Performance optimization of centrifugal pumps: Experimental analysis of flow enhancement and cavitation mitigation under variable operating conditions

Cavitation is critical in centrifugal pumps, leading to performance degradation, energy loss, and mechanical damage. This study presents an experimental approach for early detection and proactive management of cavitation by analyzing vibration signals and controlling fluid flow parameters. A comprehensive test rig was developed, comprising a centrifugal pump with a transparent casing, a variable-speed motor, and a computerized vibration monitoring system equipped with high-accuracy piezoelectric sensors and digital data acquisition. The primary objective is to identify the critical suction valve angle and operating parameters at which cavitation begins, using a combination of visual observation, vibration signal, envelope analysis, and theoretical evaluation. The simulation of a blockage in the system that could cause cavitation through three main test stages was examined and analyzed experimentally and theoretically. Stage 1 (3002 rpm, 0° valve angle): stable operation with a flow rate of 19.8 L/min and vibration peak at 0.2098 m/s², showing no cavitation. Stage 2 (3003 rpm, 22.5° valve angle): early-stage cavitation identified with a reduced flow rate of 14.8 L/min, high-frequency peaks at 1445.3 Hz (0.4264 m/s²) and 1806.0 Hz (0.2106 m/s²), and a damage index of 2.5 in envelope analysis. Stage 3 (2196 rpm, 22.5° valve angle): cavitation was successfully mitigated at a lower flow rate of 10.75 L/min, where high-frequency noise was eliminated, and the damage index dropped below 0.2.