Analysis of the Effect of Various Impeller Blade Angles on Characteristic of the Axial Pump with Pressure Fluctuations Based on Time- and Frequency-Domain Investigations

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 degrees, 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.