Showing papers in "International Journal of Multiphase Flow in 2006"

TL;DR: An optical measurement method for two-phase flow pattern characterization in microtubes has been utilized to determine the frequency of bubbles generated in a microevaporator, the coalescence rates of these bubbles and their length distribution as well as their mean velocity.

TL;DR: In this article, the authors report flow visualization measurements of the two-phase gas-liquid flow pattern and the liquid velocity distribution inside liquid plugs of an intermittent flow and present flow regime maps using different channel geometries and fluids.

TL;DR: In this paper, high-speed visualizations were performed simultaneously with heat transfer and pressure drop measurements to investigate the physics of flow boiling in parallel microchannel arrays, and local heat transfer measurements, obtained at three flow rates ranging from 35 to 60ml/min, show that at lower heat fluxes, the heat transfer coefficient increases with increasing heat flux.

TL;DR: In this article, a 15m long, 8.28 cm diameter, inclinable steel pipe using mineral oil (density of 830kg/m 3 and viscosity of 7.5mPa/s) and brine was used for two-phase flow experiments.

TL;DR: In this paper, a review of two-phase flow and flow boiling of mixtures in small and mini channels is presented, and the future research directions including both fundamental and applied research in this area have been indicated.

TL;DR: In this article, the dynamics of gas-liquid flows in a rectangular bubble column using Eulerian-Lagrangian simulations were studied and the simulated results were validated using wall pressure and voidage fluctuation measurements.

TL;DR: In this paper, the authors evaluated instability and heat transfer phenomenon under condition of periodic flow boiling of water and ethanol in parallel triangular micro-channels, and the dimensionless experimental values of the heat transfer coefficient were presented as the Nusselt number dependence on the Eotvos number and the boiling number.

TL;DR: In this article, numerical simulations of some capillary-driven flows are dealt with and the focus is on the wetting phenomenon in sintering-like flows and in the imbibition of liquids into a porous medium.

TL;DR: In this article, the authors identify the main events in the history of thought about irrotational flow of viscous fluids and identify the reasons why it is not necessary and typically not useful to put the viscosity to zero.

TL;DR: In this paper, the effect of upward and downward pipe inclinations on flow patterns, hold up and pressure gradient during two-liquid phase flows was investigated experimentally for mixture velocities between 0.7 and 2.5m/s and phase fractions between 10% and 90%.

TL;DR: In this article, a series of two-phase air-water experiments was carried out in order to study the initiation and the subsequent evolution of hydrodynamic slugs in a horizontal pipeline.

TL;DR: In this paper, direct numerical simulations are used to examine laminar bubbly flows in vertical channels and the results show that at steady state the number density of bubbles in the center of the channel is always such that the fluid mixture there is in hydrostatic equilibrium.

TL;DR: In this paper, a general heat transfer correlation for non-boiling gas-liquid flow with different flow patterns in horizontal pipes is proposed, and a flow pattern factor (effective wetted-perimeter) is developed and introduced into the proposed correlation.

TL;DR: In this paper, the theory-based closure relations for the wall and interfacial shear stresses obtained previously for laminar stratified flow, are extended to be applicable also to turbulent flows in either or both of the phases.

TL;DR: In this paper, a large eddy simulation coupled with a Lagrangian stochastic model has been applied to the study of droplet dispersion in a turbulent boundary layer, where the velocity of the fluid particle along the droplet trajectory is considered to have a large scale part and a small scale part given by a modified three-dimensional Langevin model using the filtered subgrid scale statistics.

TL;DR: In this article, the influence of using wall-corrected drag coefficients and of the lift force on the dispersed phase characteristics of a turbulent dilute gas-solid channel flow has been investigated.

TL;DR: In this article, an experimental investigation of gas-liquid counter-current flow in a vertical rectangular channel with 10 mm gap, at rather short distances from liquid entry, is reported.

TL;DR: Several continuous random walk (CRW) models were constructed to predict turbulent particle diffusion based on Eulerian statistics that can be obtained with Reynolds-Averaged Navier Stokes (RANS) solutions as mentioned in this paper.

TL;DR: In this article, the evolution of slugs from a highly disturbed stratified flow at the inlet was studied by measuring the holdup at a number of locations along a 20m length of 0.0763m pipe.

TL;DR: In this paper, the authors compared the bubble growth in water to that of a surfactant solution with negligible environmental impact, and found that the bubble shape is close to axially symmetric and vertically non-symmetric.

TL;DR: In this paper, the effects of surface inclination h and bubble volume V on the terminal Froude number were studied in details, and it was found that the increase of uT with V is not monotonous and four distinct sub-regimes, each characterized by a specific bubble shape, exist.

TL;DR: In this paper, the hydrodynamic characteristics of gas-liquid slug flow in an upward tube are investigated with limiting diffusion current probes, conductivity probes and digital high-speed video system.

TL;DR: In this paper, the authors used dimensionless scales of radius and time, proposed by the authors in a previous study, were used to quantitatively analyze the bubble departure radius and times during nucleate pool boiling, and the results obtained from dimensional analysis were compared with experimental data reported in many studies.

TL;DR: In this article, the authors describe the microscopic and macroscopic breakup characteristics of mono-dispersed droplets in relation to the breakup regimes, as well as the velocity and size distributions.

TL;DR: In this paper, an experimental three-dimensional reconstruction and visualization of stationary and transient flashing flow in a vertical pipe (47 mm diameter) is presented by means of wire-mesh sensors.

TL;DR: In this paper, a simple spray jet is designed to produce a two-phase slender shear flow in a co-flowing air stream with well-defined boundary conditions, which is made intentionally simple and easy to model so that the focus can be placed on the important aspects of droplet dispersion and evaporation.

TL;DR: In this paper, the effects of tube outlet direction, tube protrusion depth as well as mass flux, and quality on the air and water flow distribution were investigated for a round header.

TL;DR: In this article, a full velocity-scalar filtered mass density function (FMDF) formulation for large eddy simulation (LES) of a separated two-phase flow was developed.

TL;DR: In this article, the authors studied flow patterns, pressure drag reduction and heat transfer in a vertical upward air-water flow with the surfactant having negligible environmental impact in a tube of 2.5 cm in diameter.

TL;DR: In this paper, the role of secondary flows in the transport and dispersion of particles suspended in a turbulent square duct flow was investigated, and it was found that lateral mixing is enhanced for passive tracers and low-inertia particles due to the lateral advective transport that is absent in straight pipe and channels flows.