Experimental measurement of particle flow and energy performance in a centrifugal pump

Pumps are among the most critical equipment in deep-sea mining, and the transported mineral particles directly influence pump performance and operational longevity. To investigate the particle motion mechanism and its influence on pump performance, high-speed photographic visualization experiments were conducted to analyze the effect of the Particle Reynolds number (Re_t) on particle dynamics within the pump. The results reveal that at low Re_t values, particles are randomly distributed within the pump. However, as Re_t increases, particles gradually migrate towards the blade pressure surface and deposit on the volute wall. Particles enter the impeller at divergent angles, collide with the blades, and ultimately accumulate near the blade trailing edges after stabilization. After entering the impeller, the radial distance from the rotation center to particle impact points on the blades decreases with impeller rotation. Absolute trajectory analysis indicates that larger particles traverse the impeller faster, whereas relative trajectory analysis reveals their tendency to concentrate near the blade pressure surface. At low Re_t, the head exhibits a slight increasing trend. As Re_t and particle volume fraction increase, the head gradually declines. Based on comprehensive experimental data, a head reduction equation incorporating median particle size, density, and volume fraction was developed and validated. These findings elucidate particle motion mechanisms and offer theoretical insights for designing solid-liquid two-phase flow pumps.