The Effect of Impeller Cutback on the Fluid-Dynamic Pulsations and Load at the Blade-Passing Frequency in a Centrifugal Pump
The Effect of Impeller Cutback on the Fluid-Dynamic Pulsations and Load at the Blade-Passing Frequency in a Centrifugal Pump
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DOI：
10.1115/1.2969273
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发表时间：
2008-11
影响因子：
2
通讯作者：
R. Barrio;E. Blanco;J. Parrondo;J. González;Joaquín Fernandez
中科院分区：
文献类型：
--
作者：
R. Barrio;E. Blanco;J. Parrondo;J. González;Joaquín Fernandez
研究了单吸无叶蜗壳离心泵中由于叶片与蜗壳相互作用而产生的流体动力脉动和相应的动力。试验泵中依次考虑了四个不同出口直径的叶轮，将最大的叶轮逐级缩小（修整），使叶轮与蜗壳之间的径向间隙为叶轮半径的8.8%~23.2%。该研究基于使用 FLUENT 代码对多种流速下流经机器的非定常流动进行数值计算，求解 3D 非定常雷诺平均纳维-斯托克斯方程。此外，还对带有一个叶轮的泵进行了一系列实验测试，以获得沿蜗壳前壁的压力波动数据，从而与数值预测进行对比。从数值计算中收集的数据用于估计叶片通过频率下的动态径向力和扭矩，作为流速和叶片舌部径向间隙的函数。正如预期的那样，对于给定的叶轮直径，动载荷在非设计条件下会增加，特别是在低流量范围内，而叶轮舌间隙的逐渐减小会带来动载荷的相应增量。特别是，在本研究的限制范围内改变叶片舌间隙，导致叶片通过频率径向力的最大幅度在低流量（即低于标称流量）时乘以约 4 倍，在高流量时乘以 3 倍。
A study is presented on the fluid-dynamic pulsations and the corresponding dynamic forces generated in a centrifugal pump with single suction and vaneless volute due to blade-volute interaction. Four impellers with different outlet diameters, obtained from progressive cutbacks (trimmings) of the greatest one, were successively considered in the test pump, so that the radial gap between the impeller and the volute ranged from 8.8% to 23.2% of the impeller radius. The study was based on the numerical computation of the unsteady flow through the machine for a number of flow rates by means of the FLUENT code, solving the 3D unsteady Reynolds-averaged Navier-Stokes equations. Additionally, an experimental series of tests was conducted for the pump with one of the impellers, in order to obtain pressure fluctuation data along the volute front wall that allowed contrasting the numerical predictions. The data collected from the numerical computations were used to estimate the dynamic radial forces and torque at the blade-passing frequency, as a function of flow rate and blade-tongue radial gap. As expected, for a given impeller diameter, the dynamic load increases for off-design conditions, especially for the low range of flow rates, whereas the progressive reduction of the impeller-tongue gap brings about corresponding increments in dynamic load. In particular, varying the blade-tongue gap within the limits of this study resulted in multiplying the maximum magnitude of the blade-passing frequency radial force by a factor of about 4 for low flow rates (i.e., below the nominal flow rate) and 3 for high flow rates.