The objective of this paper is to develop a reliable, yet-simple, correlation for the liquid phase axial dispersion coefficient Dax,L in bubble column reactors. In order to develop this correlation we carried out measurements of the centre-line liquid velocity VL(0) and Dax,L in bubble columns of diameter DT=0.174, 0.38 and 0.63 m with the air-water system. The measurements were performed in th...

Refinements in laser technology (few-cycle pulse generation, chirped pulse amplification) combined with supercomputer-based plasma simulations have brought the discipline of relativistic laser-matter interaction to a new level of predictability. This was recently demonstrated by the generation of brilliant electron bunches with energies on the 0.1-1-GeV-scale. Our plan is to utilize such lasera...

People have long been fascinated by bubbles and foams dynamics, and since the pioneer work of Leonardo da Vinci in the early 16th century, this subject has generated a huge bibliography. However, only very recently, much interest was devoted to bubbles in champagne wines [1]. Small bubbles rising through the liquid, as well as a bubble ring (the so-called collar) at the periphery of a flute pou...

A Lagrangian-Eulerian numerical scheme for the investigation of bubble motion in turbulent flow is developed. The flow is analyzed in the Eulerian reference frame while the bubble motion is simulated in the Lagrangian one. Finite volume scheme is used, and SIMPLEC algorithm is utilized for the pressure and velocity linkage. The Reynolds stresses are modeled by the RSTM model of Launder. Upwind ...

bubble columns are gas- liquid contactors that are widely used in chemical and bio- chemical industries. high mixing that result in high heat and mass transfer rates are amongst their advantages. heat transfer in a bubble column having a bundle of heaters investigated and the variation of heat transfer coefficient with variation in heaters pitch to diameter ratios in a bundle of heaters reporte...

Detecting bubble in two-phase flow has been a basic issue in two-phase flow systems. A new method for measuring the frequency of bubble formation is presented in this paper. For this purpose, an electronic device was designed and constructed which works based on a change in intensity of laser beam. For this purpose, continues light beam is embedded just above the needle, which is received by a ...

Shell and Tube heat exchangers are the heat exchangers that are most widely used in industries and for other commercial purposes. There are many techniques that have been utilized to enhance the heat transfer performance of the shell and tube heat exchangers. Air bubble injection is one of the promising and inexpensive techniques that can create turbulence in the fluids resulting in to enhancem...

A modified model has been analytically developed to describe the induction time of an elliptic air bubble in contact with an elliptic hydrophobic oil droplet. The role of hydrophobicity was revealed in the slippage of liquid over the surfaces of bubble and droplet. In this condition, the analytical relationships for pressure distribution and consequently hydrodynamic resistance force through th...