Centrifugal pump is extensively used in wastewater, pulp, and biomass industries for transporting of particle flows. The motion and distribution of flexible particles are critical for continuous and stable pumping. In this work, a test rig is set up for straw particle flow pumping. A stroboscopic flash is employed to capture the distribution of the straw particle. The pump performance is measured and compared to that of clear water. By increasing the particle concentration, the process from stable pumping to eventually clogging is observed. Firstly, in a wide operation range with 0.1% concentration, the particle is uniformly distributed in the flow passage and the pump is running in a hydrodynamic stable mode where the power increases gradually and is slightly over the pure water circumstance. However, the high efficiency region is shifted to lower flow rate and it becomes narrower as compared to the pure water case. Secondly, at 0.2% and 0.4% concentration, the performance resembles the 0.1% case. But with increasing concentration, the inception of small flocs is observed. In addition, small air bubble is formed near the rotating axis. This subtle change continues until clogging happens. By gradually increasing the concentration of particle, more and more particles are attached to the growing flocs. Finally, the pump runs into mechanical wear between particles and flow passage, and then it is fully clogged. In this condition, the power consumption increases rapidly and the variable frequency drive is used to bring down the shaft speed. The long-term running shows relatively light erosive wear on the surface of impeller and volute by the particles, but no damage is observed.

中文翻译：

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离心泵中秸秆颗粒流动的实验研究

离心泵广泛用于废水、纸浆和生物质行业，用于输送颗粒流。柔性颗粒的运动和分布对于连续稳定的泵送至关重要。在这项工作中，设置了一个用于秸秆颗粒流泵送的试验台。使用频闪来捕捉秸秆颗粒的分布。测量泵的性能并与清水的性能进行比较。通过增加颗粒浓度，观察到从稳定泵送到最终堵塞的过程。首先，在0.1%浓度的宽运行范围内，颗粒均匀分布在流道中，泵以水动力稳定模式运行，功率逐渐增加，略高于纯水环境。然而，与纯水情况相比，高效率区域转移到较低的流量并且变得更窄。其次，在 0.2% 和 0.4% 的浓度下，性能类似于 0.1% 的情况。但随着浓度的增加，观察到小絮凝物的出现。此外，在旋转轴附近会形成小气泡。这种微妙的变化一直持续到发生堵塞。通过逐渐增加颗粒浓度，越来越多的颗粒附着在生长的絮状物上。最后，泵在颗粒和流道之间发生机械磨损，然后完全堵塞。在这种情况下，功率消耗迅速增加，并使用变频驱动器降低轴速。