A slugh-churn flow model for small-diameter airlift pumps

Abstract In an airlift pumping process, air is injected into the pipe containing the fluid to be transferred. Small-diameter airlift pumps are in particular used for corrosive or radioactive liquids. Detailed experiments including differential pressure and void fraction measurements, are carried out on a 10 mm-diameter setup. Based on the results obtained, it is shown that existing models are not appropriate for small diameter airlifts, particularly because they overpredict the frictional pressure drop in slug flow. A new steady state airlift model is proposed. The pressure gradient in the riser is predicted by a combination of specific models describing slug and churn flow. These models are based on the available literature on two-phase flow. The particular structure of slug flow is accounted for by a cellular model. The model proposed represents an accurate analysis tool for the design of small diameter (up to 40 mm), tall (length-to-diameter ratio greater than 250) airlifts.

[1]  Nigel N. Clark,et al.  A general design equation for air lift pumps operating in slug flow , 1986 .

[2]  D. J. Reinemann,et al.  Theory of small-diameter airlift pumps , 1990 .

[3]  Geoffrey F. Hewitt,et al.  Prediction of the slug-to-churn flow transition in vertical two-phase flow , 1992 .

[4]  Ovadia Shoham,et al.  Gas-liquid flow in inclined tubes: Flow pattern transitions for upward flow , 1985 .

[5]  N. Zuber,et al.  Average volumetric concentration in two-phase flow systems , 1965 .

[6]  E. T. White,et al.  The velocity of rise of single cylindrical air bubbles through liquids contained in vertical tubes , 1962 .

[7]  Neima Brauner,et al.  Slug/churn transition in upward gas-liquid flow , 1986 .

[8]  N.C.J. Ros,et al.  Simultaneous Flow of Gas and Liquid As Encountered in Well Tubing , 1961 .

[9]  O. G. Martynenko,et al.  Handbook of hydraulic resistance , 1986 .

[10]  Y. Sato,et al.  Performance of Air-Lift Pump , 1972 .

[11]  D. Kouremenos,et al.  Performance of a small air-lift pump , 1985 .

[12]  R. R. Rothfus,et al.  Turbulent liquid flow down vertical walls , 1959 .

[13]  R. Lockhart.  Proposed Correlation of Data for Isothermal Two-Phase, Two-Component Flow in Pipes , 1949 .

[14]  G. Hewitt,et al.  Annular two-phase flow , 1970 .

[15]  D. Barnea.  Effect of bubble shape on pressure drop calculations in vertical slug flow , 1990 .

[16]  V. Nakoryakov,et al.  Experimental study of gas-liquid slug flow in a small-diameter vertical pipe , 1986 .

[17]  G. Wallis.  One Dimensional Two-Phase Flow , 1969 .

[18]  A. Dukler,et al.  Hydrodynamic model for gas‐liquid slug flow in vertical tubes , 1983 .

[19]  Geoffrey F. Hewitt,et al.  Flooding and churn flow in vertical pipes , 1991 .

[20]  A. E. Dukler,et al.  Modelling flow pattern transitions for steady upward gas‐liquid flow in vertical tubes , 1980 .