Abstract: To study the characteristics of a self-priming pump, differences and patterns in its internal flow and self-priming time at different blade numbers are examined. We have built a visual experiment platform and studied its self-priming process via direct experimental observation. Through comparison and analysis between the designs of double, three and four blades, time evolution of the gas-liquid two-phase flows and distributions of the gas and liquid phases in different operation stages are studied, further revealing the influence mechanism of the blade number on self-priming time. In the experiment, a high-speed camera is also used to take photographs of the internal flows in the pump, so that we can explore the processes of gas-liquid mixing, gas-liquid separation, and gas-liquid reflux at different blade numbers more thoroughly, thus to reveal how the number of blades influences the gas-liquid two-phase flow pattern in each self-priming stage to improve self-priming pump impellers.

Key words: self-priming pump, self-priming performance, number of blades, visualization experiment