叶轮相位交错对多级离心泵非定常外特性的影响

Study of the Influence of the Staggering Arrangement of Impellers in Various Phase Positions on the Unsteady External Characteristics of a Multi-stage Centrifugal Pump

以6级离心泵为模型，设计了同轴布置的6级叶轮相位不交错（方案A）、交错一个流道相位的1／2（方案B）、交错一个流道的1／（Z-1）（Z为叶轮叶片数，方案C）、交错一个导叶流道的1／（Z1-1）（Z1为导叶数，方案D）的4种方案，在UG软件中完成三维模型建立，采用标准k—ε湍流模型，利用ANSYS—CFX软件进行了三维全流场的非定常计算。研究表明：不同方案的外特性虽然相差不大，但叶轮相位交错改变了叶轮之间的相对位置关系，使外特性的相位同步发生时序性变化；在0．6Qd、1．0Qd工况下方案B的内部激励叠加效果优于方案A；在1．4Qd工况下内部激励强度在减弱，叶轮相位交错影响了该工况下扬程波动的主频；在设计工况下效率的波动幅值最大，在偏设计工况条件下方案B、方案C的效率相对比较稳定；同时，3个计算工况条件下方案B、方案C的轴功率波动幅值比较稳定。而在大流量工况下方案B的非定常轴功率最稳定。

With a six-stage centrifugal pump serving as a model, designed were four versions, namely, co- axial arrangement of six impellers with their phase positions being not staggered （Version A）, coaxial ar- rangement of six impellers with their phase positions being staggered by 1/2 of the arc length of a flow passage （Version B）, coaxial arrangement of six impellers with their phase positions being staggered by 1/（Z - 1 ） of the are length of a flow passage （Z is the number of blades on an impeller,Version C） ,co- axial arrangement of six impellers with their phase positions being staggered by 1/（ Z1 - 1 ） of the arc length of a flow passage （Z1 is the number of guide blades, Version D）. After a three dimension model had been established in the software UG,an unsteady calculation of the three dimension whole flow field was performed by using the standard k -8 turbulent flow model in the software ANSYS-CFX. It has been found that although various versions have not a big difference in their external characteristics, the stagger- ing of the phase positions of the impellers makes the relationship among their relative positions changed and forces the time sequence of the external characteristics synchronized by the phase positions also changed. Under the operating conditions of 0.6Qd and 1.0Qa, the internal excitation and superposition ef- fectiveness of the Version B is superior to that of Version A. Under the operating condition of 1.4Qd, the internal excitation intensity will become weakened and the staggering of the phase positions of the impel- lers will affect the main frequency of the head in fluctuation. Under the design operating condition, the fluctuation in the efficiency will be the maximum. Under the off-design operating condition, the fluctuation in the efficiency of the Version B and C will be relatively stable. At the same time, under the three calcu- lation conditions, the fluctuation in the shaft power of the Version B and C will be relatively stable, howev- er, under the operation condition of a big flow rate, the unsteady shaft power of the Version B will be the most stable.