Abstract：In order to study the basic law of the internal flow and external characteristics of the centri-fugal pump under the condition of gas-liquid mixed transportation. The direct-coupled single-stage and single-suction centrifugal pump with a specific speed of ns=132.2 was selected. Based on the dimensionless analysis method, the external characteristics tests and numerical simulation under the condition of different rotational speeds and different inlet gas volume fractions were carried out. The results show that the dimensionless parameters of pressure coefficient and velocity coefficient can directly reflect the basic internal flow of gas-liquid two-phase flow in centrifugal pump. With the increase of the rotating speed, the radius of the low-pressure area around the impeller inlet increases gradually, and the area of the low velocity occupying the flow passage also increases gradually. At this time, the gas mainly concentrated near the impeller flow passage and the volute, which is easy to block the flow passage, and the energy between the liquid phase and the impeller cannot be effectively exchanged and transferred, which is the main reason that the external centrifugal pump characteristics curve no longer follows the similarity law when the inlet gas volume fraction is more than 3% at the condition of gas-liquid mixed transportation. Combined with the experimental and numerical simulation results, the rationality of the Eulerian-Eulerian inhomogeneous model is verified, which provides a theoretical basis for the optimal design of the pump.
