Quantitative characterization of liquid pump pulsations via velocity profiling and a volumetric prover

Abstract This study presents a novel system for quantitatively characterizing pulsations in liquid pumps, combining a controllable volumetric prover with velocity profiling techniques; e.g. particle tracking velocimetry (PTV). The system extracts the pulsating flow component contained in the flow rate from a target pump. In this study, our PTV system is capable of measuring pulsation flow rate as low as 0.1 l h −1 . The efficacy of the measurement system was verified using an overflow head tank as a representative flow supplier generating a stable flow rate. The pulsation frequencies and amplitude ratios were analyzed through Fourier transforms, enabling the identification of characteristic pulsations in the flow rate. As a novel indicator of pulsation characteristics, an evaluation method with local peak detection and statistical analysis was proposed to characterize pulsations quantitatively. Two representative pumps were tested: results showed that the rotary lobe pump exhibited variable pulsation ratios up to approximately 20% as the flow rate changed, while the diaphragm pump indicated more stable pulsation ratios, lower than 5%. Although the diaphragm pump generally suppresses overall pulsations more effectively than the rotary lobe pump, it exhibited more pronounced local pulsation peaks under specific operating conditions, such as low-flow or startup phases. The proposed method can clarify the pulsation characteristics, not only amplitude spectra but also detailed pulsation waveforms, which will help identify the damping frequency required to suppress pulsation and develop further ‘pulsation-free’ pumps.