PIV measurements of the unsteady flow structures in a volute centrifugal pump at a high flow rate
PIV measurements of the unsteady flow structures in a volute centrifugal pump at a high flow rate
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DOI：
10.1007/s00348-014-1820-7
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发表时间：
2014-09
影响因子：
2.4
通讯作者：
J. Keller;E. Blanco;R. Barrio;J. Parrondo
中科院分区：
文献类型：
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作者：
J. Keller;E. Blanco;R. Barrio;J. Parrondo
采用PIV技术对无叶蜗壳离心泵内的非定常流动进行了实验研究。该研究的重点是当泵在设计条件（150%的标称流量）以上运行时，与叶片通道周期相关的叶轮和蜗壳之间的流体动力学相互作用。测试泵是完全透明的，具有2D形状的几何形状，叶轮具有6个弧形向后弯曲的叶片。使用荧光播种颗粒和两个视场（FOV）捕获垂直于泵轴的中平面中的流动，每个视场具有不同的放大率：大FOV（低放大率），覆盖叶轮、蜗壳和排出管道的大部分，以及小FOV（高放大率），以观察舌部区域处的流动演变的细节。计算结果给出了平面内相平均相对速度和绝对速度、湍动能、湍动能产生和涡量场。描述了在一个叶片通道期间它们随时间的演变，包括基于32个叶片位置的频率分析。叶片通过频率和一些谐波的频谱分量的空间分布表明，二次谐波是占主导地位的在舌尖的蜗壳的狭窄区域。所获得的数据表明，流体动力学叶片-舌相互作用主要由从叶轮通道，特别是从叶片后缘脱落的高涡量片（正和负）以及它们对舌尖的冲击和随后的切割和变形所控制。湍流的产生主要集中在叶片前缘和后缘以及舌尖的尾流区域。特别是，当叶片与舌尖对齐时，它在叶片后缘后面达到最大值。
An experimental investigation based on PIV measurements is presented on the unsteady flow in a centrifugal pump with vaneless volute. The study has focused on the fluid–dynamic interaction between impeller and volute associated with the blade passage period when the pump operates well above design conditions (150 % of nominal flow rate). The test pump, which is fully transparent, has a 2D-shaped geometry and the impeller has 6 arc-shaped backward-curved blades. The flow in the mid-plane perpendicular to the pump axis was captured using fluorescent seeding particles and two fields of view (FOV), each with different magnification: a large FOV (low magnification) that covers a large portion of the impeller, volute and discharge duct, and a small FOV (high magnification) to observe the details of flow evolution at the tongue region. Results are presented on the in-plane phase-averaged relative and absolute velocities, turbulent kinetic energy, its production and vorticity fields. Their evolution over time during one blade passage is described, including a frequency analysis based on 32 blade positions. The spatial distribution of the spectral components at the blade-passing frequency and some harmonics reveals that the second harmonic is dominant in the narrow region of the volute at the tongue tip. The data obtained show that the fluid–dynamic blade–tongue interaction is dominated by high-vorticity sheets (positive and negative) being shed from the impeller channels, especially from the blade trailing edges, and their impingement on the tongue tip with subsequent cutting and distortion. The turbulence production is seen to be mainly concentrated in the wake regions from the blade leading and trailing edges and from the tongue tip. In particular, it gets maximum behind the blade trailing edge when the blade aligns with the tongue tip.