Abstract：In order to study internal flow patterns and thrust on an impeller under gas-liquid two-phase flow conditions, a centrifugal pump with a specific speed of 129 is selected, and the unsteady three-dimensional flow in th pump is simulated by employing the Eulerian-Eulerian inhomogeneous multiphase flow model based on ANSYS CFX software. The variations of a few fluid flow variables such as pressure loading on blades, gas volume fraction distribution etc are obtained under different gas volume fractions admitted at the pump inlet, the predted head and efficiency are compared with the measured data. The results show that the gas phase is mainly accumlated on the blade suction surface and in the middle part of flow passage at the impeller outlet, further the gas volume fraction on the shroud are higher than on the hub. With increasing gas volume fraction at the pump inlet the flow disortion in the impeller passages becomes severe, henece the flow inhomogeneity between the gas phase and the liquid phase is intensified, and the vortex area is enlarged. From the inlet to the outlet of impeller, the pressure loading on the blade pressure surface reduces faster than on the blade suction surface, but the loading on the suction surface declines quicker near the impeller outle. The imbalance of the radial thurst on the impeller gets worse, and the torque acted on it decreases.
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