Abstract:To study the internal flow behaviors in the self-priming process of self-priming pump, the gas-liquid two-phase steady numerical simulation was carried out based on an external mixing self-priming centrifugal pump. The gas-liquid two-phase distribution and average static pressure distribution of impeller and volute under different inlet gas content were analyzed. It provides a basis for the optimal design of self-priming pump. The results show that the gas phase first accumulates at the back of the blade and the tongue area near the impeller inlet. With the increase of the inlet gas content, the gas phase gradually diffuses into the impeller and volute channel, which is not conducive to the transportation of two-phase flow, and affects the self-priming performance of the pump. The gas content in the circumferential and axial plane of the impeller is similar to that in the inlet, but the gas content in the axial plane of the volute is quite different from that in the inlet. The low pressure area in the impeller and the volute decreases gradually with the increase of gas content, but the average static pressure value increases gradually. With the increase of relative height and the decrease of inlet gas content, the average pressure in the axial plane of the impeller decreases obviously, while the average pressure in the axial plane in the volute decreases first and then increases. When the gas content exceeds 10%, the head decreases obviously, and the hydraulic performance of the pump is greatly affec-ted by the inlet gas content.