Effects of Back Pressure on Flow Regime and Suction Performance of Gas-Liquid Swirl Ejector

The back pressure of a gas-liquid swirl ejector is a critical parameter that affects the flow regime and entrainment performance of the system. In the case of a weak swirl injection, the motive jet carries relatively higher axial momentum thus remains in a single phase and the liquids appear glassy. With increasing in the back pressure of the bubble flow, the suction rate drops rapidly. For a strong swirl injection, the liquid jet is disintegrated due to higher angular momentum and the spray is atomized. Augmentation in the back pressure also causes the reduction in the suction rate but it tends to grow more gradual than the weak swirl injection. As a result, the suction rate of the strong swirl is greater than that of the weak swirl in the majority of the back-pressure range. However, owing to the high transition pressure, only the weak swirl entrains the air in the bubble flow regime at low back pressure. The relationship between the suction and the swirl intensity is not fixed and is influenced by the back pressure.