Slug-flow horizontal

Heywood, N. I. and Richardson, J. F. Chem. Eng. Sci. 34 (1979) 17-30. Slug flow of air-water mixtures in a horizontal pipe determination of liquid holdup by y-ray absorption. 

Plug flow. Plug in horizontal flow, as shown in Figure 3.16, consists of enlongated gas bubbles. Although the name is sometimes used interchangeably with slug flow, it is differentiable in horizontal flow by the shape of the gas cavity or the appearance of staircase hydraulic jumps at the tails of air pockets (Ruder and Hanratty, 1990). 

The frictional pressure gradient is obtained by different correlations described in following sections. In a horizontal flow, (dp/dz)elev = 0, it is an ideal case to perform experiments excluding the term of elevation pressure drop. Because of nonhomogeneity of the slug flow, the acceleration pressure gradient term is different from that shown above it is given in Section 3.5.2.2. 

Dukler, A. E., and M. G. Hubbard, 1975, A Model for Gas-Liquid Slug Flow in Horizontal and Near Horizontal Tubes, Ind. Eng Chem. Fundam. 14(4) 337. (3)... 

Jens, W. H., and P. A. Lottes, 1951, Analysis of Heat Transfer, Burnout, Pressure Drop, and Density Data for High Pressure Water, USAEC Rep. ANL-4627, Argonne Natl. Lab., Argonne, IL. (4) Jepson, W. P., and R. E. Taylor, 1993, Slug Flow and Its Transitions in Large-Diameter Horizontal Pipes, Int. J. Multiphase Flow 19(3) 410420. (3)... 

Wallis (1969) discusses slug flow in horizontal and inclined pipes. 

Some detailed analyses of the mechanics of vertical slug flow (N4, G8) and vertical annular flow (A2, Cl, C6, LI) have appeared in recent years, and give a clearer picture of the microscopic behavior in these patterns. In general, this type of analysis is yielding better results with many vertical flow patterns because of their radial symmetry, than with horizontal flow patterns. 

Wallis points out that, from continuity considerations and bubble dynamics, the cocurrent flow of uniformly dispersed bubbles as a discontinuous phase in a liquid can always be made to occur in any system and for any void volume. (This is not true for countercurrent flow.) Coalescence of bubbles may occur, of course, and if this coalescence is sufiiciently rapid, a developing type of flow is observed, usually from bubble to slug flow. Because of this behavior, the particular flow pattern observed in bubble flow is quite dependent on the previous history of the two-phase mixture. This would be true for both horizontal and vertical flow. 

This paper presents mathematical and experimental studies of solids deposition characteristics in the horizontal pipeline of a dense phase slug flow pneumatic conveying... 

To understand the mechanisms of solids slug flows, a two-dimensional coupled DEM/CFD numerical model was built to simulate the motion of a pre-formed slug (ca. 0.3 m long) in a 1 m long horizontal 50 mm bore pipe as shown in Fig. 1. The pipe was initially filled with a layer of particles, approximately 15 mm thick at the bottom. (The thickness of this stationary layer was determined based on experience from previous experiments and computer test runs). 

Wambsganss, M. W., Jendrzejczyk, J. A., and France, D. M. (1994) Determination and Characteristics of the Transition to Two-Phase Slug Flow in Small Horizontal Channels, Journal of Fluids Engineering,... 

Fig. 4.45 Flow patterns in a horizontal, unheated tube a bubble flow b plug flow c stratified flow d wavy flow e slug flow f annular flow g spray or drop flow...

The case of slug flow in horizontal pipes has been considered by Sun et al. [248]. Here the situation is complicated by circumferential drainage of the liquid film layer between the slugs. The effects of nucleate boiling were also taken into account in this model. 

Avoid slug flow. Avoid the use of inclined lines, use either vertical or horizontal. Two-phase flow over a packing is given in Section 6. 17, trickle bed reactors. 

Dukler, A.E., Hubbard, M.G. (1975). A model for gas-liquid slug flow in horizontal and near horizontal tubes. Journal of Industrial Engineering and Chemistry 14(4) 337-347. 

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