多级离心泵叶轮和导叶匹配关系的研究

发布时间：2018-04-11 13:21

本文选题：多级离心泵 + 水力优化设计　；参考：《兰州理工大学》2017年硕士论文

【摘要】：低比转速离心泵小流量、高扬程的特点使泵的效率普遍偏低。叶轮和导叶的匹配关系对泵的性能产生一定影响,因此在设计泵时需要考虑二者的匹配关系。本文以100×80(G)TDF10GM型节段式多级离心泵为背景,通过理论分析和数值计算,对叶轮和导叶的匹配进行优化,提升泵的性能,同时得到了二者匹配的最优关系式。首先,根据速度系数法对原叶轮和导叶进行水力计算,针对低比转速离心泵自身效率低、易过载和扬程曲线易出现驼峰的特点,在原叶轮和导叶匹配关系的基础上运用面积比原理重新设计导叶入口喉部面积。对原泵型进行三维定常计算并通过试验验证了数值模拟的可靠性。理论上分析了正导叶叶片数Z、正导叶叶片进口安放角3a和导叶入口喉部平面宽度a3之间的关系,确定通过改变a3值来设计导叶入口喉部面积。在此基础上改变导叶基圆直径D3来优化叶轮外径与导叶基圆直径的间隙T,最终确定面积比Yd=0.434m,间隙T2=6mm时,泵的性能得到提升,四级装配的模型泵其效率较原四级泵型提高了4.5%,扬程几乎没变,轴功率有所降低,达到了优化的目的。对非设计工况下不同优化模型泵的内部流动情况和叶片工作面上静压分布展开研究,明确了叶轮和导叶的匹配对整个上下游流道的流动都产生影响。随着流量的增加,加大导叶入口喉部面积和间隙都会使叶片工作面静压值降低,表明叶轮的流通性更加顺畅,从而进一步揭示了二者的匹配是影响泵性能的重要因素。综合考虑面积比和间隙两种匹配关系,最终得出导叶单流道下入口喉部面积F_(ab)、导叶基圆直径D_3与叶轮外径D_2的关系式,使用该式设计导叶可以避免由传统速度系数法设计带来的误差。本文的研究成果对该泵型的设计具有一定的指导意义。
[Abstract]:Low specific speed centrifugal pump small flow, high head characteristics of pump efficiency is generally low.The matching relationship between impeller and guide vane has a certain effect on the pump performance, so the matching relationship between the impeller and the guide vane should be considered when designing the pump.Based on the #number0# 脳 80(G)TDF10GM multistage centrifugal pump, the matching of impeller and guide vane is optimized by theoretical analysis and numerical calculation, the performance of the pump is improved, and the optimal relationship between them is obtained.First of all, according to the speed coefficient method, the hydraulic calculation of the original impeller and guide vane is carried out, aiming at the characteristics of low specific speed centrifugal pump with low efficiency, easy overload and easy to appear hump in the lift curve.Based on the matching relationship between the original impeller and the guide vane, the area of the inlet throat of the guide vane was redesigned by using the area ratio principle.The reliability of the numerical simulation is verified by three dimensional steady calculation of the original pump model.The relationship between the number of positive vanes Z, the inlet placement angle 3a of the positive guide vane and the plane width a3 of the inlet throat of the guide vane is analyzed theoretically, and the area of the inlet throat of the guide vane is determined by changing the A3 value.On this basis, the clearance T between the outer diameter of the impeller and the diameter of the base circle of the guide vane is optimized by changing the diameter of the guide vane base circle D3, and the area ratio is determined to be 0.434 m. When the clearance T2=6mm is changed, the performance of the pump is improved.The efficiency of the model pump is 4.5 higher than that of the original four-stage pump, the lift is almost unchanged, the shaft power is reduced, and the purpose of optimization is achieved.The internal flow of different optimization models and the distribution of static pressure on the blade face under off-design conditions are studied. It is clear that the matching of impeller and guide vane has an effect on the flow of the whole upstream and downstream passage.With the increase of flow rate, increasing the area and clearance of the inlet throat of the guide vane will decrease the static pressure value of the blade face, which indicates that the flow of the impeller is more smooth, which further reveals that the matching of the two factors is an important factor affecting the pump performance.Considering the matching relationship between area ratio and clearance, the relationship between the throat area of the lower entrance of the guide vane and the diameter D3 of the base circle of the guide blade and the outer diameter of the impeller is obtained.The error caused by the traditional velocity coefficient method can be avoided by using this formula to design the guide vane.The research results of this paper have certain guiding significance to the design of the pump type.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH311

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