Dynamic evolution of the gas–liquid interface and gas blockage mechanism in rotating channels of a multistage electric submersible pump

Under high gas volume fraction conditions, gas blockage in the rotating channel of electric submersible pumps (ESPs) can lead to severe performance deterioration or even failure. This paper presents a numerical study focusing on the dynamic evolution of the gas–liquid interface and the gas blockage mechanism in a rotating channel, mimicking the internal flow of an ESP. A computational fluid dynamics method coupling the population balance model and the ideal gas model is employed. Compared to previous studies, the average error of the simulations with experimental results in this research has been reduced from 25.6% to 8.2%. Based on this, this paper deeply explores the regulatory effects of the operating parameters of a three-stage ESP on the two-phase flow structure and the gas phase distribution characteristics. The results show that increasing the inlet gas volume fraction enhances backflow at the impeller outlet, widening the gas–liquid velocity gap. Gas buildup in the impeller–diffuser transition zone blocks the flow, sharply raising resistance and reducing stability. This paper further studies the distribution law of bubble sizes within the three sets of impellers and establishes and verifies an equivalent bubble size prediction model suitable for different stage impellers.