Abstract: The pressure fluctuations in double-suction centrifugal pumps caused by internal flow are the primary sources of operation instability. In order to investigate the effects of impeller types on pressure fluctuations for double-suction centrifugal pumps, five impeller configurations are tested with the same experimental facilities. By arranging pressure transducers on the walls of suction chamber and spiral casing, fluctuating pressure signals are collected at various test flows. The signals in time domain are analyzed by using the FFT method and the frequencies are obtained. Results show that blade passing frequency, rotating frequency and some lower frequencies always exist in double-suction centrifugal pumps. Compared with the traditional impeller, the double suction impeller with bilateral blades staggered can reduce the level of pressure fluctuation. By adjusting the blade outlet shape and increasing the warp angle of the blade near the back shroud side, the amplitude of the pressure fluctuation at blade passing frequency becomes small. The impeller with splitter blades optimizes the flow state, lessens the pressure fluctuation in suction chamber region and improves the characteristic of pressure fluctuations in the spiral casing under small flow rate condition.

Key words: Double-suction centrifugal pump, Frequency spectrum analysis, Impeller type, Pressure fluctuation