Effects of reflux hole on the performance of self-priming pump

Reflux hole plays an important role in the structure of the self-priming pump. Its position and area have a great influence on the self-priming capability and efficiency of the pump. In this paper, the numerical simulation of the internal flow field in the self-priming pump with different areas and positions of the reflux hole was conducted on the platform of Fluent. The simulation results show that when the pump works at design point, the larger the area of reflux hole, the higher the reflux flow rate flows into the volute through the reflux. And the self-priming capability is better. When the flow rate is larger than the nominal flow rate, the bigger the area of the reflux hole, the larger leakage that flow from the volute to liquid storage chamber. If the position of the reflux hole is closer to the tongue, the pressure difference between the volute and the liquid storage chamber is bigger. So the leakage flow from the volute into liquid storage through reflux hole is larger.