Investigation of the Main Flow Characteristics Mechanism and Flow Dynamics Within an Axial Flow Pump Based on Different Transient Load Conditions

Easy implementation and considerable equipment cost savings, encourage the engineers to use pump as a turbine for both water supply systems and small-scale hydroelectric plants. Flow dynamics in the pumps which are used as turbines are not considered well, and one important disadvantage of them is their incapacity to control flow. This study investigates the mixed-flow dynamics of axial pumps under five operational conditions, from optimal (1.0 QBEP) to the QBEP plus value (20 l/min). In addition, three angles are considered, namely − 3°, 0°, and 3°, to examine the effects of blade angle on them. The flow stability of the axial pump deteriorated as the flow decreased, while pressure pulsations in different flow regions became more intense. Increasing the runner blade angle from − 3° through 0° to 3° influenced the machine's flow and pressure field characteristics. As a result of this increased blade angle, flow unsteadiness and pressure pulsation levels also increased, and the rotor–stator interaction frequencies became dominant in most flow regions. Researchers and engineers will greatly benefit from this study since it contributes to a more thorough understanding of pump flow dynamics.