Numerical Investigation of the Transient Flow and Frequency Characteristic in a Centrifugal Pump with Splitter Blades

To analyze the internal flow characteristics of each subchannel in a low-specific-speed centrifugal pump with splitter blades, the time histories and frequency spectra of pressure fluctuations and the distributions of the corresponding flow states in one impeller channel were investigated through the numerical analysis. Performance experiments and particle image velocimetry (PIV) tests were carried out to verify the results of the numerical calculations. The results suggested that the simulation analysis agreed well with the test results. The time histories and frequency spectra of pressure fluctuations depending on its location (close to or away from the volute tongue) present different changes. The predominant frequency of each monitor point equals to five or ten times shaft frequency. The jet-wake flow pattern at each subchannel separated by splitter blade in one impeller channel is not circumferentially uniform. For the channel away from volute tongue, the magnitude of turbulence kinetic energy in pressure side subchannel is well larger than that in suction side subchannel. With the increase in flow rate, the region close to the elbow of the volute outlet emerges a large-scale vortex.