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Flow in Stirred Vessels

Turbulent Flow in Stirred Vessels Turbulence parameters such as intensity and scale of turbulence, correlation coefficients, and... [Pg.1629]

Ranade, V.V., 1997. An efficient computational model for simulating flow in stirred vessels a case of Rushton turbine. Chemical Engineering Science, 52, 4473-4484. [Pg.319]

Flow in stirred vessels was also investigated by Holmes et al. (H5), who simulated mass transfer in a diaphragm diffusion cell stirred by magnetic stirrer bars. This is a good example of a simple model study with a direct practical purpose. A minimum stirring speed in such cells is necessary to avoid appreciable errors in the cell constant. The experiment permits this stirring speed to be related to the solution properties. [Pg.275]

In addition, it is dubious whether this new correlation due to Brucato et al. (1998) should be used in any Euler-Lagrangian approach and in LES which take at least part of the effect of the turbulence on the particle motion into account in a different way. So far, the LES due to Derksen (2003, 2006a) did not need a modified particle drag coefficient to attain agreement with experimental data. Anyhow, the need of modifying particle drag coefficient in some way illustrates the shortcomings of the current RANS-based two-fluid approach of two-phase flow in stirred vessels. [Pg.196]

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]

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]

Gosman, A.D., Lekakou, C., Politis, S., Issa, R.I. and Looney, M.K. (1992), Multi-dimensional modeling of turbulent two-phase flows in stirred vessels, AIChE J., 38, 1946-1956. [Pg.324]

Ranade, V.V, Tayaliya, Y. and Choudhury, D. (1997), Modeling of flow in stirred vessels comparison of snapshot, multiple reference frame and sliding mesh approaches. Presented at 16th NAME Meeting, Williamsberg, June 22-21. [Pg.324]

T irbulent Flow in Stirred Vessels Turbulence parameters such as intensity and scale of turbulence, correlation coefficients, and energy spectra nave been measured in stirred vessels. However, these characteristics are not used directly in the design of stirred vessels. [Pg.1947]

Gosman AD, Lekakou C, Polits S, Issa RI, Looney MK (1992) Multidimensional Modeling of Turbulent Two-Phase Flows in Stirred Vessels. AIChE J 38(12) 1946-1956... [Pg.493]

Basara et al [3] simulated single- and two-phase turbulent flows in stirred vessels equipped with six- and four blade Rushton-t3q)e turbines using the sliding mesh impeller method. To describe turbulence in the liquid phase a standard k-e model was used for single phase calculations and an extended k-e model was employed for the two-phase simulations. These simulations were performed in transient mode with 1 (ms) time steps. The whole calculation contains 3900 time steps, which means approximately 4s of real time and 17 complete rotations of the impeller. One such simulation took 13 days of CPU time using an Intel single processor with 2.6 GHz). The flow patter predictions were compared with experimental data and fair agreement was obtained. It was stated that the standard k-e model over-predicted the... [Pg.748]

Ranade, V.V. (1997). An Efficient Computational Model for Simulating Flow in Stirred Vessels a Case of Rushton Turbine, ChemESci. 53(24), pp. 4473 84. [Pg.199]

Molen, van der, k. andMAANEN, VAN, H. R. E. Chem. Eng. Sci. 33 (1978) 1161. Laser-Doppler measurements of the turbulent flow in stirred vessels to establish scaling rules. [Pg.311]

Turbulent Flow in Stirred Vessels Turbulence parameters... [Pg.1633]


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