Simulation of transient two-phase flow in the centrifugal pump during start-up time and evaluation of effective parameters on the performance of the pump

Centrifugal pumps in most industries are responsible for transporting fluids and significant role in the amount of energy consumed. One of the most important issues in explaining centrifugal pumps is the start-up stage. As this point, the pump performs at transient mode. The period when it is necessary for the pump to rotate at a constant speed is called the start-up time of the pump. All the start-up stage, hydraulic equipment may be damaged due to pressure fluctuations. Therefore, it seems necessary to study the performance of the pump at transient stage. In the present study, using the computational fluid dynamics tools, the performance of the pump during the start-up period has been studied. The result show that due to the increase in pump start-up time, the maximum pressure created in pump decreases. And by increasing the length of the pipe downstream, the amount of pressure created in the pump increases. Finally, by adding a certain amount of impurities to the water and performing a two-phase flow analysis, the power required by the pump increases.