Gas-liquid two-phase flow in the axial clearance of liquid-ring pumps

Abstract

In this study, the leakage flow in the axial clearance of a 2BEA-203 liquid-ring pump has been modeled through numerical simulation using the renormalization group k - ∈ turbulence model and the multiphase volume of fluid method. Numerical results show that the axial leakage flow reduces the inlet vacuum and efficiency of the liquid-ring pump. The gas-liquid two-phase flow within the axial clearance region is completely separated. Several droplets are scattered outside the suction region, some of which flow back into the low-pressure suction region along the wall of the suction port. Given the axial asymmetry of the flow passage, the phase distribution within the impeller region is non-uniform along the axial direction. The numerically simulated pressure distribution within the axial clearance region accords well with the vortex distribution caused by the leakage flow. The leakage flow interacts with the impeller flow, and forms a corner vortex near the pressure side and a leakage vortex near the blade suction side. As the relative coordinate of the cross planes to the blade (sc−1) decreases from tip to hub, the corner vortex near the blade pressure side gradually weakens while the leakage vortex near the suction side gradually strengthens. These vortices mostly form in the suction and compression zones of the clearance region and significantly affect the overall pump efficiency. Findings of this study reveal the flow structure in the axial clearance of the liquid-ring pump and the interaction between the leakage and main flow.