The hydrodynamics of bubble columns in the heterogeneous regime is revisited. Focusing on air-water systems at large aspect ratio, we show from dimensional analysis that buoyancy equilibrates inertia, and velocities scale as $(gD\varepsilon)^{1/2}$, where $D$ column diameter, $\varepsilon$ void fraction $g$ gravitational acceleration. From new experiments a $0.4$m diameter with ${\cal{O}}(10^3)...

In this paper, a CFD model of syngas flow in slurry bubble column was developed. The model is based on an Eulerian-Eulerian approach and includes three phases: slurry of solid particles suspended in paraffin oil and syngas bubbles. Numerical calculations carried out for catalyst particles, bubble coalescence and breakup included bubble-fluid drag force and interfacial area effects. Also, the ef...

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...

A new technique dedicated to bubble velocity and size measurements in complex bubbly flows is proposed. This sensor combines the phase detection capability of a conical optical fiber with from Doppler signal induced by an interface approaching extremity. It provides translation bubbles projected along probe axis uncertainty at most 14%. has been successfully exploited 0.4 m diameter column. In ...

Microchannel heat sinks typically consist of parallel channels connected through a common header. During flow boiling random temporal and spatial formation of vapor bubbles may lead to reversed flow in certain channels which causing an early CHF condition. Inside the microchannels the liquid surface tension forces is expected to play an important role and impact the vapor bubble growth and corr...