Experimental Study on Airlift Performance Reinforced by Water Jet Nozzle
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摘要: 在钻孔水力开采过程中,井底对岩屑产生的压持效应易导致气力提升系统输送能力减弱。为此,采用与实际作业相近的槽内供砂方式并引入水射流喷嘴研究其影响系统性能曲线及临界工况点的机理及规律。结果表明:水射流喷嘴数量N=3时就可消除槽底压持效应,起到大幅提高颗粒质量流量与提升效率之目的,之后则随其增加又对气力提升性能影响甚微。水射流喷嘴分布的非均匀性过高与过低均不利于增强气力提升性能。此外,水射流喷嘴在气举头埋入砂层(即气举头底部至砂床表层距离HQG,L,但却导致输砂临界气量值QG,S及与之对应的临界水流表观速度JL,cri因压持效应得到解除而大幅减弱,而后则随N增加仅微量减小。实测值JL,cri在H=0与理论模型中临界水流速度的计算值uLcri极为接近,但随H加大两者差异升高。Abstract: In the process of borehole hydraulic jet mining, the effect of chip hold-down produced at the bottom of the well on debris easily leads to poor transport capacity of an airlift system. To solve this problem, a new particle feeding method similar to the real situation was proposed, and the water jet nozzles were introduced to investigate the airlift performance and its critical points. The results are found as follows:The chip hold-down could be eliminated in the case of N=3, in turn, this makes the mass flow rate of solids and lifting efficiency increase greatly and then have a slight variations with increasing N; The appropriate inhomogeneity of spatial distribution of the water jet nozzles are also given to promote the airlift performance. Moreover, the mass flow rate of solids and lifting efficiency are especially improved by using water jet nozzles in the case of HQG,L for conveying water. However, the critical air flow rate QG,S and the critical volumetric flux JL,cri corresponding to lifting river sand are significantly decreased due to the disappearance of chip hold-down and then have a slight decrease with the increase of N. The JL,cri is very close to the computational value of theoretical model uLcri when H=0. But as H rises, their differences increase gradually.
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Key words:
- water jet nozzle /
- airlift /
- mass flow rate of solids /
- efficiency /
- critical condition /
- experimental study
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[1] Weber M, Dedegil Y. Transport of solids according to the air-lift principle[C]//Proceedings of 4th International Conference on the Hydraulic Transport of Solids in Pipes. Alberta, Canada, 1976 [2] Kassab S Z, Kandil H A, Warda H A, et al. Experimental and analytical investigations of airlift pumps operating in three-phase flow[J]. Chemical Engineering Journal, 2007,131(1-3):273-281 [3] Esen I I. Experimental investigation of a rectangular airlift pump[J]. Advances in Civil Engineering, 2010:Article ID:789547 [4] Moisidis C T, Kastrinakis E G. Pressure behaviour in riser tube of a short airlift pump[J]. Journal of Hydraulic Research, 2010,48(1):65-73 [5] Yoon C H, Park Y C, Lee D K, et al. Numerical analysis of solid-liquid-air three-fluid transient flow for air lift system[C]//Proceedings of the 14th International Offshore and Polar Engineering Conference. Toulon, France, 2004:23-28 [6] Pougatch K, Salcudean M. Numerical modelling of deep sea air-lift[J]. Ocean Engineering, 2008,35(11-12):1173-1182 [7] Hanafizadeh P, Saidi M H, Karimi A, et al. Effect of bubble size and angle of tapering upriser pipe on the performance of airlift pumps[J]. Particulate Science and Technology, 2010,28(4):332-347 [8] Dhotre M T, Joshi J B. Design of a gas distributor:Three-Dimensional CFD simulation of a coupled system consisting of a gas chamber and a bubble column[J]. Chemical Engineering Journal, 2007,125(3):149-163 [9] Hanafizadeh P, Ghanbarzadeh S, Saidi M H. Visual technique for detection of gas-liquid two-phase flow regime in the airlift pump[J]. Journal of Petroleum Science and Engineering, 2011,75(3-4):327-335 [10] Xia B R, Zeng X P, Mao Z X. Research on one borehole hydraulic coal mining system[J]. Earth Science Frontiers, 2008,15(4):222-226 [11] Cho N C, Hwang I J, Lee C M, et al. An experimental study on the airlift pump with air jet nozzle and booster pump[J]. Journal of Environmental Sciences, 2009,21 Suppl 1:S19-S23 [12] Ahmed W H, Badr H M. Dual-injection airlift pumps:an enhanced performance[J]. Particulate Science and Technology, 2012,30(6):497-516 [13] Hu D, Tang C L, Cai S P, et al. The effect of air injection method on the airlift pump performance[J]. Journal of Fluids Engineering, 2012,134(11):111302 [14] Tang C L, Hu D, Zhang F H. Effect of air injector on the airlift performance in air-water-solid three-phase flow[J]. Journal of Energy Engineering, 2014,140(1):04013006 [15] Tang C L, Hu D, Pei J H, et al. Effect of air injector on the performance of an air-lift for conveying river sand[J]. Chinese Journal of Mechanical Engineering, 2010,23(1):122-128 [16] Fujimoto H, Murakami S, Omura A, et al. Effect of local pipe bends on pump performance of a small air-lift system in transporting solid particles[J]. International Journal of Heat and Fluid Flow, 2004,25(6):996-100
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