The Theoretical Analysis And Experimental Study On An Air-lift Device

The air-lift in vertical pipes is frequently encountered in deep-seamining, hydraulic coal-mining and river sludge removing. However duringthe deep-sea mining, the minerals have to be transported to earth surfacefrom the ocean bed under the water several thousands meters, withincreasing serious energy shortage, the research on this topic has beenimminent. In addition, most rivers have serious mud filling, the cloggingoccurs from time to time, some of the water has been seriously weakenedin flood control. How to remove the large amount of sediment deposition inthe bed river is urged to be solved up.In light of it, The imagination of using air-lift for dredging anddeep-sea mining was proposed in this dissertation, the small air-lift systemis established in the laboratory, the river sands, which have a density of2050 kg /m3 are used as the test particles, the diameter of materials are1 ? 3mm . Air-lift performance was investigated experimentally for differentparameters.First, this dissertation introduces the principle of the air-lift, theinfluencing factors on the friction loss and efficiency are classified, thecreation and calculation method of which are analyzed gradually.Meanwhile, the models which describe the friction loss and efficiency inthe upriser are proposed based on Bernoulli's equation, momentumequation and energy equation.Secondly, on the basis of research results of the previousinvestigators and practical laboratory situation, the air-lift apparatus isdesigned, the innovative design on the air injection installment and thetesting device have been carried out, the whole experimental set-up hasalso been processed successfully. It shows that the experimental set-up,which has advantage of apparent lifting phenomenon and convenient test,conforms to the anticipated tentative presumption.Finally, air-lift performance (It contains mass flow of dischargedparticles, volume of discharged water, concentration of particles andefficiency) was investigated experimentally for different parameters, which mainly contain submergence ratios, air flow rate, types of air injectors, jet nozzles and the distance between the bottom of riser pipe and sand bed, the performance results can be obtained according to large number of experimental dates judging by different experimental program. The experimental results shows a marked effect on the pump performance when operated with different structure parameters, it is found that there is a suitable air injection method for optimal promotion effect,In conclusion, the research on this academic provides theory method for river sludge removing and deep-sea mining,the obtained experiment result can be referred as engineering application.