration. Especially the cavitation flow mechanism ofhydraulic machinery and the inducer is not completely clear. In the field of the academic andengineering, to reveal the mechanism of cavitation flow is a problem needs to resolve urgently.This paper is supported by the National Natural Science Fund Project (NO.51076144), NaturalScience Foundation of Zhejiang Province (NO. Y1100013) and Public Industrial Projects ofZhejiang Province (NO.2012C21013). Based on the theoretical analysis, numerical calculation,external characteristics experiments and visualization experiments, the high-speed centrifugalpump and inducer cavitation evolution, cavitation flow mechanism are analyzed systematicallyin this paper.Firstly, Single-phase flow numerical calculation under non-cavitation state is carried out,and the mechanism of flow in the centrifugal pump and inducer is revealed on the design workcondition and on the different work conditions. Secondly, rotation cavitation flow numericalcalculation under cavitation state on different work conditions is done. The mechanism ofrotation cavitation flow is revealed. Thirdly, the performance experiments of high-speedcentrifugal pump with different inducers is carried out on different working conditions, and theperformance curves are got. Finally, the cavtitation visual experiment are carried out, and theevolution rules of cavitation are revealed further. In this paper, numerical calculation, externalperformance and visualization experiment are combined, tested and verified, which proved thefeasiblility of the research method and the correct of the conclusion.The main research work is as follows.（1）Single-phase flow numerical calculation under non-cavitation state on different workconditions is carried out. Taking the results of the external performance experiment as boundaryconditions, single-phase flow of the high-speed centrifugal pump with different inducers are simulated numerically, on design work condition and different work conditions. The pressuredistribution in the centrifugal pump and the inducers are got. The lowest pressure in the pumpand inducers are got. The flow mechanism in the impeller and the inducer under non-cavitationcondition is revealed.（2）Rotation cavitation flow numerical calculation under cavitation state on different workconditions is done. Rotation cavitation flow under cavitation state on different work conditions inthe centrifugal pump with different inducers is done. The rotating cavitation phenomenon isrevealed, with different inducers and under different work condtions. The cavitation developmentprocess in the inducer and impeller under different cavitation coefficient is revealed.（3）The performance experiments of high-speed centrifugal pump with different inducersare carried out. The experiments are under different working conditions. Through the experiment,the external performance curve of pump is got, which the rotational speed is from2000r/min to8000r/min. The inducer with good anti-cavitation performance is variable-pitch inducer. Thevariable-pitch inducer with three blades has better anti-cavitation performance. The experimentsof the pump on the similar conditions under different rotation speed are carried out, and theresults show that the anti-cavitation performance is reduced with the increase of the rotation.（4）The cavtitation visual experiments are carried out. The evolution rules of cavitation,the location of cavitation and the degree of the cavitation are revealed further. Visualization wascarried out to study the splitter inducer of rotating cavitation by analyzing the high speed videocamera pictures.更多还原