出口角对离心油泵叶轮切割定律影响的实验研究

【作者】 蔡永雄；

【导师】 李文广；

【作者基本信息】 兰州理工大学 ， 流体机械及工程， 2004， 硕士

【摘要】 本文工作系兰州理工大学校科技基金资助项目的一部份。叶轮切割是调整定转速离心油泵水力性能的重要方法之一。因此，研究叶轮切割直径后，泵性能变化规律对离心油泵高效运行，降低用户电能消耗，丰富离心油泵工作理论，都具有一定的现实意义。本课题组陆续在65Y60型离心油泵原配叶轮切割定律及叶片数的影响等方面作过一些试验研究。研究表明，在离心油泵设计时，叶片出口角的选择范围较大。因此不同泵厂设计出的叶轮出口角可能不同。那幺不同出口角叶轮切割后，泵性能还服从相同的变化规律吗?本文试图对该问题进行试验研究。本文选取油田和炼油厂常用的低比转速离心油泵65Y60型为研究对象，针对出口角分别为15°、30°、45°和60°的叶轮，采用试验方法，研究了不同粘度下叶轮切割后离心油泵性能的变化情况。根据试验数据，分别计算了关死工况下扬程、轴功率切割指数以及最优工况下流量、扬程、轴功率和效率切割指数。分析了不同出口角叶轮切割后性能和切割指数的差异。得到了以下研究成果：(1) 叶轮在第一次切割后，泵最优工况点的效率有所上升，出口角越大效率上升的幅度越大。如果输送的是粘油，随着粘度的增大，效率上升也越大。(2) 关死工况下，不同出口角叶轮的扬程和轴功率切割指数近似等于某一个不同的常数。(3) 输送粘油时，最优工况下，扬程切割指数与关死工况下的比较接近。但是不同出口角叶轮的扬程切割指数变化程度不一样。(4) 输送粘油时，一定范围内出口角越大效率切割指数越小。(5) 叶轮切割指数与直径比的确存在着某种关系，也就是切割指数随着切割后的直径比的变化而变化。更多还原

【Abstract】 The work is one part of a project that was supported by the Scientific and technological research fund at Lanzhou University of Technology.Impeller trim is an important way to adjust hydraulic performance of centrifugal oil pumps with constant motor speed. Thus, the investigation into the pump performance variation with various impellers trimmed has a practical signification to maintain the pump operating in a high efficiency, to reduce its electricity consumption and to enrich its flow theory and performance features.This research group did some experiment researches in the affinity law of impeller trim and the influence of number of blades on the law etc for the original impeller of centrifugal oil pump of type 65Y60 in succession.It has been shown that there is a large choice interval for blade outlet angle when a centrifugal oil pump being designed. This will cause the blade outlet angle of the pump made by one manufactory would differ from that by another. Does the performance variation with impeller diameter trimmed still share the same affinity law for the pumps with different blade outlet angles? The present thesis will attempt to attack this research issue by experiments. The centrifugal oil pump of type 65Y60 with low specific speed, which have been applied extensively in oilfields and refineries in China, is selected the test model. The pump performance variations with impeller diameter trimmed have been studied experimentally under various viscosities of liquids for the impellers with outlet angles of respective 15 , 30 ,45 and 60. Based on the experimental data, the trim exponents of head and shaft power in shut-off points and exponents of flow rate, head, shaft power and efficiency in best efficiency points have been worked out. The discrepancy in both performance and trim exponent among the impellers with different outlet angles has been analyzed. Based on the results of the investigation, the following conclusion should be made:(1) When the impeller is cut in first time, the pump efficiency rises at best efficiency points. The larger the blade outlet angle is, the greater the efficiency rises. If the pump handles viscous oil, the efficiency rises greatly as the viscosity increases.(2) The trim exponents of head and shaft power of the impeller with different outlet angles approximately are equal to different constants respectively at shut-off points.(3) When handling viscous oil, the trim exponents of head in best efficiency points is close to that at shut-off points. However, the trim exponent variations of head of impellers with different outlet angles differ from each other.(4) When pumping viscous oil, the larger blade outlet angle will result into smaller trim exponents in a certain viscosity range.(5) There is a relationship between the trim exponents and impeller diameter ratio, namely the exponents vary with the ratio.更多还原