Aerated stirred vessel

In some way, introducing an increased particle drag by means of Eq. (17) resembles the earlier proposal raised by Bakker and Van den Akker (1994b) to increase viscosity in the particle Reynolds number due to turbulence (in agreement with the very old conclusion due to Boussinesq, see Frisch, 1995) with the view of increasing the particle drag coefficient and eventually the bubble holdup in the vessel. Lane et al. (2000) compared the two approaches for an aerated stirred vessel and found neither proposal to yield a correct spatial gas distribution. 

In the 1980s, Issa and Gosman (1981), Pericleous and Patel (1987), and Tragardh (1988) made the first attempts to simulate aerated stirred vessels computationally. Their results were rather approximate indeed, and were not validated by means of experimental data. 

Challenge 2.4. Relationship between mixedness and impeller rotational speed in an aerated stirred vessel... 

The aim of the operation of an aerated stirred vessel is classified into two groups ... 

Challenge 5.3. Bubble size distribution in aerated stirred vessel 1. Scope... 

The aerated stirred vessel has been widely operated in chemical industries. The aim of gas-liquid mixing is to make the bubbles small in order to accelerate the mass transfer between the gas and the liquid. In the case of gas-liquid mixing, the gas that flows out from a sparger is trapped once by the impeller and then discharged as bubbles. The mixing state of the gas-liquid mixing is classified into three states ... 

To examine whether the new PSD defined by Eq. (5.18) can sufficiently express bubble size distribution in an aerated stirred vessel. 

The aerated stirred vessel is placed in a square vessel that is filled with water to obtain the picture of the bubbles. The impeller is rotated at a fixed rotational speed and the nitrogen gas is fed at a fixed flow rate. After confirming that the flow in the vessel has attained steady state, the images of bubbles are obtained by a video camera. By using these images, the bubble size distribution is estimated by fitting new PSD defined by Eq. (5.18). 

Figure 5.4 Data of bubble size probability density distribution in an aerated stirred vessel and fitted PSD curve based on new PSD function.

Venneker BCH, Derksen JJ, van den Akker HEA (2002) Population Balance Modeling of Aerated Stirred Vessels Based on CFD. AIChE J 48(4) 673-685 Weisbach JL (1845) Lehrbuch der Ingenieur-und Machinenmechanick, Braun-schwieg... 

Venneker, B. C. H., Derksen, J. J. Van den Akker, H. E. A. 2002 Population balance modelling of aerated stirred vessels based on CFD. AIChE Journal 48, 673-685. 

Aerated, stirred vessels can be called standard or reference bioreactors (Dechema, 1982) Equipped with various stirrers, they are generally suitable for most uses (Zlokarnik, 1972). Additional mixing of the fluid can be obtained by building in various baffles and fins. A new development is the so-called totally filled bioreactor (Karrer, 1978 Puhar et al., 1978). 

Kawase et al. [62] 230 CMC solutions 0.48-1 0.001-2.32 Mass transfer in bubble columns and aerated stirred vessels. 

Venneker BCH, Derksen JJ, Van den Akker HEA Population balance modeling of aerated stirred vessels based on CFD, AIChE J 48 673-685, 2002. http //dx.doi.org/10.1002/ aic.690480404. 

The topic of the drag coefficient in multiple particle systems has regained interest because of the CFD simulations of turbulent multiple particle systems such as agitated sohd suspensions, aerated stirred vessels, solid—liquid fluidized beds, and gas-sohds cyclones. A recent review on this topic can be found in Ghatage et al (2013) who also presented new experimental data on the shp velocity of a foreign particle in sohd—Uquid fluidized beds. 

---