Effect of baffles on internal flow characteristics of double-inhalation centrifugal pumps under low flow conditions

In order to investigate the impact of baffles in the inhalation chamber on the external characteristics and operational stability of a double inhalation centrifugal pump under low flow conditions, the flow field simulation software ANSYS CFX and the shear stress transport formulation were employed to numerically simulate the internal flow field of a double inhalation centrifugal pump with and without baffles. Two models were subjected to performance curve simulation and prediction, with the internal flow field, pressure pulsation, and impeller force of the two models being compared and analyzed under three small flow conditions of 0.6Qd (rated flow), 0.5Qd, and 0.4Qd. The velocity and vortex distribution inside the semi-spiral inhalation chamber, as well as their impact on the flow state in front of and inside the impeller, were analyzed. Research has demonstrated that the addition of baffles can enhance the pump head and efficiency in flow conditions of 0.5Qd–0.8Qd. However, there is a tendency for obstruction of flow in conditions below 0.5Qd. Baffles can reduce the amplitude of pressure pulsation within the impeller and the radial force exerted by the impeller as a whole. Consequently, the incorporation of baffles within the inhalation chamber during flow conditions of 0.5Qd–0.8Qd can enhance the operational efficacy of the pump. Nevertheless, within the flow range of <0.5Qd, the pump's performance will decline. This study serves as a foundation for the design of double inhalation centrifugal pumps with semi-spiral inhalation chambers.