Experimental study on the dredging performance of the externally excited oscillating airlift pump

Abstract

Due to the increase of sediment carried by the upstream with years, sediment deposition and hardening gradually aggravated, which has severe impact on the waterway passage and agricultural irrigation. Therefore, to develop a highly efficient dredging device is urgently needed. An externally excited oscillating airlift pump is proposed to improve the dredging performance of the existing ring-jet airlift pump, and the influence of excitation methods and working conditions is analyzed. The findings show that under different excitation methods, both water and sand discharge show a reciprocal oscillating pattern as the duty cycle increases, and the overall trend is decreasing. When the duty cycle is 50% and 30% respectively, both water and sand discharge reach their maximums; the corresponding sand discharge in horizontal operation performs better than that in descent operation, and in either operation mode, the externally excited oscillating airlift pump exhibits better discharge performance of solids than the continuous air intake. In the untimed continuous suspended pumping, its sand discharge capacity and disturbance range on the silt layer are greater than the continuous airlift pump. At the duty cycle of 30% and the frequency of 0.4 Hz, its discharge performance and disturbance effect on the bottom silt layer work best.