Comparative Experiments on a Self-priming Pump Delivering Water Medium During Rapid and Slow Starting Periods

Abstract

This paper presents an experiment on the transient hydraulic performance of a self-priming pump for transporting clear water under fast and slow start-up states. In the experiment, five typical working conditions are set, and the evolution of preset rotating speed increases linearly. The similarities and differences between fast and slow start-up states are analyzed in detail. Results show an overall flow volume curve that presents three segment evolution characteristics in the start-up process. The inlet static pressure exhibits three drops and two rises in the fast start-up state and two drops and two rises in the slow start-up state. The dimensionless discharge coefficient is closely related to steady flow condition. The dimensionless head coefficient has little correlation with steady flow condition. The dimensionless power coefficient is almost independent of steady flow condition. The pump similarity law is especially unsuitable for the first half of the start-up process when the steady flow volume is small as well as for the latter half of the process when the steady flow volume is large. In the start-up process, the parameters can be arranged from serious to slight under the influence as follows: flow volume, rotating speed, and head of delivery.