Abstract
The bubble-jet-type air-lift pump was invented by Sadatomi in order to pump up water and sediments deposited on lake and sea beds by striking water jet with air bubbles. In the present paper, the performance of the pump has been reported. In the experiments, the upriser of the pump was 50 mm I.D. and 5.0 m long. The test sediments were three kinds of spherical particles of different size and density, while the test liquid was 3.0 wt % saltwater in view of the usage in sea. The submergence ratio of the upriser in the water was changed from 0.76 to 0.84, and the air supply rate to the upriser was changed up to 250 l/min while the water rate to the bubble-jet-generator was fixed at 72.0 l/min. In the analysis, Yoshinaga et al.’s model for predicting water and particles discharge rates was modified by incorporating a new correlation of particles flow rate fraction in water-particles mixture. The modified model could predict well the present data as well as our previous data at an efficient pump operation condition irrespective of the differences in the salinity, the particles specifications and the submergence ratio.
