Prediction of back-pressure induced stall in eductor-jet pumps

Eductor-Jet pumps are used to transfer large quantities of fluids using another high-pressure fluid source and the Venturi effect. These pumps can be alternatives to motor driven pumps when no electricity is available or use of electricity is hazardous. When an eductor-jet pump is used to inflate a closed inflatable, like an airbag, it stalls as the pressure increases within the bag. In this paper, critical stall condition at which the stall occurs is investigated by comparing thrust force from the jets of pump to the force due to the backpressure in the inflatable. Steady-state CFD analyses were performed for various jet inlet pressures and backpressure conditions using a typical eductor-jet pump geometry. 3D Computational Fluid Dynamics simulations show that the velocity profiles and experiments with a 3D-printed pump were used to verify the developed force comparison method are very effective in stall prediction.