Showing papers in "International Journal of Multiphase Flow in 1998"

TL;DR: In this paper, a variety of liquid droplet evaporation models, including both classical equilibrium and non-equilibrium Langmuir-Knudsen formulations, are evaluated through comparisons with experiments with particular emphasis on computationally efficient procedures for gas-liquid flow simulations.

TL;DR: In this article, a numerical method to simulate liquid-vapor phase change is presented, based on the so-called single field formulation where one set of equations for conservation of mass, momentum and energy are written for the entire flow field.

TL;DR: In this paper, the authors measured the structure, size and velocity of the parent drop, and the sizes and velocities of drops produced by secondary breakup in the bag-burst regime.

TL;DR: In this paper, a two-dimensional, incompressible, multiphase particle-in-cell (MP-PIC) method is used to predict sedimentation of particles in an inclined vessel.

TL;DR: In this article, a dynamic simulation of pressure-driven flow of a non-neutrally buoyant suspension of spheres in a monolayer was performed by Stokesian Dynamics.

TL;DR: In this paper, an experimental study has been carried out to identify the different regimes of natural convective boiling of R-113 in a narrow rectangular vertical channel (confined space).

TL;DR: In this article, a Lagrangian approach is used to describe turbulent two-phase particulate flows, and a new model for particle dispersion in homogeneous turbulence is proposed, built on physical arguments quite different from those underlying the previous model.

TL;DR: In this paper, the effects of liquid viscosity on the mean liquid film thicknesses, wave heights, and gas-liquid interfacial shear stresses in the vertical-upward co-current annular flow in a 26.0mm inner diameter tube were investigated.

TL;DR: In this article, the authors propose to use simpler forms of the transport equations to represent transient phenomena in a two-phase gas-liquid flow in pipes, and solve these types of models using less time-consuming numerical algorithms.

TL;DR: In this paper, a phenomenological theory of sedimentation for flocculated suspensions was developed, which takes the compressibility of the flocs under their own weight and the permeability of the sediment into consideration.

TL;DR: In this paper, a two-fluid model is used to solve the momentum equations for a variable interface curvature, and the analysis identifies all the input dimensionless parameters which determine the solution for the stratified flow pattern.

TL;DR: In this article, the motion of large bubbles in tubes is investigated numerically with a two-dimensional, transient, finite difference model using a volume fraction specification to track the movement of the gas-liquid interface.

TL;DR: In this article, an experimental investigation on flow around an oscillating bubble and a solid ellipsoid with a flat bottom was conducted, where a single air bubble (equivalent diameter D e = 9.12mm) was attached to a small disk (∼1mm) at the end of a needle and suspended across a vertical square channel (100mm) by wire wherein water flowed downward at a constant flowrate.

TL;DR: In this article, the effect of a dilute suspension, of near neutral-density particles, on the wall turbulence in a horizontal channel was investigated by means of a laser Doppler anemomentry and flow visualization.

TL;DR: In this article, the conical probe geometry was optimized based on optical simulations and controlled piercing experiments to improve the performance of conical probes for gas-liquid flow dynamics. But their actual response is sensitive to small geometrical defects occurring at their tips.

TL;DR: In this article, the authors investigate the structure of upward air-water flow and its variation as the bubble-to-slug transition is approached, with a view to understanding the mechanism of the transition.

TL;DR: In this article, a two-phase, three-field annular flow model is used to calculate dryout power and post-dryout heat transfer in tube geometry and validation results are presented.

TL;DR: The use of helically coiled wires was found to increase the condensing heat transfer coefficients by as much as 100% above the plain tube values on a nominal area basis.

TL;DR: In this article, flow patterns, void fraction and friction pressure drop measurements were made for an adiabatic, vertical up-and-down, two-phase flow of air-water mixtures across a horizontal in-line, 5×20 tube bundle with a pitch-to-diameter ratio of 1.28.

TL;DR: In this article, the fluid displacement associated with the injection and subsequent translation of high Reynolds number bubbles in a thin gap is examined experimentally, and compared with a theoretical model based on a two-dimensional inviscid flow calculation.

TL;DR: In this paper, a model is developed in which the dimensions of the shear layer, the region near the free surface, is assumed thin thereby permitting the governing equations to reduce to Prandtl's boundary layer equations which are solved to obtain the depth and velocity profiles within the layer.

TL;DR: In this article, the particle diffusion coefficient is expressed in terms of the fluid diffusivity, taking into account the inertial effect and the crossing trajectories effect, and the analytical solution for the particle concentration in a one-dimensional problem between two horizontal plates is found, and is used to calculate the relative deposition between the top and the bottom wall.

TL;DR: In this paper, two new shapes, namely, cone+cylinder (2C) and cone +cylinder+cone (3C), are considered. And they are both effective for simultaneous gas detection and gas velocity measurements, but the latter, free of proximity detection, appears to be the most promising due to a calibration curve, i.e., the relationship between signal rise time and interface velocity.

TL;DR: In this article, the axial pressure distributions along the element including that along upstream and downstream tangent lines consisting of long sections of straight pipe of the same diameter were measured to use as baselines.

TL;DR: In this article, an experimental investigation of a turbulent air-water bubbly flow in a plane vertical mixing layer is presented, where the mean velocity fields in both phases present self-similar evolutions that preserve the main characteristics of single-phase mixing layer.

TL;DR: In this article, a straight circular pipe was injected vertically downward through a straight curved pipe onto a water bath contained in a cylindrical vessel and three types of bubble dispersion patterns were observed with respect to the distance from the pipe exit to the undisturbed bath surface when the distance was short, small bubbles were generated at the bath surface and they dispersed in the whole bath.

TL;DR: In this article, the motion of two spherical particles settling in close proximity under gravity in Newtonian fluids was investigated experimentally for particle Reynolds numbers ranging from 0.01 to 2000, and it was observed that particles repel each other for Re>0.1 and that the separation distance of settling particles is Reynolds number dependent.

TL;DR: In this paper, the theoretical analysis to obtain the flow characteristics of multiphase mixtures in a vertically fixed air-lifting pipe is concerned with the analysis of the flow pattern transitions of gas phase from bubbly to slug flows and from slug to churn flows.

TL;DR: In this paper, the phase distribution and junction pressure drops of air-water mixtures (1.5 bar) in two reduced tee junctions were investigated and compared with existing models of pressure drop and phase distribution.

TL;DR: In this article, the effects of electric fields on the behavior of a bubble attached to a wall, basic experiments on the deformation and departure of bubble are carried out under d.c/a.c. applied voltages, where three types of electrodes are used, to examine the bubble behavior by the nonuniformity of the electric field.