Bubbling-slugging transition

Figure 38. Bubbling-slugging transition evaluation for two different solid-to-gas density ratios.

The downhill and horizontal bubble-slug transition equation is... 

Figure 3.21 is a plot of bubble-to-slug transition lines for various test pressures ... 

Figure 3.21 Bubble-to-slug transition lines for various test pressures. (From Hosier, 1968. Copyright 1968 by American Institute of Chemical Engineers, New York. Reprinted with permission.)...

Superficial gas velocity where the transition from bubbling/ slugging to turbulent fluidization begins... 

Superficial gas velocity where transition region from bubbling/slugging to turbulent fluidization ends... 

Suo and Griffith (1964) performed experiments in horizontal channels with 0.5 and 0.7 mm diameters, and could identify slug, slug-bubbly, and annular flow patterns. For transition from slug to slug-bubbly, they suggest ReWe = 2.8 x 10, where Re = We = dpildljla, = 1. 2(Gls + 1/gs)- Re and We rep-... 

Figure 5.16c indicates that as the channel size was reduced to Jh = 0.866 mm, the dispersed bubbly flow pattern vanished from the flow regime map. Figure 5.16a-c indicates that the slug-churn flow transition line shifted to the right, as the channel size was reduced. Similar trends were also found in small circular tubes by the... 

Figure 5.6 Flow pattern map for a gas/liquid flow regime in micro channels. Annular flow wavy annular flow (WA) wavy annular-dry flow (WAD) slug flow bubbly flow annular-dry flow (AD). Transition lines for nitrogen/acetonitrile flows in a triangular channel (224 pm) (solid line). Transition lines for air/water flows in triangular channels (1.097 mm) (dashed lines). Region 2 presents flow conditions in the dual-channel reactor ( ), with the acetonitrile/nitrogen system between the limits of channeling (I) and partially dried walls (III). Flow conditions in rectangular channels for a 32-channel reactor (150 pm) (T) and singlechannel reactor (500 pm) (A) [13].

Pattern transition in vertical adiabatic flow. Upward vertical flow has been studied intensively, both because of the simplicity of the geometric condition and the relevance in applications. The map shown in Figure 3.4 is the result of rather recent and relevant studies into the interpretation of regime transition mechanisms. In this figure, the transition between bubbly flow and slug flow occurs be-... 

The basic mechanism for transition from bubble to slug flow appears to be the same as in vertical pipe flow. That is, as the gas flow rate is increased for a given liquid flow rate, the bubble density increases, many collisions occur and cell-type Taylor bubbles are formed, and the transition to slug flow takes place. As shown in the case of vertical pipe upflow, Taitel et al. (1980) assumed that this transition takes place when ac = 0.25. This criterion is also applicable here. However, because of the preferable geometry in the rod bundle, where the bubbles are observed to exist, instead of in the space between any two rods, this void fraction of 0.25 applies to the local preferable area only, a.L. The local voids, aL, can be related to the average void by (Venkateswararao et al., 1982)... 

Martin, C. S., 1973, Transition from Bubbly to Slug Flow of Vertically Downward Air-Water Flow, Proc. ASME Symp., Atlanta, GA. (3)... 

Hovmand and Davidson (1971) review Stewart s criterion for the transition from bubbling to slug flow,... 

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