Department of Mechanical Engineering, Faculty of Engineering, Mustansiriyah University, Baghdad, Iraq
In this current study, the transient numerical calculations using CFD are carried out under different number of impeller blades for the flow field within a centrifugal pump under single-phase and cavitation condition. Both qualitative and quantitative analyses have been carried out on all of these results in order to better understand the flow structure within a centrifugal pump under both single-phase and cavitation. Also, the investigation using different number of impeller blades relating to the static pressure, velocity magnitude and vapour volume fraction variations have been analysed. Fluctuations pressure in both time and frequency domains at the impeller and volute of the pump also investigated. As a result, the pressure and velocity were gradually increased from inlet to outlet of the pump. Pressure at the impeller outlet was higher than the pressure at other parts due to high interaction between impeller and volute tongue region. The distribution of volume fraction first occurs at the inlet eye of impeller. Furthermore, the cavitation increases as the number of impeller blades and flow rate increase. The length of the cavity was increased when low pressure at the inlet impeller (eye) decreased at Z=5 blades cavitation was affected highly at the suction of impeller compared to other number of blades particularly at high flow rate.