Air-lift pumps characteristics under two-phase flow conditions

International Journal of Heat and Fluid Flow 01/2009; 30(1):88-98. DOI: 10.1016/j.ijheatfluidflow.2008.09.002

ABSTRACT Air-lift pumps are finding increasing use where pump reliability and low maintenance are required, where corrosive, abrasive, or radioactive fluids in nuclear applications must be handled and when a compressed air is readily available as a source of a renewable energy for water pumping applications. The objective of the present study is to evaluate the performance of a pump under predetermined operating conditions and to optimize the related parameters. For this purpose, an air-lift pump was designed and tested. Experiments were performed for nine submergence ratios, and three risers of different lengths with different air injection pressures. Moreover, the pump was tested under different two-phase flow patterns. A theoretical model is proposed in this study taking into account the flow patterns at the best efficiency range where the pump is operated. The present results showed that the pump capacity and efficiency are functions of the air mass flow rate, submergence ratio, and riser pipe length. The best efficiency range of the air-lift pumps operation was found to be in the slug and slug-churn flow regimes. The proposed model has been compared with experimental data and the most cited models available. The proposed model is in good agreement with experimental results and found to predict the liquid volumetric flux for different flow patterns including bubbly, slug and churn flow patterns.

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    ABSTRACT: Airlift pumps are devices which are widely used in industrial applications. Parameters such as diameter of the pipe, tapering angle of the upriser pipe, submergence ratio, the gas flow rate, bubble diameter, and inlet gas pressure affect the performance of this type of pumps. In this research, the performances of airlift pumps with a vertical upriser length of 914 mm and initial diameters of 6 and 8 mm and various heights for steps, range 0.2 to 0.9 m, in submergence ratio of 0.6 are investigated numerically. The results show the improvement in the performance of step airlift pump (SALP) in comparison with ordinary type (OALP). Considering the effect of height of steps and secondary pipe diameter, can be shown that in constant gas flow rate there exist specific height and secondary diameter for step which can optimize the performance of the pump. The numerical results were compared with the existing experimental data, showing a reasonable agreement. The results have indicated that step airlift pump has higher efficiency than the pump with constant pipe diameter.
    International Journal of Fluid Mechanics Research 01/2011; 38(5):387-408.
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    ABSTRACT: The present study investigates a hierarchy of models for predicting the performance of air-lift pumps. Investigated models range from simplified one-dimensional analytical models to large eddy simulation (LES). Numerical results from LES and from two differ-ent analytical models are validated against experimental data available from the air-lift pump research program at Alexandria University. Present LES employs the volume of fluid (VOF) method to model the multiphase flow in the riser pipe. In general, LES is shown to provide fairly accurate predictions for the air-lift pump performance. Moreover, numerical flow patterns in the riser pipe are in good qualitative and quantitative agree-ment with their corresponding experimental patterns and with flow pattern maps avail-able in the literature. On the other hand, analytical models are shown to provide results that are of surprisingly comparable accuracy to LES in terms of predicting the pump per-formance curve. However, due to the steady one-dimensional nature of these models, they are incapable of providing information about the different flow patterns developing in the riser pipe and the transient nature of the pumping process. [DOI: 10.1115/1.4027473]
    Journal of Fluids Engineering 11/2014; 136(11):111301. · 0.89 Impact Factor
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    ABSTRACT: An airlift pump can be used to pump liquids and sediments within itself, which cannot easily be pumped up by a conventional method, by using the airlift effect. This characteristic of the airlift pump can be exploited in a DCFC (Direct Carbon Fuel Cell) so that molten fuel with high temperature may be carried or transported. The basic characteristics of airlift are investigated. A simple system is constructed, where the reservoir is filled with water, a tube is inserted, and air is supplied from the bottom of the tube. Then, water is lifted and its flow rate is measured. Bubble patterns in the tube are observed in a range of air flow rates with the parameters of the tube diameter and submergence ratio, leading to four distinct regimes. The pumping performance is predicted, and the correlation between the supplied gas flow rate and the induced flow rate of water is found.
    Transactions of the Korean Society of Mechanical Engineers B 01/2013; 37(9).


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Jun 6, 2014