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Gas-liquid flow, in stirred

Several alternatives may be used to derive suitable pressure or pressure correction equations. In this section, we will discuss a specific option based on the work of Spalding (1980) and Carver (1984). This option has been used to simulate gas-liquid flows in stirred vessels (Ranade and van den Akker, 1994) and bubble columns (Ranade, 1992 1997) and was found to be quite robust. The method is illustrated here for two-fluid models. It can be extended to more than two phases following the same general principles. The overall method is an extended version of the SIMPLER... [Pg.210]

Lane, G.L., Schwarz, M.P. and Evans, G.M. (1999), CFD simulation of gas-liquid flow in stirred tank, 3rd Int. Symp. on Mixing in Industrial Processes, Japan. [Pg.324]

Ranade, V.V. and Deshpande, V.R. (1999), Gas-liquid flow in stirred reactors Trailing vortices and gas accumulation behind impeller blades, Chem. Eng. ScL, 54, 2305-2315. [Pg.324]

Ranade, V. V. (2000), Modeling of gas-liquid flows in stirred and bubble column reactors, CPCFD Meeting, Cincinnati, May 2000. [Pg.363]

Modeling and Simulation of Gas-Liquid Flow in Stirred Tank Reactors. 24... [Pg.19]

Lane GL, Schwarz MP, Evans GM. (2004) Numerical modeling of gas-liquid flow in stirred tanks. Chem. Eng. Sci., 60 2203-2214. [Pg.211]

Liquid residence-time distributions in mechanically stirred gas-liquid-solid operations have apparently not been studied as such. It seems a safe assumption that these systems under normal operating conditions may be considered as perfectly mixed vessels. Van de Vusse (V3) have discussed some aspects of liquid flow in stirred slurry reactors. [Pg.123]

Many of the situations encountered by reactor engineers involve (refer to Table 10.1) contact with more than one phase in a stirred tank. It is, therefore, essential to examine whether CFD models can simulate complex multiphase flows in stirred tanks. Here the case of gas-liquid flows in a stirred tank is considered. Similar methodology can be applied to simulate other two-phase or multiphase flows in stirred vessels. The computational snapshot approach discussed previously has been extended to simulate gas-liquid flows (see Ranade et al., 2001c for more details). A two-fluid model was used to simulate gas-liquid flow in a stirred vessel the model equations and boundary conditions are listed below. [Pg.311]

Ranade and Van den Akker [74], for example, used the snapshot method for simulating gas-liquid flows in baffled stirred tanks using a time after volume averaged two-fluid model for incompressible flows (as described in sect 3.3). These multiphase simulations also predicted the near-impeller flows with fair accuracy. Most important, the cavities due to the accumulation of gas in the low-pressure region behind the impeller blades were detected. [Pg.732]

Ranade VV, Van den Akker HEA (1994) A Computational Snapshot of Gas-Liquid Flow in Baffled Stirred Reactors. Chem Eng Sci 49(24B) 5175-5192... [Pg.754]

Manikowski, M., S. Bodemeia-, A. Ltibbert, W. Bujalski, and A. W. Nienow (1994). Measurement of gas and liquid flows in stirred tank reactors with multiple agitators. Can. J. Chem. Eng., 72, 769-781. [Pg.541]

The gas-liquid flow characteristics of stirred vessels depend both on the level of agitation and the rate of gas flow and can vary from the case of bubble column type operation to that of a full circulating tank, as shown in Fig. 5.123. The mixing characteristics and gas distribution obtained, obviously exert a considerable influence on the rate of mass transfer obtained (Harnby et al., 1985). [Pg.457]

When two phases are mixed together (gas-liquid, immiscible liquid-liquid), a fine dispersion of bubbles or drops and a high specific interfacial area are produced because of the intensive turbulence and shear. For this reason, resistance to interphase mass transfer is considerably smaller than in conventional equipment. In addition, a wide range of gas-liquid flow ratios can be handled, whereas in stirred tanks the gas-flow rate is often limited by the onset of flooding. Mass transfer coefficients (kLa) can be 10-100 times higher than in a stirred tank. [Pg.241]

Two-fluid or multifluid models can be extended to simulate not only gas-liquid flows but also any combinations of different phases present in stirred reactors. To simulate gas-liquid-solid, slurry reactors, liquid and solid phases are often lumped together and treated as a slurry phase with effective properties. This approximation is reasonable as long as the solid volume fraction is low ( 1 %). For higher solid loading. [Pg.316]

The value of kga can in certain circumstances be determined by purely physical experiments in the reactor, for instance in the case of piston-like countercurrent gas-liquid flow or when both phases are wel1-stirred. However, the rate of absorption depends on the residence time distribution in both phases that may be undetermined and in addition there is normally an appreciable resistance on the liquid side that must be taken into account. Thus the liquid side resistance can be eliminated and the rate of absorption can be made independent of the liquid side residence time distribution by using a solution which reacts instantaneously and irreversibly with the dissolved gas so that there is no back-pressure. Therefore,... [Pg.112]

Khopkar AR, Rammohan AR, Ranade W, Dudukovic MP Gas-liquid flow generated by a Rushton turbine in stirred vessel CARPT/CT measurements and CFD simulations, Chem Eng Sd 60 2215-2229, 2005. http //dx.doi.Org/10.1016/j.ces.2004.ll.044. [Pg.37]

Flow Reactors Fast reactions and those in the gas phase are generally done in tubular flow reaclors, just as they are often done on the commercial scale. Some heterogeneous reactors are shown in Fig. 23-29 the item in Fig. 23-29g is suited to liquid/liquid as well as gas/liquid. Stirred tanks, bubble and packed towers, and other commercial types are also used. The operadon of such units can sometimes be predicted from independent data of chemical and mass transfer rates, correlations of interfacial areas, droplet sizes, and other data. [Pg.708]

FIG. 23-25 Typ es of industrial gas/Hqiiid reactors, (a) Tray tower, (h) Packed, counter current, (c) Packed, parallel current, (d) Falling liquid film, (e) Spray tower, if) Bubble tower, (g) Venturi mixer, h) Static in line mixer, ( ) Tubular flow, (j) Stirred tank, (A,) Centrifugal pump, (/) Two-phase flow in horizontal tubes. [Pg.2105]


See other pages where Gas-liquid flow, in stirred is mentioned: [Pg.319]    [Pg.319]    [Pg.112]    [Pg.316]    [Pg.431]    [Pg.32]    [Pg.126]    [Pg.319]    [Pg.319]    [Pg.112]    [Pg.316]    [Pg.431]    [Pg.32]    [Pg.126]    [Pg.226]    [Pg.319]    [Pg.325]    [Pg.347]    [Pg.861]    [Pg.608]    [Pg.29]    [Pg.30]    [Pg.608]    [Pg.45]    [Pg.44]    [Pg.111]    [Pg.277]    [Pg.77]    [Pg.114]    [Pg.408]    [Pg.139]    [Pg.777]    [Pg.890]    [Pg.699]   


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