This work presents a computational study of flow behaviour in a bubbling fluidized bed. The model is developed by using the commercial CFD code Fluent 6.3. The model is based on an Eulerian description of the gas and the particle phase. Different drag models are used and compared. The computational results are validated against experimental results. The experimental data are taken from Hulme (2...

The effect of tube diameter on two-phase flow patterns was investigated in circular tubes with inner diameters of 0.6, 1.2, 1.7, 2.6, and 3.4mm using air and water. The gas and liquid superficial velocity ranges were 0.01–50 and 0.01–3m/s, respectively. The gas and liquid flow rates were measured and the two-phase flow pattern images were recorded using high-speed CMOS camera. The flow patterns...

Flow fields and bubble size distribution are two critical issues in the determination of mass transfer and reaction rate in bubble columns. In this work the hydrodynamics of bubble driven flow was investigated in a laboratory scale cylindrical bubble column. The column was a semi batch reactor which was initially filled with tap water and only gas was evenly fed to the column from the bottom wi...

Results of experimental studies of gas hold-up in a liquid stirred mechanically in a reactor, which was equipped with double stirrers on a common shaft, are presented. Coalescing and noncoalescing gas—liquid systems were tested. The measurements were carried out for aqueous solutions of glucose and glucose sirup, as well as for different configurations of dual high-speed impellers. Stirred tank...

this study is concerned with the prediction of particles’ velocity in a dilute turbulent gas-solidboundary layer flow using a fully eulerian two-fluid model. the closures required for equationsdescribing the particulate phase are derived from the kinetic theory of granular flows. gas phaseturbulence is modeled by one-equation model and solid phase turbulence by mlh theory. resultsof one-way and...

Rigorous analysis of the determinants of volumetric mass transfer coefficient (kLa) and its accurate forecasting are of vital importance for effectively designing and operating stirred reactors. Majority of the available literature is limited to systems with low solids concentration, while there has always been a need to investigate the gas-liquid hydrodynamics in tanks handling ...

Studies attempting to optimise photosynthetic biogas upgrading by simultaneous investigation of the bubble column-photobioreactor setup have experienced considerable variability in results and conclusions. To identify sources such variation, this work quantitatively compared seven design factors (superficial gas velocity; liquid flow rate (L/G) ratio; empty bed residence time; inlet pH; alkalin...

The investigations of bubble formation dynamics at a cross-junction in straight milli-channel were reported. process could be divided into the filling and squeezing stages, their frequencies compared various conditions. It was found that controlled mainly by gas liquid superficial velocities, respectively. related to gas-liquid velocity ratios, length. then analyzed considering length finger ri...

the local solid flow structure of gas-solid bubbling fluidized bed was investigated to identify and characterize the particle clusters. extensive mathematical calculations were carried out using the energy-minimization multi-scale (emms) approach for evaluating cluster properties including the velocity, the size and the void fraction of clusters in the dense phase of the bed. the results showed...

The present work aims to study the phenomena of droplet entrainment from water pool in a confined atmosphere, which could be either consequence boiling or depressurization. Eventually, these droplets are entrained by streaming gas (superficial velocity) settling down due gravity. number correlations developed so far quantify based on empirical, semi-empirical and theoretical approaches, but the...