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Smart RTD for multiphase flow systems

Simcik, M.; Ruzicka, M. C.; Mota, A.; Teixeira, J. A.

A relatively new concept is presented for evaluation of the fluid age distribution a = a(x,t) within the interior of an apparatus. In the standard RTD approach, the tracer study is performed and the residence time distribution is obtained. In the new approach denoted as SRTD, the fluid age is considered as the field quantity and the governing equation is formulated for its spatio-temporal distribution within th...


CFD simulation and experimental measurement of gas holdup and liquid interstiti...

Simcik, M.; Mota, André; Ruzicka, M. C.; Vicente, A. A.; Teixeira, J. A.

This paper documents experiments and CFD simulations of the hydrodynamics of our two-phase (water, air) laboratory internal loop airlift reactor (40 l). The experiments and simulations were aimed at obtaining global flow characteristics (gas holdup and liquid interstitial velocity in the riser and in the downcomer) in our particular airlift configurations. The experiments and simulations were done for three dif...


Meniscus dynamics in bubble formation : a parametric study

Stanovsky, Petr; Ruzicka, M. C.; Martins, A.; Teixeira, J. A.

This study brings new experimental data on the bubble formation process with a particular focus on the behaviour of the gas–liquid interface (meniscus) inside a transparent orifice on a perforated plate. The meniscus plays an important role by coupling the gas and liquid sides. The goal was to find the effect of five important control parameters on the bubble production and the meniscus behaviour (orifice diame...


Euler-euler simulation of gas-liquid and gas-liquid-solid airlift reactors : ca...

Simcik, M.; Havlica, J.; Ruzicka, M. C.; Drahoš, J.; Teixeira, J. A.; Brányik, Tomáš


Gas holdup in laboratory scale bubble column : CFD simulations vs. measurements

Simcik, M.; Kulaviak, L.; Havlica, J.; Ruzicka, M. C.; Drahoš, J.; Teixeira, J. A.


Effect of solids on homogeneous–heterogeneous flowregime transition in bubble c...

Mena, P. C.; Ruzicka, M. C.; Rocha, F. A.; Teixeira, J. A.; Drahoš, J.

Experiments were conducted to study the effect of the presence of the solid phase on the homogeneous–heterogeneous flow regime transition in a bubble column 0.14m diameter. Air, distilled water and calcium alginate beads (2.1 mm, 1023 kg/m3) at concentrations c=0–30% (vol.) were the phases. The basic data were the voidage–gas flow rate dependences. The critical point, where the homogeneous regime loses stabilit...


Effect of solids on flow regime transition in three-phase bubble columns

Mena, P. C.; Rocha, F. A.; Teixeira, J. A.; Drahoš, J.; Ruzicka, M. C.

In bubble column reactors there are two principal flow regimes [1,2,3], the homogeneous (HoR) and the heterogeneous (HeR). These reactors have different behaviour in HoR and HeR, thus the dependences of the rates of mass, heat and momentum transfer on the design and operating parameters (such as reactor geometry, gas and liquid flow rates and properties of the contacting phases) are also very different. Therefo...


Effect of solid particles on flow regimes in bubble columns

Mena, P. C.; Plzáková, M.; Ruzicka, M. C.; Drahoš, J.; Večeř, M.; Wichterle, K.; Teixeira, J. A.


Effect of viscosity on homogeneous–heterogeneous flow regime transition in bubb...

Ruzicka, M. C.; Drahoš, J.; Mena, P. C.; Teixeira, J. A.

Experiments were performed in a cylindrical 0.14m diameter bubble column with a metal perforated plate. Air and aqueous solutions of glycerol with viscosity 1–22mPa s were the phases. Gas holdup was measured and plotted against the gas flow rate. The critical point where the homogeneous–heterogeneous regime transition begins was determined by the drift-flux plot of the primary data. The homogeneous regime stabi...


Effect of surfactants on homogeneous regime stability in bubble columns

Mena, P. C.; Ruzicka, M. C.; Drahoš, J.; Teixeira, J. A.; Rocha, F. A.


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    Financiadores do RCAAP

Fundação para a Ciência e a Tecnologia Universidade do Minho   Governo Português Ministério da Educação e Ciência Programa Operacional da Sociedade do Conhecimento União Europeia