Research on bubble trajectory and flow structure in helical-axial multiphase pump

The oil-gas two-phase hybrid transportation technology is one of the innovative technology directions for the exploitation and transportation of marginal and deep ocean oilfields. The helical-axial multiphase pump is a key equipment for oil and gas extraction. At this stage, most of the research on this kind of pump focuses on the improvement of the structure and conveying performance. However, because of insufficient understanding of the flow behavior and mechanism of bubbles, it is easy to cause the gas-liquid separation. In this paper, the numerical simulation and test are combined to explore the changes in the bubble trajectory and flow structure of the helical-axial multiphase pump. The results shown that when the speed is lower than 1 200 r/min, the bubble reaches the maximum volume at 1/2 of the midline of the impeller blade and it contact with the pressure surface, broken to the suction surface. When the rotation speed is higher than 1 450 r/min, the number of bubbles in the impeller increases and the size decreases. The backflow occurs in the tip clearance and strength increases continuously. The research results have important significance for the theoretical design and engineering application of the helical-axial multiphase pump.