In this work, the behaviors of flow field and pressure fluctuations in both time and frequency domains in an axial flow pump through changing various impeller blade angles are studied and investigated by using a CFD technique. The blade angles are changed between 30°, 45o, 60o and 75o. Numerical results are validated with the experimental values, as a good agreement was found between them. The developed flow analysis shows that the blade angle does influence the different flow behaviors and features, such as the static pressure, turbulent kinetic energy (TKE), pressure fluctuations, axial velocity, radial velocity and tangential velocity. The results have revealed that the TKE rises with flow rate decreases and high static pressure increases at the pump outlet region near the tip blade region. Another conclusion of the study is the fact that the blade angle with 60o is the better one in terms of lower-negative-pressure regions, when compared with the other settings. The first dominated frequency was pump rotational frequency, and the second important frequency is the BPF (blade passing frequency). Furthermore, the results showed that impeller blade angles and unsteady flow have a high influence on the pressure fluctuation amplitude. Moreover, the results of the presented numerical simulation would be useful for a future hydraulic design of an axial pump.

中文翻译：

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基于时域和频域研究的不同叶轮叶片角度对压力波动轴流泵特性的影响分析

在这项工作中，使用 CFD 技术研究和研究了通过改变各种叶轮叶片角度，轴流泵中时域和频域的流场和压力波动的行为。叶片角度在 30°、45o、60o 和 75o 之间变化。数值结果与实验值进行了验证，因为它们之间存在良好的一致性。开发的流动分析表明，叶片角度确实会影响不同的流动行为和特征，例如静压、湍动能 (TKE)、压力波动、轴向速度、径向速度和切向速度。结果表明，在靠近叶尖区域的泵出口区域，TKE 随着流速的降低而升高，并且高静压增加。研究的另一个结论是，与其他设置相比，60o 的叶片角度在较低负压区域方面更好。第一个主导频率是泵旋转频率，第二个重要频率是 BPF（叶片通过频率）。此外，结果表明叶轮叶片角度和非定常流动对压力波动幅度有很大影响。此外，所提出的数值模拟的结果将有助于轴流泵的未来水力设计。结果表明，叶轮叶片角度和非定常流动对压力波动幅度有很大影响。此外，所提出的数值模拟的结果将有助于轴流泵的未来水力设计。结果表明，叶轮叶片角度和非定常流动对压力波动幅度有很大影响。此外，所提出的数值模拟的结果将有助于轴流泵的未来水力设计。