Study on the unsteady flow characteristics of gas unblocking in multiphase pumps

Multiphase pumps are critical for oil and gas transportation, but gas blocking can increase backpressure, reduce efficiency, and in severe cases, lead to failure in transporting multiphase media. In this study, a gas unblocking model was established based on dynamic mesh technology, and validated through both laboratory and field experiments to analyze the internal flow characteristics during gas blocking and unblocking processes. The results show that increasing pressure reduces vortex formation, alleviating gas blocking, while incoming liquid effectively dissipates vortices, resolving the blockage. Throughout the unblocking process, the impact of velocity, turbulent kinetic energy, and flow noise shifts from the inlet to the outlet, with reduced velocity fluctuations and decreased energy loss. Noise levels range from 40 dB to 120 dB, with the highest sources of noise and leakage occurring at gaps delta and e. There are consistently four separation points on the rotor, and leakage at gap delta can be partially mitigated at these points. These findings offer theoretical guidance for the design and application of gas unblocking in multiphase rotor pumps.