Experimental Study of Vibration Characteristics Under Multiple Operating Conditions of the Pump as Turbine in Energy Micro-Grids

Centrifugal pumps as turbines (PATs) are key components in energy micro-grids, playing a significant role in energy conversion and storage. However, vibration and pressure pulsation occur during their operation, impacting the operational stability of the system. To investigate the complex relationship between PAT vibrations, pressure pulsations, and performance characteristics, specialized experiments were conducted in the precision laboratory of the National Research Centre of Pumps in Jiangsu University to gather the vibration data, pressure pulsations, and overall performance parameters of a PAT under varying operating conditions. The resulting data were then analyzed in both the time and frequency domains. The final results indicate that under both pump and turbine operating conditions, the vibration intensity increases with the increase in the flow rate. The vibration energy is predominantly concentrated at fBEP (blade passing frequency) and its harmonics, while the pressure pulsation intensity is the most significant at fn (the shaft frequency), fBEP, and the latter’s harmonics. This study is highly significant for optimizing pump design, enhancing pump performance, and ensuring the safe and stable operation of PAT systems.