Analysis of Internal Flow and Pressure Pulsation Characteristics in a Series-Connected Double-Suction Centrifugal Pump System

抄録

To investigate the internal flow, pressure pulsation characteristics, and the interaction between the front and rear pumps of double-suction centrifugal pumps in series, a system consisting of two identical double-suction centrifugal pumps connected in series was studied. Based on Ansys CFX commercial software, the SST k-ω turbulence model was used to carry out the numerical simulation of the whole flow channel. The result indicates that two identical double-suction pumps operating in tandem exhibit optimal flow matching at the design flow rate (1.0Q_d). The pressure distribution shows a gradual increase along the flow path, while the volute tongue experiences the most severe static and dynamic interferences. Under off-design flow conditions (0.8Q_d and 1.2Q_d), the monitoring point at the volute tongue experiences significantly amplified pressure pulsations with amplitudes 8-10 times greater than design conditions. Pressure pulsations in the rear impeller demonstrate distinct pulsation signals at blade passing frequency (BPF) harmonics, whereas the front impeller is predominantly concentrated in the low-frequency band (0.2-0.4BPF). On the suction surface of the rear impeller, pressure pulsation amplitude exhibits periodic growth with increasing flow rate.