| The air-lift technology has been applied in the field of underground mining, deep-well watering, oil drilling, deep-sea mining and river sludge removing etc. But air-injection method of air-lift equipment is seldom studied at home and abroad. The subject adopts experimental method. The effect of air-injecting method on air lifting performance is studied by changing the numbers of airflow nozzle, the arrangements of airflow nozzle and the airflow injecting angle to find the corresponding air-injection method combinations at the optimal conditions.This dissertation introduces the principle of the air-lift, the influencing factors on the friction loss are analyed. The model of efficiency has been established .The existing hydraulic system has been improved. A small air-lift system is established and two air injecting equipments are designed in the laboratory. the river sands, which have a density of 2050 kg/m~3 are used as the test particles, the average diameter of materials is 3mm. The effect of the air-lifting performance is studied on the different air-inecting methods.Two gas injectors of circular gas cavity and square gas cavity are designed. The effect of air-injecting methods on air lifting performance is studied by changing the numbers of airflow nozzle, the arrangements of airflow nozzle and the airflow injecting angle to test the volume of discharged liquid, the mass of discharged sand and concentration of paticles from the outlet of air-lifting pipe as well as lifting efficiency. The experimental results show that the volume of discharged water and lifting efficiency are highest in the certain of airflow rate when three airflow nozzles were adopted and the mass of discharged sand as well as concentration of particles from th outlet of air-lifting pipe are best in the certain of air flow rate when six airflow nozzles of the circular gas cavity were used. For the four arrangements of six airflow nozzles, we find that the volume of discharged liquid, the mass of discharged sand and the air lifting efficiency are best when used the arrangement of three holes on the diameter, a hole on one side and two holes on the other sides. But the effect of the numbers of airflow nozzle on the volume of discharged water, the mass of discharged sand, the concentration of particles and the lifting efficiency are not marked when the square air cavity was adopted. In the different airflow nozzle angles, the volume of discharged water and the air-lifting efficiency are highest whenα=90°was adopted, the mass of discharged sand is weightest whenα=17°was used and the concentration of particles is best when make use of theα=64°.The research on this academic provides practical application for underground mining, deep-well watering, deep-sea mining and river sludge removing. It has important meaning for the river and port's underground minerals removing, underground minerals mining and the ocean resources developing. |
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