Liquid ring flow

Serizawa et al. (2002) studied the flow patterns in steam-water flow. Figure 2.29 shows their observations in a 0.05 mm glass channel. Here a new pattern was identified, namely, liquid ring flow. 

Further increase in the gas flow rate in liquid ring flow leads to a liquid lump flow, of which the high-speed core gas entrains the liquid phase and liquid lumps slide... 

Figure 5.9 shows various interesting aspects of two-phase flow patterns obtained in this observation. It should be noticed from these pictures that a variety of two-phase flow patterns were encountered in a clean micro-channel. The authors noticed that in a very clean tube, many small individual bubbles flow in a discrete way in the tube without coalescence in bubbly flow. The most interesting thing is the special flow pattern given in Fig. 5.9d, where several bubbles with various shapes are connected in a series by the gas stems located at the tube center line. The liquid ring flow is also clearly seen in Fig. 5.9e. 

Feng, 2001 7l=0.003-17.52 m/s, 7g=0.0012- 295.3 m/s. Steam water, ranges not given diameters of 50 pm for air-water, and 25 pm for steam-water two-phase flow, steam- water details not given patterns identified over the ranges of flow rates studied patterns identified liquid ring flow and liquid lump flow. 

Because steel rings have thinner walls, it seems that the liquid should flow and wet this material a litde better than ceramic. 

Vacuum capacities and operating ranges, table, 344, 355 Ejectors, 344, 357 Integrated systems, 344 Liquid ring pumps, 344 Rotary lobe blowers, 344 Rotary piston pumps, 344 Rotary vane pumps, 344 Vacuum equipment, 343 Applications diagram, 352 ASME Code, 344 Pumps, 382 Steam jets, 357 Vacuum flow,... 

In order to see the magnitude of the variables, consider the aeration of a cylindrical tank lm deep and 1 m diameter. Nitrogen is sparged to desorb oxygen from the liquid. Water flows continuously across the tank at a rate of 1 L/s. The nitrogen flow-rate is 0.061 kg/s, and the temperature is 20°C. The results of the outlined calculation of a suitable sparger ring, are as follows ... 

Figure 4.39 Flow patterns for the nitrogen-water (a) Slug flow Ug — 0.5 m/s, U = 0.1 m/s (b) system observed for the smooth mixer in the annular flow Ug — 5.5 m/s, U = 0.07 m/s (c) microchannel used attheTU/e. The images were ring flow Ug = 20m/s, U = 0.2m/s (d) churn recorded atthe indicated superficial gas (Ug) and flow Ug = 50m/s, U — 0.5 m/s (by courtesy of superficial liquid velocities (U ). The channel has Wiley-VCH Verlag GmbH) [279]. a rectangular cross section of 100 pm X 50 pm.

Wad flow (66,67,140,141-149). The tendency of liquid to flow toward the walls of packed columns is a fundamental phenomenon associated with packed-column hydraulics. The development of wall flow is illustrated in Fig. 9.4 using typical measurements by Hoek (140) in a pilot-scale column. The column diameter was 20 in, and the outer distributor nozzle was located about 1.5 in from the wall. In these experiments, wall flow was defined as the flow in the outer ring of the column (with an area of 16 percent of the column cross section). 

The flow pattern may change with length. Satterfield and Ozel [7] observed that as bubbles and slugs flow down, a liquid ring frequently appears within a bubble. The ring grows in thickness and finally fills the complete cross section of a capillary, thus splitting the bubble in two. 

Many chemical treatises give instructions on the use of different kinds of furnaces. Besides the calcinatory furnaces for reducing metals and minerals to a fine powder, there was the athanor. This contained a deep pan of sifted ashes. The material to be heated was placed in a firmly sealed container and covered with the ashes. This method is rather like a modem chemist s sand bath. Then there was the descensory furnace, which had a funnel with a lid. Liquid could flow down the stem of the funnel into a receptacle. Another sort of furnace was known as the dissolving furnace. It consisted of a small furnace supporting a pan full of water. In the pan were rings to hold glass containers. It... 

Cause As was suspected, the reflux distributor was tilted allowing all the liquid to flow down one side of the column. The distributor had not been securely attached to its support ring because the installation drawings didn t specify a method of attachment. A clever troubleshooter confirmed the hypothesis prior to shutdown by measuring vessel wall temperatures with a contact pyrometer stuck through the insulation. One side of the column was, of course, colder than the other for several feet below the reflux distiibutor. 

Researchers have worked to alleviate the problems of separation and corrosion in processes such as the oxo process by designing catalysts that are confined in a separate phase from the reactants (see Section 14.2.4). A commercially successful approach for propene hydroformylation resulted from preparation of water-soluble rhodium complex catalysts by sulfonation of the phenyl rings of the triphenyl phosphine ligands. The catalyst is used in a reactor with two liquid phases the propene is concentrated in the organic phase and the catalyst in the aqueous phase near the interface. The CO -I- H2 is bubbled into a mixed reactor, and the two-phase liquid product flows to a settler the organic product flows to downstream separation devices, and the aqueous phase with the catalyst is recycled to the reactor. 

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