バブルジェット式エアリフトポンプによる堆積土砂の浚渫（改良型装置の実験と性能予測）

抄録

The bubble-jet-type air-lift-pump developed by Sadatomi can dredge sediments hardly deposited on lake and sea beds by striking water jet with small bubbles against them and causing air-lift force on gas-liquid-solid mixture in the riser of the pump. In order to make the pump efficient even in deep-water zones, the pump was revised in our previous study. In the present study, results of additional experiments and performance predictions on the revised one of laboratory size are reported. In the experiment, 26 mm I.D. riser and a new 50 mm I.D. riser, each 5.0 m in length, and four kinds of solid particles of different size and density were used. Air supply rate was varied systematically at three submergence ratios from 0.76 to 0.84. The experimental results on the revised system has better particle discharge rate than the original system under the same power consumption condition. In the performance prediction, Yoshinaga et al.'s model was modified for the present purpose because their model is applicable only to a usual air-lift-pump. In addition, a new correlation of flow rate ratio of particles was derived based on the present data, and the new correlation was included in the model. As a result, the particle discharge rate at any air supply rate could be well predicted.